Alex Spokoyny UCLA

Boron Cluster Building Blocks and Synthetic Reagents


Chemistry

February 17, 2020
Kent 120 | Monday, 3:45 pm

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Vladimir Narovlansky, Princeton University


Kadanoff Seminar

February 17, 2020
MCP 201 | Monday, 1:30 pm

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Too much semiannual amplitude in the daily temperature

Who ordered that?

Talk about the weather: 12:00
Really talk about the weather: 12:15
MRSEC Baglunch

February 14, 2020
GCIS E123 | Friday, 12:00 pm

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William Lanouette, Atomic Heritage Expert and Author


Physics Colloquium

February 13, 2020
KPTC 106 | Thursday, 3:30 pm

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Jianfeng Lu, Duke University

Coordinate-Descent Full Configuration Interaction

The leading eigenvalue problems arise in many applications. When the dimension of the matrix is super large, such as for applications in quantum many-body problems, conventional algorithms become impractical due to computational and memory complexity. In this talk, we will describe some recent works on new approaches for the leading eigenvalue problems based on randomized and coordinate-wise methods. In particular, we will introduce the coordinate-descent full configuration interaction for quantum chemistry problems.
(joint work with Yingzhou Li and Zhe Wang).
JFI Special Seminar

February 13, 2020
GCIS W301 | Thursday, 1:30 pm

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Marko Lončar, Harvard

New Opportunities with Old Optical Materials

Lithium niobate (LN) is an “old” material with many applications in optical and microwave technologies, owing to its strong electro-optic (EO) coefficient, second order nonlinearity, and piezoelectricity. Conventional - discrete - LN components, the workhorse of the optoelectronic industry for many decades, are reaching their limits, however. I will discuss our efforts aimed at the development of integrated LN photonic platform aimed at applications in optical communications (classical and quantum) and microwave photonics. Examples include high-performance (EO) modulators, EO and Kerr frequency combs, ad frequency converters. Diamond is another “old” material with remarkable properties! It is transparent from the ultra-violet to infrared, has a high refractive index, strong optical nonlinearity and a wide variety of light-emitting defects of interest for quantum communication, computation and sensing. I will discuss our recent efforts focused on the control of silicon vacancy color center using nanomechanical devices including free-standing nanobeams and surface acoustic waves.
Molecular Engineering

February 12, 2020
ERC 161 | Wednesday, 2:00 pm

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Jeremy England, GSK AI

Cancelled


Computations in Science

February 12, 2020
KPTC 206 | Wednesday, 12:15 pm

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Yun Liu, University of Illinois

New Functions in Organic Materials through Molecular Designs


Chemistry

February 11, 2020
Kent 120 | Tuesday, 1:45 pm

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Matthew Good, PhD, Cell & Devel Biol and Bioengineering, Upenn

Sequence Determinants & Fidelity of RGG Domain Condensation to Form Membraneless Organelles

Coacervation of intrinsically disordered proteins (IDPs) commonly underlies formation of membraneless organelles, which compartmentalize molecules intracellularly in the absence of a lipid membrane. However, to date, protein coacervation cannot be predicted from primary sequence. Using a combination of predictive coarse-grained modeling, in vitro characterization and in vivo expression we characterized the chemical determinants of IDP phase separation for the disordered RGG domain from the scaffold protein LAF-1. We identified regions that have high contact probability and deletion of which significantly disrupt protein condensation in vitro and in vivo. We designed sequence variants to investigate the role of charge patterning on phase behavior and found that shuffled sequences with greater charge segregation dramatically enhances propensity to phase separate. Mutation of tyrosine to phenylalanine, or arginine to lysine, dramatically perturbed RGG phase separation, and all-atom models highlight the special role of arginine in sp2-pi interactions. Building off of this platform we are identifying chemical principles that regulate the fidelity of selective protein coacervation and prevent inappropriate mixing of disordered proteins. Finally, we demonstrate the utility of RGG-based constructs for cellular engineering. By layering enzymatic and optical regulatory handles to regulate protein solubility and valency, we can control protein condensation to form synthetic membraneless organelles in cells. Together, these studies identify key biophysical principles of RGG domain condensation, including conserved motifs, critical residues and charge patterning, while also advancing a predictive framework to identify and design sequences that phase separate.
Biophysical Dynamics

February 11, 2020
GCIS W301 | Tuesday, 12:00 pm

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Eric Kool, Stanford University

Designer Nucleotides and Molecular Probes of DNA Repair


Chemistry

February 10, 2020
Kent 120 | Monday, 3:45 pm

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Sasha Migdal, New York University

Mathematics of operator growth in quantum many-body systems

The loop equations in turbulence are reviewed, both theory and comparison with numerical experiments and some physical experiments as well. We propose the model of 3D Turbulent statistics as String Theory on the phase boundaries of the 3D Ising model. Both mathematical justification from the Euler and Helmholtz equations and the resulting physical properties are discussed, time permitting.
Kadanoff Seminar

February 10, 2020
MCP 201 | Monday, 1:30 pm

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Capturing the texture of a fracture by quantitative measures

Mangiamo 12:00
Parliamo 12:15
MRSEC Baglunch

February 7, 2020
GCIS E123 | Friday, 12:00 pm

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Meg Urry, Yale University

2020 Equity, Diversity and Inclusion Colloquium


Physics Colloquium

February 6, 2020
GCIS W301 | Thursday, 3:30 pm

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Xufeng Zhang, Center for Nanoscale Materials, Argonne National Laboratory

Experimental Observation of an Exceptional Surface in Hybrid Magnonic Systems

Exceptional points (EPs) are singularities of eigen-energies in a non-Hermitian system that is open to the environment. Intriguing phenomena have been previously observed around EPs, including exceptional sensitivity, unidirectional signal propagation, etc. However, these demonstrations of EPs are limited to zero-dimensional points and one-dimensional lines. In this talk, I will show the first experimental realization of an exceptional surface (ES) – a continuous three-dimensional surface of EPs. This is achieved by constructing a four-dimensional synthetic space, taking advantage of the multiple independent tuning parameters of a cavity magnon polariton system. Magnon polaritons are hybrid excitations of electromagnetic waves and spin waves, which have recently emerged as a promising candidate for coherent information processing. The observed ES in the magnon polariton system can further coalesce into an exceptional saddle point in the four-dimensional parameter space, which exhibits novel complex anisotropic behaviors. This work provides a new pathway to engineer non-Hermitian systems, and opens up new application opportunities such as robust mode conversion and high-sensitivity sensing. Host: Peter Littlewood, 4-9879 or via email to littlewood@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI Special Seminar

February 5, 2020
GCIS W301 | Wednesday, 2:00 pm

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Justin Burton, Emory University

Intermittent Dynamics and "Turbulence" in a Many-Body System

Complex systems are known to exhibit emergent properties that are missing on the constituent level. An example is the appearance of intermittent transitions between distinct dynamical states. Using a levitated, quasi-2D layer of charged microparticles, our recent experiments (Gogia et al., PRL, 2017) showed that a nonequilibrium, many-body system can display intermittent dynamics by switching between an ordered, crystalline state and a gas-like, excited state. The emergent dynamics are a direct consequence of coupling between the inertial dynamics, structural disorder induced by particle size variation, and external noisy forcing. The behavior can be reproduced is a simulation with as little as 50 particles. The key lies in a separation of energy scales. Energy pumped into one degree of freedom will eventually couple non-linearly to other excitable modes and thermalize the system. The behavior bears a striking resemblance to the transition to turbulence in pipe flow, where increasing the flow velocity leads to intermittent "puffs" of turbulence. This transition also depends sensitively on disorder through the roughness of the pipe walls. In analogy to the Reynolds number, we are able to describe our system through a simplified set of equations and a single dimensionless number characterizing the ratio of external forcing to dissipation. This analogy may help identify the minimal ingredients for observing such intermittent, turbulent dynamics in other discrete systems.
Computations in Science

February 5, 2020
KPTC 206 | Wednesday, 12:15 pm

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Tobin Marks, Northwestern University

Soft Matter-Hard Matter Synergy for Flexible Electronics and Solar Cells


Chemistry

February 5, 2020
GCIS W301 | Wednesday, 12:00 pm

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Mufan Li, University of California Berkeley

Designing Electrocatalytic Sites at the Atomic Level


Chemistry

February 4, 2020
ERC 401 | Tuesday, 3:15 pm

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Rebecca Kramer-Bottiglio, Yale University

Programmable Composites for Stiffness-Changing and Shape-Shifting Soft Robots

Soft robots have the potential to adapt their morphology, properties, and behavioral control policies towards different tasks or changing environments. This adaptive capability is often inspired by biological systems. For instance, humans can transition between forceful and gentle tasks by controlling the stiffness of skeletal joints through co-contraction of antagonistic sets of muscles. In another example, the remarkably dexterous motion achieved by skeleton-free animal parts such as elephant trunks, octopus arms, and human tongues is attributed to selective contraction of layers of uni-directional muscle fibers. During this talk, I will present recent work towards programmable composites that address variable stiffness properties and variable trajectory motions inspired by these capabilities in animals. First, I will present a particulate additive designed to undergo a repeatable solid-liquid phase change within a polymeric matrix and demonstrate its use to achieve unprecedented changes in bulk material stiffness and elasticity. The solid-liquid phase change of low-melting-point metallic inclusions allows a composite to dramatically adjust its mechanical response, as demonstrated in two matrix materials: a thermoset epoxy and a silicone elastomer. Second, I will describe a soft composite lamina comprised of an elastic matrix with uni-directionally embedded inextensible fibers and an adhesive backing, which was inspired by soft body control strategies using fiber- architectures. In contrast to existing soft actuators with fixed deformation trajectories, this composite is simply placed on the surface of an inflatable body to govern its deformation trajectory, can be re-arranged in-situ to change this trajectory, and is created using a high throughput, automated manufacturing process.
Molecular Engineering

February 4, 2020
ERC 161 | Tuesday, 11:00 am

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Tobin Marks, Northwestern University

Surface Science Meets Homogeneous Catalysis. Surfaces as Unique Activators and Ligands


Chemistry

February 3, 2020
Kent 120 | Monday, 3:45 pm

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Pallab Goswami, Northwestern University

Topology of three-dimensional Dirac semimetals: a tale of SO(5) monopoles and Hopf defects

Three-dimensional massless Dirac fermions can describe the dynamics of ultra-relativistic particles, as well as the low-energy physics of emergent, gapless excitations for many solid-state systems that preserve spatial-inversion and time-reversal symmetries. Such solid-state materials are collectively known as Dirac semimetals, which support linear touching of two Kramers-degenerate bands at isolated points in momentum space. For example, the massless Dirac fermions can arise as stable excitations in Cd3As2 and Na3Bi, and also as unstable excitations at topological quantum phase transitions in bismuth-antimony alloys and indium doped bismuth selenide.


What are the bulk topological invariants of Dirac semimetals? Are the surface states of stable Dirac semimetals topologically protected? In this talk, I will provide affirmative answers to these open questions, by considering minimal models of band-structures for Dirac semimetals. These models generally involve a five-component vector field defined in momentum space, whose amplitude vanishes at Dirac points. By addressing the nature of non-Abelian SO(5) Berry’s vector potential, I will show that the topological properties of unstable and stable Dirac semimetals can be respectively understood in terms of Hopf defects and a pair of monopole and anti-monopole. I will discuss the absence of helical Fermi arcs, the precise nature of surface states, and the bulk-boundary correspondence for stable Dirac semimetals, and additional experimental consequences for many materials.
Kadanoff Seminar

February 3, 2020
MCP 201 | Monday, 1:30 pm

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Tyrel McQueen, John Hopkins University

The Materials Synthesis Frontier

Materials chemistry by design is the rational prediction and creation of functional materials with defined properties. Its goal is to meet current and future societal needs for better or more complex materials, from biocompatible materials in medicine to lightweight alloys for space applications and energy generation, storage, and transport. Unfortunately, materials chemistry has lagged other sub-fields in an extremely critical area: the ability to selectively make and break bonds in the solid state. This is due to limited synthetic methodology and method development. True materials by design cannot be achieved until reliable synthetic capabilities are developed that can actually produce the specified materials. In this talk, I will highlight the progress being made in such synthesis by design, with a particular focus on quantum materials – a class of material in which quantum phenomena not only underlie but are ‘writ large’ across macroscopic materials. Examples will range from utilizing materials discovery to test theories of the high photovoltaic performance of halide perovskites, to the development of exfoliatable quantum magnets that reveal new phenomenology as a consequence of the dimensional reduction.
Chemistry

January 31, 2020
Kent 120 | Friday, 1:45 pm

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Jessie Shelton, UIUC

Exploring the Cosmologies of Dark Sectors

One generic scenario for the dark matter of our universe is that it resides in a hidden sector: it talks to other dark fields more strongly than it talks to the Standard Model. This class of models is well-motivated by high-scale theories such as string theory, can easily accomodate the null results observed in terrestrial detectors to date, and --perhaps most importantly -- can produce a wide variety of interesting signals in both terrestrial and astrophysical observables. I'll walk through some minimal cosmological origin stories for such dark sectors and explore their consequences for where and how we might look for the footprints of dark states today.
Physics Colloquium

January 30, 2020
KPTC 106 | Thursday, 3:30 pm

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Alex Levine, UCLA

Cancelled


Computations in Science

January 29, 2020
KPTC 206 | Wednesday, 12:15 pm

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Jens Koch, Northwestern University

Intrinsically Protected Superconducting Qubits: From Concepts to Realization

The transmon qubit owes its success to robust protection from the detrimental effects of 1/f charge noise, and to its relative simplicity as one of the smallest anharmonic superconducting circuits. However, the transmon remains fully sensitive todepolarization processes, making T1 limitations an
ongoing challenge. Several proposals exist for achieving universal protection from both depolarization and dephasing in superconducting qubits - among them the 0-π qubit and the current mirror qubit. In this talk, I will present the overarching concepts of disjoint-support wavefunctions and robust ground state degeneracy, and illustrate how they emerge in concrete circuits. Following a discussion of spectra and coherence-times estimates for the 0-π qubit, I will address some of the new challenges associated with simulating and operating protected qubits. Finally, I will discuss new data on the first experimental realization of the 0-π qubit in the Houck lab. Host: Aashish Clerk, aaclerk@uchicago.edu or by phone at 4-2943 For more information please contact Alisha Manning-Beard at amannie@uchicago.edu or by phone at 4-2351.
Molecular Engineering

January 29, 2020
ERC 201B | Wednesday, 11:00 am

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Joel Yuen-Zhou, Department of Chemistry, University of Calfornia-San Diego

Polariton Chemistry: Molecules in Optical Cavities

Organic molecules interact strongly with confined electromagnetic fields in plasmonic arrays or optical microcavities owing to their bright transition dipole moments. This interaction gives rise to molecular polaritons, hybrid light-matter quasiparticles. Molecular polaritonics opens doors for new room-temperature opportunities for the nontrivial control of physico-chemical properties of molecular assemblies [1]. In this talk, I’ll showcase some of these opportunities that we have been theoretically (and, together with our experimental collaborators) exploring in the past few years. I will briefly discuss the relevant time and energy scales associated with molecular polaritons [1,2] and strategies to exploit them to control photoexcited processes including singlet fission [3], triplet harvesting [4], remote and topologically-protected energy transfer [5-7], and anomalous nonlinear optical effects [8,9,10]. Finally, I will conclude by explaining how vibrational polaritons can steer ground-state chemical reactions even in the absence of optical pumping [11], or be used to realize exotic processes such as remote control of chemical reactions [12]. Host: Suri Vaikuntanathan via email at svaikun@uchicago.edu or at 2-7256. Persons with a disability who may need assistance please contact Brenda Thomas by email at bthomas@uchicago.edu or at 2-7156.
The Tuesday JFI Seminar

January 28, 2020
GCIS W301 | Tuesday, 3:45 pm

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Connor Bischak, University of Washinton

From Solar Cells to Bioelectronics: The Interplay Between Electron and Ion Transport in Soft Semiconducting Materials


Chemistry

January 28, 2020
Kent 101 | Tuesday, 1:45 pm

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Stefano Sacanna, New York University

Engineering Colloidal Matter


Molecular Engineering

January 28, 2020
ERC 201 | Tuesday, 1:00 pm

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Brandi Cossairt, University of Washington

Interfacial Chemistry of Colloidal Nanocrystals to Direct Energy Conversion

We are interested in developing colloidal nanocrystals for wide-ranging applications in energy conversion. Our approach leverages the extraordinary properties of nanoscale systems by applying the design principles of molecular inorganic chemistry. This talk will focus on two key research themes. First, we will explore interfacial chemistry concepts to control the inner-sphere reactivity of colloidal electrocatalysts for multi-proton, multi-electron transformations. Ligand etching, ligand exchange, and covalent functionalization will be presented as complementary methods to alter electrocatalytic interfaces by tuning the activity, selectivity, and bulk interfacial properties. Second, we will explore how interfacial chemistry can be used to control the photophysics, reactivity, and assembly of colloidal semiconductor nanocrystals for emissive applications. Ultimately, we are viewing nanocrystal interfaces as platforms for coordination chemistry that will direct function.
Chemistry

January 27, 2020
Kent 120 | Monday, 3:45 pm

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Gregory Tarnopolsky, Harvard University

Origin of flat bands in Twisted Bilayer Graphene

Origin of flat bands in Twisted Bilayer Graphene, Gregory Tarnopolsky, Harvard University

Several years ago, in a continuum model of the Twisted Bilayer Graphene, a dramatic flattening of electronic low energy bands was observed numerically at a magic angle of 1.1 degrees. This theoretical discovery is believed to provide a foundation for the various interacting phenomena which were recently observed experimentally near this magic angle, including unconventional superconductivity and correlated insulators.

In this talk I will present a variant of the continuum model where the bands are exactly flat at a series of magic angles, the biggest of which is 1.1 degrees. I will exhibit an analytic derivation of this and show that the wave functions of the exactly flat band are reminiscent of the Lowest Landau Level ones. I will also discuss application of this for a construction of the Laughlin wave function in Twisted Bilayer Graphene.
Kadanoff Seminar

January 27, 2020
MCP 201 | Monday, 10:30 am

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Steven Banik, Stanford University

Hijacking the Lysosome for Targeted Protein Degradation

Multifunctional molecules have redefined how both small molecules, such as catalysts, and large biomolecules, such as cellular enzymes and receptors, can be exploited for gain-of-function processes. In the former, examples of iodoarene and hydrogen bond donor catalysts highlight how multiple functionalities can act cooperatively for asymmetric fluorination reactions and the generation of reactive cationic intermediates from stable precursors. In the latter, targeted protein degradation has emerged as a powerful strategy to address the canonically difficult-to-drug proteome enabled by multifunctional molecules. However, current technologies are limited to targets with cytosolically-accessible and ligandable domains. As the primary molecular interactors with other cells, secreted and plasma membrane proteins play direct roles in oncogenesis, immune modulation, and aging-related diseases. I will discuss how the development of conjugates capable of binding both a cell surface lysosome targeting receptor and the extracellular domain of a target protein enables degradation of secreted and transmembrane proteins from the cell surface. These lysosome targeting chimeras (LYTACs) consist of a target-binding moiety (e.g. small molecules, antibodies) fused to agonist ligands for the cation-independent mannose-6-phosphate receptor (CI-M6PR), and degrade disease-relevant proteins such as apolipoprotein E4, EGFR, and PD-L1. Mechanistic analysis of LYTAC selectivity using functional genomics revealed new cellular machinery responsible for CI-M6PR recycling, and analysis of selectivity using quantitative proteomics enabled target interactome analysis. Further in vivo work suggests unique opportunities for targeted protein degradation approaches using LYTACs. The strategy outlined here provides a blueprint for expansion of a variety of tailored multifunctional molecules to allow for selective extracellular and transmembrane protein trafficking to lysosomes.
Chemistry

January 24, 2020
Kent 102 | Friday, 1:45 pm

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a fluidic race to the bottom thwarted by diffusion

Bets, anyone?

12:00 pre-race chitchat
12:15 they're off!
MRSEC Baglunch

January 24, 2020
GCIS E123 | Friday, 12:00 pm

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Elisabeth Bik, Harbers Bik LLC

Research Misconduct - The Dark Side of Science

Science builds upon science. Even after peer-review and publication, science papers could still contain problematic data, either generated by honest errors or by intentional misconduct. If not addressed post-publication, such papers containing incorrect or even falsified data could lead to wasted time and money spent by other researchers trying to reproduce those results. Elisabeth Bik is a science integrity forensics detective who left her paid job in industry to search for misconduct in scientific papers, specializing in duplicated and manipulated images. She has done a systematic scan of 20,000 biomedical papers in 40 journals and found that about 4% of these contained inappropriately duplicated images. In her talk she will present her work and discuss several types of science misconduct.
Physics Colloquium

January 23, 2020
KPTC 106 | Thursday, 3:30 pm

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Jolene Reid, University of Utah

Data Science Tools for Selectivity Prediction in Chiral Phosphoric Acid Catalysis


Chemistry

January 23, 2020
Kent 101 | Thursday, 1:45 pm

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Rebecca Schulman, The John Hopkins University

Programming the dynamics of biomolecular material devices using coupled biomolecular reaction circuitry

Modern machinery and biological cells consist of structural components, sensors and components that compute and orchestrate a material’s behavior. Integrating sensing, functionality and molecular computation into soft and biomolecular materials could make it possible to construct active and functional devices with applications in biotechnology and biological research, the design of nanoscale devices for computing and directing efficient chemical synthesis, processing and cleanup. I will describe an approach for designing and scaling the complexity and functionality of these materials and how it is used to build self-regulating biomolecular devices that self-assemble and reconfigure and for self-healing material features. I will also describe hydrogels whose shape change is directed by DNA signals that can be used to sense proteins, small molecules and mechanical signals and in response induce specific motion programs and ongoing work to use these devices for diagnostics and to construct autonomous soft robots and new materials for tissue engineering.
Molecular Engineering

January 23, 2020
ERC 161 | Thursday, 11:00 am

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Martin Bazant, MIT

Shock Electrodialysis for Ion-Selective Water Purification

Electrochemical interfaces often undergo instabilities in shape or composition, which are notoriously difficult to control in engineering applications. The first part of this talk will describe three types of moving interfaces – viscous fingers, deionization shocks, and metal dendrites – whose stability can be controlled by electrokinetic phenomena in charged porous media, with applications to electrically enhanced oil recovery, water purification by shock electrodialysis, and energy storage in metal batteries. The second part of the talk will describe how driven electrochemical reactions can alter the thermodynamic stability of solid or liquid interfaces, with applications to Li-ion batteries, electrodeposition, and biological patterns. Finally, it will be shown that the physics of pattern formation (in these and other examples) can be learned directly from image data, by solving PDE-constrained inverse problems.
Molecular Engineering

January 22, 2020
ERC 161 | Wednesday, 2:00 pm

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Rebecca Schulman, Johns Hopkins University

Programming the dynamic behavior of biomolecular materials and nanostructures using DNA circuits and reaction networks

Biological materials operate far from equilibrium and their dynamic behavior adapts to the surrounding environment as a result of coupling to chemical, mechanical and transport processes and networks of interacting signals that interpret environmental signals and control downstream kinetics. I will describe two model systems we have developed to explore the design principles for these types of responsive materials. Engineered semiflexible filaments, DNA nanotubes, can be used understand how reaction kinetics, diffusion, and chemical reaction networks can regulate growth. Nanotubes can be assembled into structures such as bridges between molecular endpoints or hierarchical networks. DNA polymerization-induced hydrogel shape change can be directed by chemical circuits that interpret upstream signals and produce outputs that initiate a shape change response. These circuits, by amplifying chemical signals, can induce high-energy changes in material shape in response to small amounts of chemical inputs. In these hydrogels the dynamics of shape change are governed by the interplay of DNA polymerization, signal transduction, transport of oligonucleotides and water, and polymer network remodeling, many of which operate on similar time scales. I will conclude by discussing how coupling hydrogel shape change with force sensors could be used for mechanical feedback.
Computations in Science

January 22, 2020
KPTC 206 | Wednesday, 12:15 pm

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Paul Zimmerman, College of Literature, Science and the Arts, University of Michigan

Chemical Thinking in Electronic Wave Functions: The Centrality of the Bond

Chemical physics of electrons can be imagined to begin with a well-known, central type of wave function: the atomic orbital. This core idea leads to a wide array of acronymized computational theories to address interactions amongst many electrons and many atoms, especially when molecules are involved. In turn, these theories are anchored by full configuration interaction, the benchmark method that provides exact results (given a specific AO basis). Full configuration interaction is famously intractable, however, due to its massive computational cost (exponential scaling). Details hidden in this narrative, however, may guide researchers to new paths in overcoming these costs: the chemical bond contains substantial structure that can be used to organize the many-electron waves. This talk will introduce the exact electronic wave function problem, explain why it is so important to chemistry, and demonstrate a possible way to solving it in polynomial time. A new acronym will appear (iFCI) with potential for near-exact solutions to electronic energies and wave functions. Host: David Mazziotti via email at damazz@uchicago.edu or 4-1762. Persons with a disability who may need assistance please contact Brenda Thomas by email at bthomas@uchicago.edu or at 2-7156.
The Tuesday JFI Seminar

January 21, 2020
GCIS W301 | Tuesday, 3:45 pm

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Tao Xie, Zhejiang University

Dynamic Covalent Polymer Networks


Molecular Engineering

January 21, 2020
ERC 201 | Tuesday, 3:00 pm

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José Faraldo-Gómez, PhD, NHLBI, NIH

Exploring how membrane proteins influence membrane morphology and vice versa


Biophysical Dynamics

January 21, 2020
GCIS W301 | Tuesday, 12:00 pm

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Diana Iovan, University of California - Berkeley

Transition Metals at the Interface of Chemistry and Biology: Catalysis and Cell Signaling

Transition metals play central roles in numerous biological processes, participating in catalysis at active sites of metalloenzymes as well as engaging in cellular signaling events. Of note, the enzymatic C–H hydroxylation reactivity of cytochrome P450 has inspired the development of strategies for the selective and efficient conversion of hydrocarbon feedstocks into value-added products. To this end, our investigations of high-spin iron dipyrrinato complexes revealed the importance of a unique high-spin ferric iminyl electronic configuration for C–H amination processes. Studies also highlighted the access to a di-iron bridging imido that can catalytically transfer the N-group into allylic and benzylic C–H bonds. Understanding the electronic structure considerations in our systems permitted us to tune the iron dipyrrin complexes to accomplish a diastereoselective C–H amination protocol. Beyond transition metal catalysis, motivated by the implications of copper ions in diseases, we sought to elucidate the emerging role of copper in interacting with proteins and modulating enzymatic activity. To this end, we explored activitybased protein profiling approaches to identify Cu-regulated metalloproteins and proposed methods to leverage the Cu-dependency of such targets for therapeutics.
Chemistry

January 17, 2020
Kent 102 | Friday, 1:45 pm

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Having a soft side to help you grow

actin filaments have one floppy end

Meet, eat 12:00
discuss 12:15
MRSEC Baglunch

January 17, 2020
GCIS E123 | Friday, 12:00 pm

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Andreas Wallraff, ETH Zurich

Realizing Fault-Tolerant Superconducting Quantum Processors

Superconducting circuits are a prime contender both for addressing noisy intermediate-scale quantum (NISQ) problems and for realizing universal quantum computation in fault-tolerant processors. Superconducting circuits also play an important role in state of the art quantum optics experiments at microwave frequencies and provide interfaces in hybrid systems when combined with semiconductor quantum dots, color centers or mechanical oscillators. In this talk, I will discuss our experimental efforts towards realizing quantum error correction in superconducting circuits, which is an essential ingredient for reaching the full potential of fault-tolerant universal quantum computation. We pursue an approach based on the surface code in which we redundantly encode a logical qubit into a set of physical qubits. Using seven superconducting qubits, we have experimentally implemented the smallest viable instance of such a surface code, capable of repeatedly detecting any single error. We perform our experiments in a multiplexed device architecture [1], which enables fast, high fidelity, single-shot qubit readout [2], unconditional reset [3], and high fidelity single and two- qubit gates. Using ancilla-based stabilizer measurements, we initialize the cardinal states of the encoded logical qubit with high fidelity. We then repeatedly check for errors using the stabilizer readout and observe that the logical quantum state is preserved with a lifetime and coherence time longer than those of any of the constituent qubits, when no errors are detected [4]. Thus, we demonstrate an enhancement of the conditioned logical qubit coherence times beyond the coherences of its best constituent physical qubits. We are extending our current device architecture to a 17 qubit surface code, capable of not only detecting errors but also correcting errors using real-time feedback as demonstrated in our recent entanglement stabilization experiment [5].

References
[1] J. Heinsoo et al., Phys. Rev. Applied 10, 034040 (2018)
[2] T. Walter et al., Phys. Rev. Applied 7, 054020 (2017)
[3] P. Magnard et al., Phys. Rev. Lett. 121, 060502 (2018)
[4] C. Kraglund Andersen et al., arXiv:1912.09410 (2019)
[5] C. Kraglund Andersen et al., npj Quantum Information 5, 69 (2019)
Physics Colloquium

January 16, 2020
KPTC 106 | Thursday, 3:30 pm

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Joshua Buss, University of Wisconsin

Managing Redox Equivalents in Small Molecule Activation, Group Transfer, and Catalysis Madison

Small molecules are central to biological energy cycles and represent promising building blocks for commodity chemicals and solar fuels. The valorization of these feedstocks through selective transformations, however, is often challenging to control and mechanistically complex. The reduction of CO2 and CO to C≥2 products, is a topical example and is central to closing an anthropogenic carbon cycle. A series of Mo complexes, bearing a conserved terphenyl diphosphine ligand scaffold, shed light on important mechanistic aspects of both CO reductive catenation and CO2 reduction. Low temperature synthesis maps out the elementary steps by which C1 oxygenates are reduced and coupled at a single metal site; spectroscopy, kinetics, and isotopic labeling provide key insights into reaction design elements to control mechanistic branching points. Contrasting this reductive chemistry, oxidation of MoIV≡E complexes (E = N, P, C) can provide a route to productive E–E coupling. This process, germane to NH3 and H2O oxidation, is dictated by the degree of spindelocalization and radical character at the terminally bound atom. The same fundamental principles of controlling single electron transfers can be applied to catalyst speciation. Mechanistic probes highlight the importance of kinetically tuned reductants in maintaining catalyst activity in Cucatalyzed site-selective radical-relay C–H functionalization. These examples showcase that careful management of redox equivalents in both stoichiometric and catalytic reactions controls the selective (de)construction of chemical bonds, leveraging fundamental mechanistic understanding to achieve challenging transformations.
Chemistry

January 15, 2020
Kent 102 | Wednesday, 1:45 pm

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Wim van Rees, MIT

Theory, simulation, and design of thin elastic shape-shifting sheets

Recent progress in additive manufacturing and materials engineering has led to a surge of interest in shape-changing plate and shell-like structures. Such structures are typically manufactured in a planar configuration and, when exposed to an ambient stimulus such as heat or humidity, morph into their desired three-dimensional geometry. Viewed through the lens of differential geometry and elasticity, the application of the physical stimulus can be interpreted as a local change in the metric tensor field of the sheet. In this talk I will present my contributions to the theory and simulation of the sheet's elastic response to such a metric change, considering both the forward and the inverse problem. I will show how these developments have led to the design and experimental realization of a multi-material 4D printed lattice that can undergo complex, predictable 3D shape changes when subjected to a temperature difference.
Computations in Science

January 15, 2020
KPTC 206 | Wednesday, 12:15 pm

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Christopher Jarzynski, University of Maryland, College Park

The quantum adiabatic theorem governs the evolution of a wavefunction under a slowly time- varying Hamiltonian. I will consider the opposite limit of a Hamiltonian that is varied impulsively: an infinitely strong perturbation U(x,t) is applied over an infinitesimal time interval. When the strength and duration of the perturbation scale appropriately, the impulse causes the wavefunction y(x,t) to undergo a sudden displacement and/or deformation. Remarkably, this evolution is described by a purely classical construction. I will use these results to showhow tailored impulses can be used to control the behavior of a quantum wavefunction, in one or more degrees of freedom. Host: Aashish Clerk, 4-4568 or via email at aaclerk@uchicago or contact Alicia Bearden-Mannie,4-2351 or via email at amannie@uchicago.edu.
Molecular Engineering

January 15, 2020
ERC 201B | Wednesday, 11:00 am

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Cindy Regal, Department of Physics, University of Colorado-Boulder

Explorations in Cold Collisions and Magnetometry with Atoms in Optical Tweezers

Optical tweezers have become a powerful platform for individual control of single neutral atoms for quantum simulation and computing. But how does one get a single-atom source in the first place, and are there optimal ways to approach the collisional physics required to isolate a single atom? I present work in which we use a cooling technique known as grey molasses to address the complex interplay of cooling and collisional blockade physics in microscopic traps. I will also present work in which we used our optical tweezer apparatus to identify a method to extract absolute magnetic field directions using reconstruction of microwave polarization. We are now transitioning this idea to atomic vapor cells to create a sensitive and absolute vector magnetometer.Host: Aziza Suleymanzade, via email at azizas@uchicago.edu or by phone at 2-8928. Persons with a disability who may need assistance please contact Brenda Thomas by email at bthomas@uchicago.edu or at 2-7156.
The Tuesday JFI Seminar Cohosted by JFI Women in Science

January 14, 2020
GCIS W301 | Tuesday, 3:45 pm

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Philip Shushkov, California Institute of Technology

Wishing upon a star: New methods for the description of the collisional reduction of CO2 and other open quantum systems


Chemistry

January 14, 2020
Kent 101 | Tuesday, 1:45 pm

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Y. Shirley Meng, University of California San Diego

Advanced Characterization for Long Life High Energy Battery Materials

High energy long life rechargeable battery is considered as key enabling technology for deep de-carbonization. Energy storage in the electrochemical form is attractive because of its high efficiency and fast response time. Besides the technological importance, electrochemical devices also provide a unique platform for fundamental and applied materials research since ion movement is often accompanied by inherent complex phenomena related to phase changes, electronic structure changes and defect generation. In this seminar, I will discuss a few new perspectives for energy storage materials including new fast ion conductors, new intercalation compounds and their interfacial engineering. With recent advances in characterization tools and computational methods, we are able to explore ionic mobility, charge transfer and phase transformations in electrode materials in-operando, and map out the structure-properties relations in functional materials for next generation energy storage and conversion. Moreover, I will discuss a few future priority research directions for electrochemical energy storage.
Molecular Engineering

January 14, 2020
ERC 161 | Tuesday, 11:00 am

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Chris Jarzynski, University of Maryland

Scaling down the laws of thermodynamics

Thermodynamics provides a robust conceptual framework and set of laws that govern the exchange of energy and matter. Although these laws were originally articulated for macroscopic objects, nanoscale systems also exhibit “thermodynamic¬-like” behavior – for instance, biomolecular motors convert chemical fuel into mechanical work, and single molecules exhibit hysteresis when manipulated using optical tweezers. To what extent can the laws of thermodynamics be scaled down to apply to individual microscopic systems, and what new features emerge at the nanoscale? I will describe some of the challenges and recent progress – both theoretical and experimental – associated with addressing these questions. Along the way, my talk will touch on non-equilibrium fluctuations, “violations” of the second law, the thermodynamic arrow of time, nanoscale feedback control, strong system-environment coupling, and quantum thermodynamics.
Chemistry

January 13, 2020
Kent 120 | Monday, 3:45 pm

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Po-Shen Hsin, Caltech

Lorentz symmetry fractionalization and duality in (2+1)d Po-Shen Hsin, Caltech

I will introduce a new discretetransformation in quantum field theories with Z2 1-form global symmetry thatacts on line operators (point-like excitations). Then I will discussapplications to Chern-Simons matter dualities in (2+1)d.
Kadanoff Seminar

January 13, 2020
MCP 201 | Monday, 1:30 pm

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Matthew Good, PhD, Cell & Devel Biol and Bioengineering, Upenn

Sequence Determinants & Fidelity of RGG Domain Condensation to Form Membraneless Organelles

Coacervation of intrinsically disordered proteins (IDPs) commonly underlies formation of membraneless organelles, which compartmentalize molecules intracellularly in the absence of a lipid membrane. However, to date, protein coacervation cannot be predicted from primary sequence. Using a combination of predictive coarse-grained modeling, in vitro characterization and in vivo expression we characterized the chemical determinants of IDP phase separation for the disordered RGG domain from the scaffold protein LAF-1. We identified regions that have high contact probability and deletion of which significantly disrupt protein condensation in vitro and in vivo. We designed sequence variants to investigate the role of charge patterning on phase behavior and found that shuffled sequences with greater charge segregation dramatically enhances propensity to phase separate. Mutation of tyrosine to phenylalanine, or arginine to lysine, dramatically perturbed RGG phase separation, and all-atom models highlight the special role of arginine in sp2-pi interactions. Building off of this platform we are identifying chemical principles that regulate the fidelity of selective protein coacervation and prevent inappropriate mixing of disordered proteins. Finally, we demonstrate the utility of RGG-based constructs for cellular engineering. By layering enzymatic and optical regulatory handles to regulate protein solubility and valency, we can control protein condensation to form synthetic membraneless organelles in cells. Together, these studies identify key biophysical principles of RGG domain condensation, including conserved motifs, critical residues and charge patterning, while also advancing a predictive framework to identify and design sequences that phase separate.
Margaret Gardel (host).
Biophysical Dynamics

January 11, 2020
GCIS W301 | Saturday, 12:00 pm

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how DNA can alter actin's nematic defects

food-mediated self assembly: 12:00
idea mediated discussion: 12:15
MRSEC Baglunch

January 10, 2020
GCIS E123 | Friday, 12:00 pm

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Angela Olinto, University of Chicago

Space Observatories of the Highest Energy Particles: POEMMA & EUSO-SPB

What are the mysterious sources of the most energetic particles ever observed? What are the sources of energetic cosmic neutrinos? How do particles interact at extreme energies?

Building on the progress achieved by the ground-based Auger Observatory in studying cosmic particles that reach 100 EeV, an international collaboration is working on space and sub-orbital missions to answer these questions. The Extreme Universe Space Observatory (EUSO) on a super pressure balloon (SPB) is designed to detect ultra-high energy cosmic rays (UHECRs) from above. EUSO-SPB1 flew in 2017 with a fluorescence telescope. EUSO-SPB2 is being built to observe both fluorescence and Cherenkov from UHECRs and neutrinos. These sub-orbital missions lead to POEMMA, the Probe Of Extreme Multi-Messenger Astrophysics, a space mission designed to discover the sources of UHECRs and to observe neutrinos above 20 PeV from energetic transient events. POEMMA will open new Multi-Messenger windows onto the most energetic events in the Universe, enabling the study of new astrophysics and particle physics at these otherwise inaccessible energies.
Physics Colloquium

January 9, 2020
KPTC 106 | Thursday, 3:30 pm

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Ana Maria Rey, JILA and Department of Physics University of Colorado

Observation of Dynamical Phase Transitions in Cold Atomic Gases

Non-equilibrium quantum many-body systems can display fascinating phenomena relevant for various fields in science ranging from physics, to chemistry, and ultimately, for the broadest possible scope, life itself. The challenge with these systems, however, is that the powerful formalism of statistical physics, which have allowed a classification of quantum phases of matter at equilibrium does not apply.
Therefore, using controllable cold atomic systems to shed light on the organizing principles and universal behaviors of dynamical quantum matter is highly appealing. One emerging paradigm is the dynamical phase transition (DPT) characterized by the existence of a long-time-average order parameter that distinguishes two non- equilibrium phases. I will report the observation of a DPT in two different but complementary systems: a trapped quantum degenerate Fermi gas [1] and long lived arrays of atoms in an optical cavity [2]. I will show how these systems can be used to simulate iconic models of quantum magnetism with tunable parameters and to probe the dependence of their associated dynamical phases on a broad parameter space. Besides advancing quantum simulation our studies pave the ground for the generation
of metrologically useful entangled states which can enable real metrological gains via quantum enhancement.
Molecular Engineering

January 9, 2020
ERC 161 | Thursday, 11:00 am

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Eric Dufresne, ETH Zürich

The Mechanics of Soft Interfaces

Surface tension has dramatic and well-understood impacts on simple liquids. It forces small droplets to ball up, and drives liquids into narrow channels. At small scales, these interfacial forces influence a wider range of materials and pose a number of open questions.

I will describe microscopic experiments probing the interfaces of soft materials, including polymer networks and lipid bilayers. Here, the interplay of surface tension and elasticity qualitatively changes the phenomena of wetting and adhesion. First, I will describe how we exploit these effects to investigate the surface tension of soft solids. These experiments reveal fundamental differences with familiar liquid surface tension. While the surface tension of simple liquids is a constant scalar quantity, the surface tension of solids is an anisotropic and strain-dependent tensor. It is characterized not only by an interfacial energy, but also by surface shear and dilational moduli. The physical origins of these quantities are essentially unexplored. Second, I will describe new experiments investigating the adhesion of colloidal particles to lipid bilayers. Here, the competition of surface tension, bending rigidity, and interfacial energy can drive the assembly of large scale structures.
Computations in Science

January 8, 2020
KPTC 206 | Wednesday, 12:15 pm

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Eric Dufresne, ETH Zürich

Growing Droplets in Cells and Gels

To function effectively, living cells compartmentalize myriad chemical reactions. In the classic view, distinct functional volumes are separated by thin oily-barriers called membranes. Recently, the spontaneous sorting of cellular components into membraneless liquid-like domains has been appreciated as an alternate route to compartmentalization.

I will review the essential physical concepts thought to underly these biological phenomena, and outline some fundamental questions in soft matter physics that they inspire. Then, I will focus on the coupling of phase separation to elastic stresses in polymer networks. Using a series of experiments spanning living cells and synthetic materials, I will demonstrate that bulk mechanical stresses dramatically impact every stage in the life of a droplet, from nucleation and growth to ripening and dissolution.

These physical phenomena suggest new mechanisms that cells could exploit to regulate phase separation, and open new routes to the assembly of functional materials
Biophysical Dynamics

January 7, 2020
GCIS W301 | Tuesday, 12:00 pm

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Luca Delacretaz, Uchicago

Hydrodynamic Tails in CFT and the Large Delta Expansion

The late time physics of interacting Quantum Field Theories at finite temperature is controlled by hydrodynamics. For CFTs this implies that heavy operators -- which are generically expected to create thermal states -- can be studied semi-classically. I will show that hydrodynamic loops universally fix the OPE coefficients C_{HH'L}, on average, of all neutral light operators with two non-identical heavy ones, as a function of the scaling dimension and spin of the operators. These methods can be straightforwardly extended to CFTs with global symmetries, and generalize recent EFT results on large charge operators away from the case of minimal dimension at fixed charge.
Kadanoff Seminar

January 6, 2020
MCP 201 | Monday, 1:30 pm

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W. Benjamin Rogers, Brandeis University

Programming dynamic pathways to self-assembly using DNA nanotechnology

DNA is not just the stuff of our genetic code; it is also a means to build new materials. For instance, grafting DNA onto small particles can, in principle, 'program' the particles with information that tells them exactly how to put themselves together--they 'self-assemble.' Recent advances in our understanding of how this information is compiled into specific interparticle forces have enabled the assembly of crystalline phases. However, programmable assembly of other user-prescribed structures, such as aperiodic solids, liquids, or other mesophases remains elusive. Furthermore, the dynamic pathways by which DNA-based materials self-assemble are largely unknown. In this talk, I will present experiments showing that: (1) combining DNA-grafted particles with free DNA oligomers dispersed in solution can create suspensions with new types of assembly pathways; and (2) we can quantify the dynamic pathways to self-assembly, such as nucleation and growth, using a combination of microfluidics, video microscopy, and image analysis. Whenever possible, I will describe attempts to understand and model our observations using simple physical arguments.
Computations in Science

December 11, 2019
KPTC 206 | Wednesday, 12:15 pm

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John Weeks, Institute for Physical Science and Technology & Department of Chemistry and Biochemistry - University of Maryland

Solvation, Structure, and Simulations of Systems with Strong Coulomb Interactions: The Long and Short of It

ong ranged Coulomb interactions play a major role in determining the thermodynamics, structure, and dynamics of condensed phases, but present significant challenges to theory and computer simulations. Standard treatments use Ewald sums to account for distant periodic images of charges in the simulation cell. This can add significant overhead to computer simulations and hampers the development of simple local pictures and analytic theory.

Here we describe new and ongoing work using Local Molecular Field (LMF) theory to provide a unified description of nonuniform charged and polar fluids and biopolymers. LMF theory introduces a general mapping that relates the structure and thermodynamics of a nonuniform system with long-ranged Coulomb or van der Waals interactions to those of a simpler "mimic system" with effective short ranged interactions that accurately incorporate the averaged effects of the long-ranged interactions. We show that LMF theory can be viewed as a natural generalization of ideas leading to the classical van der Waals equation for uniform simple liquids like Argon.

We use LMF theory to describe the very different behavior of the cation-anion pair correlation function in dilute aqueous solutions of NaCl and CaCl2 and the hydration and association of apolar Argon and Fullerene solutes in water. This approach leads to a Short Solvent (SS) model, with truncated solvent Coulomb interactions and screened long ranged Coulomb interactions only between charged solutes. The SS model accurately describes the interplay between local hydrogen bond configurations, solute core interactions, and the long ranged dielectric screening of distant solute charges, effects that are difficult to capture in standard implicit solvent models. Host: Gregory Voth via email at gavoth@uchicago.edu or at 2-9092. Persons with a disability who may need assistance please contact Brenda Thomas by email at bthomas@uchicago.edu or at 2-7156.
The Tuesday JFI Seminar Presents The 2nd Annual Rice-Berry Lecture

December 10, 2019
GCIS W301 | Tuesday, 3:45 pm

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Francesco Paesani, University of California San Diego

Modeling Hydration, One Molecule at a Time: Realistic Computer Simulations Through Data-Driven Many-Body Models


Chemistry

December 9, 2019
Kent 120 | Monday, 3:45 pm

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Chaoming Jian, Stanford

Measurement-indeed criticality in random quantum circuits

In this talk, I will present the study of the critical behavior of the entanglement transition induced by projective measurements in (Haar) random unitary quantum circuits. I will present a replica approach that maps the calculation of the entanglement entropies in such circuits onto a two-dimensional statistical mechanics model. In this language, the area- to volume-law entanglement transition can be interpreted as an ordering transition in the statistical mechanics model. I will discuss the general scaling properties of the entanglement entropies and mutual information near the transition using conformal invariance. I will focus on a more detailed analysis in the limit of infinite on-site Hilbert space dimension in which the statistical mechanics model maps onto percolation. In particular, this analysis yields the exact value of the universal coefficient of the logarithm of subsystem size in the Rényi (including Von Neumann) entropies. I also will discuss how to access the generic transition at finite on-site Hilbert space dimension from this limit, which is in a universality class different from 2D percolation.
Kadanoff Seminar

December 9, 2019
MCP 201 | Monday, 1:30 pm

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Physics with A Bang! Holiday Lecture and JFI Open House

Students, families, teachers and especially the curious are invited to attend our annual Holiday Lecture and Open House. See fast, loud, surprising and beautiful physics demos performed by Profs. Heinrich Jaeger and Sidney Nagel. Talk to scientists about their latest discoveries. Participate in hands-on activities related to their research.

Saturday, December 7th, 2019
Kersten Physics Teaching Center
5720 S. Ellis Ave., Chicago, IL

Lecture repeated at 11am and 2pm
Open House and Demo Alley from 12pm-4pm
Lab Tours in the afternoon

Doors for the Lectures open 30 minutes before each show. Admission to this event is free. Please note: there will be no online registrations, and will be a first to arrive, first ticketed event. We do not guarantee availibility of seating, but shows will also be streamed live to alternate venues.

This event is sponsored by the James Franck Institute, the Department of Physics, the Office of the Executive Vice President for Research, Innovation and National Laboratories, and the Materials Research Science & Engineering Center. The organizer of the Open House is Prof. Sarah King.

For those needing special assistance, please send an email to ecs@uchicago.edu.
Special JFI Seminar

December 7, 2019
KPTC 106 | Saturday, 11:00 am

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Art McDonald, Queen’s University, Canada

Deep Underground Measurements in Fundamental Physics and Astrophysics

By going deep underground and creating ultra-clean detectors it is possible to address some very fundamental questions about our Universe: How does the Sun burn? What are the detailed properties of neutrinos and of the dark matter particles that make up 26% of our Universe and influence how it evolves? With the Sudbury Neutrino Observatory (SNO) we went 2 km underground to observe new properties of neutrinos that are beyond the Standard Model of Elementary Particles and also confirmed that the models of how the Sun burns are very accurate. With SNO+, we are now seeking new properties of neutrinos through measurement of the neutrino-less double beta decay of 130 Te. The Global Argon Dark Matter Collaboration is pursuing measurements at the SNOLAB (Canada) and Gran Sasso (Italy) underground laboratories with the DEAP- 3600, DarkSide-20k and Argo experiments, using liquid argon as a target for interactions by Weakly Interacting Massive Particles (WIMPs). By these measurements, we hope to push the sensitivity for detecting such potential Dark Matter particles by several orders of magnitude and perhaps observe a whole new type of matter.

Physics Colloquium

December 5, 2019
KPTC 115 | Thursday, 3:30 pm

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Irmgard Bischofberger, MIT

On Flow and Failure: Pattern Formation from Instabilities in Complex Fluids

The invasion of one fluid into another of higher viscosity is unstable in a quasi-two dimensional geometry. This viscous-fingering instability typically produces complex patterns that are characterized by repeated branching of the evolving structure. When one of the fluids is replaced by a complex fluid, the system still displays a wide range of morphologies, but their underlying mechanisms can be fundamentally altered. We explore the formation of these new patterns by considering colloidal suspensions of different concentration. (i) We sandwich a colloidal gel between two parallel plates and induce an instability at the air/gel interface by lifting the upper plate at a constant velocity. Remarkably, the viscous-fingering instability resulting from the invasion of air fingers into the gel is suppressed below a critical lift velocity and above a critical initial gap thickness. We show that the onset of the instability is determined by a critical rate of viscous energy dissipation in the gel that is proportional to the gel’s yield stress, providing a quantitative criterion for instabilities in colloidal gels. (ii) Expanding our studies to dense suspensions that exhibit discontinuous shear-thickening behavior as a response to an applied stress allows us to probe transitions from flow instabilities to fractures. Displacing a cornstarch suspension by a pressure-controlled injection of air, we observe smooth fingering in the fluid regime and different modes of fractures, ranging from slow branched cracks to single fast fractures. We discuss strategies to predict and control these different failure modes in dense suspensions.
Computations in Science

December 4, 2019
KPTC 206 | Wednesday, 12:15 pm

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Philip E. Dawson PhD, Department of Chemistry, Scripps

Chemoselective ligation - from protein engineering to DNA encoded libraries


Biophysical Dynamics

December 3, 2019
GCIS W301 | Tuesday, 4:00 pm

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Victor Galitski, Department of Physics, University of Maryland

Quantum Lyapunov Exponents

Classical chaotic systems exhibit exponential divergence of initially infinitesimally close trajectories, which is characterized by the Lyapunov exponent. This sensitivity to initial conditions is popularly known as the "butterfly effect." Of great recent interest has been to understand how/if the butterfly effect and Lyapunov exponents generalize to quantum mechanics, where the notion of a trajectory does not exist. In this talk, I will introduce the measure of quantum chaoticity – a so-called out-of-time-ordered four-point correlator (whose semiclassical limit reproduces classical Lyapunov growth), and use it to describe quantum chaotic dynamics and its eventual disappearance in the standard models of classical and quantum chaos – Bunimovich stadium billiard and standard map or kicked rotor [1]. I will describe our recent results on the quantum Lyapunov exponent in these single-particle models as well as results in interacting many-body systems, such as disordered metals [2]. The latter many-body model exhibits an interaction-induced transition from quantum chaotic to non-chaotic dynamics, which may manifest itself in a sharp change of the distribution of energy levels from Wigner-Dyson to Poisson statistics. I will conclude by formulating a many-body analogue of the Bohigas-Giannoni-Schmit conjecture. References: [1] "Lyapunov exponent and out-of-time-ordered correlator's growth rate in a chaotic system," E. Rozenbaum, S. Ganeshan, and V. Galitski, Physical Review Letters 118, 086801 (2017)
[2] "Non-linear sigma model approach to many-body quantum chaos," Y. Liao and and V. Galitski, Physical Review B 98, 205124 (2018)
The 1st Tuesday JFI Colloquium

December 3, 2019
GCIS W301 | Tuesday, 3:45 pm

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Tom Muir, Princeton University

Painting Chromatin with Synthetic Protein Chemistry


Chemistry

December 2, 2019
Kent 120 | Monday, 3:45 pm

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Gregory Falkovich, Weizmann Institute of Science

Wonders of viscous electronics

Quantum-critical strongly correlated systems feature universal collision-dominated collective transport. Viscous electronics is an emerging field dealing with systems in which strongly interacting electrons flow like a fluid. Such flows have some remarkable properties never seen before. I shall describe recent theoretical and experimental works devoted, in particular, to a striking macroscopic DC transport behavior: viscous friction can drive electric current against an applied field, resulting in a negative resistance, recently measured experimentally in graphene. I shall also describe conductance exceeding the fundamental quantum-ballistic limit, field-theoretical anomalies, freely flowing viscous currents and other wonders of viscous electronics. Strongly interacting electron-hole plasma in high-mobility graphene affords a unique link between quantum-critical electron transport and the wealth of fluid mechanics phenomena.
Kadanoff Seminar

December 2, 2019
MCP 201 | Monday, 1:30 pm

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Andrea Alu, CUNY Advanced Science Research Center

Metamaterials Based on Broken Symmetries

In this talk, I discuss our recent research activity in electromagnetics, nano-optics, acoustics and mechanics, showing how suitably tailored meta-atoms and suitable arrangements of them open exciting venues to realize new phenomena and devices for light, radio-waves and sound. I discuss venues to largely break Lorentz reciprocity and realize isolation without the need of magnetic bias, based on broken time-reversal symmetry induced by mechanical motion, spatio-temporal modulation and/or nonlinearities. I also discuss how broken symmetries in space and space-time can open the opportunity to induce topological order in metamaterials. Another class of interesting metamaterials based on broken symmetries are parity-time symmetric metamaterials, which are asymmetric in space, but symmetric upon parity and time inversion. In the talk, I will also discuss the impact of these concepts from basic science to practical technology, from classical waves to quantum phenomena. Host: Aashish Clerk at 4-4568 or via email at aaclerk@uchicago.edu. Persons needing further assistance please contact Alicia Bearden Mannie at 4-2351 or by email at amannie@uchicago.edu
Molecular Engineering

December 2, 2019
ERC 161 | Monday, 10:00 am

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Michael Murrell - Department of Physics & Biomedical Engineering

Broken Time Reversal Symmetry and the Efficiency of Biological Machines

Biological systems are driven far from equilibrium through the consumption and dissipation of energy. However, it is unclear if the quality or efficiency of a biological process is enhanced the further the system is driven from equilibrium. To address this fundamental question, we develop experimental approaches to control the consumption of energy in biological systems, and theoretical approaches to measure its dissipation. Together, we gain an understanding of the regulation of energy during the assembly and performance of biological machinery across diverse time and length-scales. At the molecular scale, we develop technologies to precisely coordinate the de novo assembly of the protein-based mechanical machinery of the cell and control its consumption of chemical energy. In doing so, we seek to mimic the physical behaviors of living cells through modulating the internal, non-equilibrium “activity”. At the mesoscopic scale, we study the physical behaviors of cells and tissues by abstracting them as driven liquids, whose behaviors are described by models of capillarity and wetting adapted to reflect activity gleaned from molecular studies. At all scales, we apply frameworks from stochastic thermodynamics to estimate dissipation and the production of entropy using phase space fluxes and the breaking of time reversal symmetry. Together, these experimental and theoretical methods can enable an understanding of the relationship between dissipation and the efficiency of biological processes. In addition, we will show how these methods provide a comprehensive description for how active stresses generated at the molecular level translate to the physical behaviors of cells and tissues, and have significant impacts on phenotypic outcomes such as cancer metastasis, and wound healing. Host: Danielle Schell, 2-8928 or via email at dscheff@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
Tuesday Seminar - JFI Women in Science

November 26, 2019
GCIS W301 | Tuesday, 3:45 pm

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Jing-Yuan Chen, Stanford

Enhanced Thermal Hall Effect in Nearly Ferroelectric Insulators

Thermal Hall measurement has become increasingly important in condensed matter physics. In the context of recent experimental observations of an unexpectedly large thermal Hall conductivity in insulating La2CuO4 and SrTiO3, collaborators and I theoretically explored conditions under which acoustic phonons can give rise to such a large thermal Hall effect. Both the intrinsic and extrinsic contributions to the thermal Hall conductivity are large in proportion to the dielectric constant and the flexoelectric coupling. While the intrinsic contribution is still orders of magnitude smaller than the observed effect, an extrinsic contribution proportional to the phonon mean free path appears likely to account for the observations, at least in SrTiO3. We predict a larger intrinsic and/or extrinsic contribution to thermal Hall effect in certain insulating perovskites. I will discuss the implications for existing and future thermal Hall experiments, as well as new theoretical problems to explore.
Kadanoff Seminar

November 26, 2019
MCP 201 | Tuesday, 1:30 pm

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David Grier Prize Minisymposium

David Grier Prize in Innovation in Biophysical Sciences Finalist Minisymposium

David Grier Prize inInnovation in Biophysical Sciences Finalist Minisymposium

Featuring

Kourtney Kroll Sosnick & Rock groups speaking on Engineering a Light Driven Molecular Motor

Wen-Hung Chou Gardel & Kovar groups speaking on Regulation of Myosin II Filament Assembly
by the Actin Cytoskeleton

Elizabeth White, Scherer & Dinner groups speaking on Correlating Insulin Granule Intracellular Dynamics & Exocytosis Using FRET Voltage Sensors
Biophysical Dynamics

November 26, 2019
GCIS W301 | Tuesday, 11:30 am

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Thomas E. Albrecht-Schmitt, Florida State University

Chemistry Beyond Plutonium: How Relativity Alters Electronic Structure in Heavy Elements


Closs Lecture

November 25, 2019
Kent 120 | Monday, 3:45 pm

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Ramis Movassagh, Cambridge Research Center

Highly entangled spin chains: Exactly solvable counter-examples to the area law

In recent years, there has been a surge of activities in proposing "exactly solvable" quantum spin chains with surprising high amount of ground state entanglement--exponentially more than critical systems that have $\log(n)$ von Neumann entropy. We discuss these models from first principles. For a spin chain of length $n$, we prove that the ground state entanglement entropy is $\sqrt(n)$ and in some cases even extensive (i.e., extensive $n$) despite the underlying Hamiltonian being: (1) Local (2) Having a unique ground state and (3) Translationally invariant in the bulk. These models have rich connections with combinatorics, random walks, Markov chains, and universality of Brownian excursions. Lastly, we develop techniques for proving the gap. As a consequence, the gap of Motzkin and Fredkin spin chains are proved to vanish as 1/n^c with c>2; this rules out the possibility of these models to be relativistic conformal field theories in the continuum limit. Time permitting we will discuss more recent developments in this direction and 'generic' aspects of local spin chains.
Kadanoff Seminar

November 25, 2019
MCP 201 | Monday, 1:30 pm

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Brainstorming about MRSEC open house

What would be your favorite goofy or awesome thing to show our young visitors on Friday December 7th? We have many hours to entertain and inspire them with hands-on demos and lab tours. What about kids who came last year and are looking for something new? Have we got enough?

What about simulations? In prior years we had stunning hands-on computer demos of chaos, critical phenomena, simulated scattering and reaction events, piling games, We probably have even better ones now. Do you have ideas?

What about everyday life science effects like how color images on a computer screen are made, or how ice becomes less slippery when it gets colder or how to ride your bike in the rain without getting mud on your back? or how to reveal the speed of fluttering leaves by analyzing a movie of a tree.

Come and bring your ideas, your pictures and your web links. _______________________
to get on this mailing list, go to
https://lists.uchicago.edu/web/info/mrsec-baglunch
MRSEC Baglunch

November 22, 2019
GCIS E123 | Friday, 12:00 pm

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Vanessa Wood, Chair, MaDe, ETH Zürich

Understanding and Optimizing Solution- Processed Systems

Solution- and slurry-processing techniques offer possibilities for scalable and low-cost manufacturing. Today, these techniques enable technologies such as lithium ion batteries and promise to play a future role in a wide variety of electronic, photonic, and electrochemical systems. Materials and devices made from these approaches often have hierarchical structures and complex interfaces. To realize the full potential of solution-processed systems, understanding structure- performance relationships is critical. In this talk, I will present examples of how my group uses neutrons, electrons, and photons to characterize structure at different length scales and to gain insights into performance limitations of solution- processed systems, including lithium ion batteries and nanocrystal-based optoelectronics. I will then describe how we apply these findings to develop design guidelines for systematic improvement of materials and devices.
Molecular Engineering

November 21, 2019
BSLC 115 | Thursday, 2:00 pm

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Rebecca Willett, University of Chicago

Leveraging physical models in machine learning

Machine learning, at its heart, is the process of learning from examples. However, in many scientific domains, we not only have training data or examples from which to learn, but also physical models of either the data collection mechanism or the underlying physical phenomenon. In this talk, I will describe two settings in which physical models can be incorporated within a machine learning framework to yield improved predictive performance. First, we will consider using training data to help solve ill-posed linear inverse problem such as deblurring, deconvolution, inpainting, compressed sensing, and superresolution. Recent advances in machine learning and image processing have illustrated that it is often possible to learn a regularizer from training data that can outperform more traditional regularizers. We will see that whether or how a forward model is leveraged can significantly impact how many training samples are needed to achieve a target accuracy. Second, we will examine using a combination of observational data and simulated data to improve subseasonal climate forecasts. Treating both types of data as co-equal training samples can bias many learning methods and yield misleading results. I will describe an alternative framework that combines observational data with a correlation graph that can be estimated from large ensemble climate model outputs, and we will see how this approach leads to more accurate forecasts. Finally, we will discuss open problems and future directions at the intersection of machine learning and the physical sciences.
Computations in Science

November 20, 2019
KPTC 206 | Wednesday, 12:15 pm

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Michael Crommie, University of California-Berkeley

Using Topology to Engineer Bottom-Up-Synthesized Graphene Nanoribbons

The idea of classifying materials by their topological properties is useful for predicting their behavior, especially at interfaces between insulators. When topologically distinct insulators are fused together then metallic states arise at the interfaces between them. This concept, which has been so fruitful in condensed matter physics for 3D and 2D materials, has recently been extended to 1D graphene nanoribbons (GNRs), which can now be classified by topology [1]. A single 0D interface between two 1D GNRs having dissimilar topology cannot support a full metallic band like higher-dimensional topological insulators, but it can generate the most basic constituent of a metal: a single, unpaired electron localized to a protected state in the GNR bandgap. By engineering multiple topological interfaces within a GNR it is thus possible to controllably position unpaired electrons that quantum mechanically interact and produce new GNR electronic and magnetic behavior. Achieving such fine topological control, however, requires the synthesis of precise, atomically-defined nanoscale interfaces. I will discuss how we have accomplished this by using new chemistry-based bottom-up synthesis techniques that enable us to build perfect interfaces between topologically distinct GNR segments. Scanning tunneling microscopy allows us to image and spectroscopically probe the resulting topologically-protected electronic states that reside at these interfaces. This technique has enabled us to engineer the band structure of semiconducting GNRs in new ways, to create metallic GNRs, and to synthesize new GNR-based quantum dot systems that are potentially useful for quantum information applications. The work I will describe lies at the boundary of condensed matter physics and organic chemistry, and is an example of the power of blending concepts from these two fields. Host: Jiwoong Park, 4-3179 or via emailjwpark@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

November 19, 2019
GCIS W301 | Tuesday, 3:45 pm

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Nigel Goldenfeld PhD, Physics, UIUC

Stochastic Turing patterns in oceans, brains & biofilms

Why are the patterns of plankton in the ocean so patchy? Why do frequently described geometrical hallucinations tend to fall into one of four different classes of pattern? Why don't we see hallucinations all the time? And why do populations in ecosystems tend to have noisy cycles in abundance? This talk explains how these phenomena all arise from the discreteness of the underlying entities, be they the on-off states of neurons or the numbers of bacteria in a fluid volume of ocean, or the number of signaling molecules in a biofilm. I explain how tools from statistical mechanics can yield insights into these phenomena, and report on a range of studies that include the operation of the primate visual cortex, the behavior of signalling molecules in a forward-engineered synthetic biofilm, and the fluctuating patterns and populations of marine organisms.
Biophysical Dynamics

November 19, 2019
GCIS W301 | Tuesday, 12:00 pm

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Latha Venkataraman, Columbia University

Quantum interference based single-molecule insulators


Chemistry

November 18, 2019
Kent 120 | Monday, 3:45 pm

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Victor-luca Iliesiu, Princeton University

Two-dimensional gravity, gauge fields and the statistical mechanics of near-extremal black holes

The low-energy behavior of near-extremal black holes can be understood from the near-horizon AdS_2 region. In turn, this region is effectively described by using Jackiw-Teitelboim gravity coupled to Yang-Mills theory. We show that such a two-dimensional model of gravity coupled to gauge fields is soluble for an arbitrary choice of gauge group and gauge couplings. Specifically, we determine the partition function of the theory on two-dimensional surfaces of arbitrary genus and with an arbitrary number of boundaries. When solely focusing on the contribution from surfaces with disk topology, we show that the gravitational gauge theory is described by the Schwarzian theory coupled to a particle moving on the gauge group manifold. Such a theory is expected to arise as the low energy limit of SYK-like models with a global symmetry. When considering the contribution from all topologies, we show that the theory is described by a novel random matrix ensemble. Finally, we compute the expectation value of various line operators in the gravitational gauge theory and describe their relationship to near-extremal black hole observables.
Kadanoff Seminar

November 18, 2019
MCP 201 | Monday, 1:30 pm

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Matthew Sigman, University of Utah

Integrating Data Science Tools into Reaction Development


AbbVie Lecture

November 15, 2019
Kent 120 | Friday, 1:45 pm

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Joseph Checkelsky, MIT

Synthesizing “Toy Model” Quantum Materials

Connecting theoretical models for exotic quantum states to real physical systems is a key goal in the study of quantum materials. Among such theoretical models, a “toy model” is one made deliberately simplistic in order to demonstrate new physical concepts and their underlying mechanisms. Such models have proven to be tremendously successful in offering insight into new condensed matter phenomena including those involving electronic topology and correlation. We describe here our recent progress in experimentally realizing “toy model” quantum materials which, in analogy to their theoretical counterparts, are designed to capture simple model systems by lattice and superlattice design. We detail developments in synthesizing and studying magnetic and superconducting materials that allow for new connections to long-standing predictions for unusual topological electronic phases. We close with a perspective for realizing further toy model systems in complex material structures.

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Physics Colloquium

November 14, 2019
KPTC 114 | Thursday, 3:30 pm

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Orit Peleg, University of Colorado

Collective Ecophysiology and Physics of Honeybees

Collective behavior of organisms creates environmental micro-niches that buffer them from environmental fluctuations e.g. temperature, humidity, mechanical perturbations etc., thus coupling organismal physiology, environmental physics and population ecology. This talk will focus on a combination of biological experiments, theory and computation to understand how a collective of bees can integrate physical and behavioral cues to attain a non-equilibrium steady state that allows them to resist and respond to environmental fluctuations of forces and flows. We analyze how honeybee clusters (Apis mellifera L.) change their shape and connectivity and gain stability by spread-eagling themselves in response to mechanical perturbations. Similarly, we study how bees in a colony respond to environmental thermal perturbations by deploying a fanning strategy at the entrance that they use to create a forced ventilation stream that allows the bees to collectively maintain a constant hive temperature. When combined with quantitative analysis and computations in both systems, we integrate the sensing of the environmental cues (acceleration, temperature, flow) and convert them to behavioral outputs that allow the swarms to achieve a dynamic homeostasis.
Computations in Science

November 13, 2019
KPTC 206 | Wednesday, 12:15 pm

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Margaret Johnson, Department of Biophysics - Johns Hopkins University

Control of Multi-Protein Self-Assembly by Membrane Localization

In diverse cellular pathways including clathrin-mediated endocytosis (CME) and viral bud formation, cytosolic proteins must self-assemble and localize to membranes. A wealth of biochemical, structural, and in vivoimaging data has provided deep insight into the seconds-to-minutes long dynamics of these self-assembly processes. Yet it is still remarkably difficult to predict how the stoichiometry of components, membrane bending, or coupling to enzymatic reactions impacts function, and this is where computational modeling can provide important insights. We recently developed novel reaction-diffusion algorithms and software that enable detailed computer simulations of nonequilibrium self-assembly over long time-scales. We have shown through theory and simulation how localization of protein binding partners to the membrane can dramatically enhance binding through dimensionality reduction, providing a trigger for assembly. As a result, we show how tuning the localization strength of proteins to the membrane, via either protein or lipid binding partners, can drive assembly and disassembly of clathrin-coated structures. This will help us to predict how the transition from early clathrin coated structures to productive vesicles is controlled in the cell. Lastly, our generalized computational methods can directly simulate a broad range of assembly processes at the cell-scale, providing a natural companion to quantitative cell biology. Host: Arvind Murugan, 4-3146 or via email at amurugan@uchicago.edu. Persons with a disability who may assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

November 12, 2019
GCIS W301 | Tuesday, 3:45 pm

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Chris Hill, PhD, Department of Biochemistry, University of Utah

Structural insights to the mechanism of Vps4 & other AAA unfoldases

Many cellular membrane fission reactions are driven by ESCRT pathways, which culminate in remodeling and disassembly of ESCRT-III polymers by the AAA ATPase Vps4. Recent advances in understanding of the budding machinery will be summarized, with special emphasis on structural studies of Vps4. These findings suggest that translocation and unfolding of substrate is achieved by a hand-over-hand mechanism in which five Vps4 subunits form a helix that is stabilized by binding ATP, while the sixth subunit of the Vps4 hexamer transitions between the ends of the five-subunit helix. The ESCRT-III substrate peptide binds in an extended (beta-strand) conformation against the five helical subunits, with its side chains binding into two arrays of binding pockets that propagate through the hexamer pore, such that each ATP hydrolysis and substrate transition results in translocation of two substrate amino acid residues. In this manner Vps4 and other AAA unfoldases, including Cdc48 and spastin, may unfold their substrate proteins by threading their polypeptide chains through a narrow pore.
Biophysical Dynamics

November 12, 2019
GCIS W301 | Tuesday, 12:00 pm

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Laura Gagliardi, University of Minnesota

Accurate Quantum Chemical Methods for Excited Electronic States and Transition-Metal Compounds


Chemistry

November 11, 2019
Kent 120 | Monday, 3:45 pm

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Yu-An Chen, Caltech

Exact bosonization in higher dimensions: from higher group bosonic SPT (symmetry protected topological) phases to Gu-Wen fermionic SPT phases.


Kadanoff Seminar

November 11, 2019
MCP 201 | Monday, 1:30 pm

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Emily Balskus, Harvard University

Deciphering the human microbiota using chemistry


Closs Lecture

November 8, 2019
Kent 120 | Friday, 1:45 pm

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Wiggling in time

Using AFM to image polymer interfacial terrain

Let's eat at 12:00
Listen and discuss at 12:15
MRSEC Baglunch

November 8, 2019
GCIS E123 | Friday, 12:00 pm

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Lars Peter Hansen, University of Chicago

Climate Change: Uncertainty and Economic Policy

Geophysicists examine and document the repercussions for the earth’s climate induced by alternative emission scenarios and model specifications. Using simplified approximations, they produce tractable characterizations of the associated uncertainty. Meanwhile, economists write simplified damage functions to assess uncertain feedbacks from climate change back to the economic opportunities for the macroeconomy. How can we assess both climate and emissions impacts, as well as uncertainty in the broadest sense, in social decision-making?

In this lecture, Lars Peter Hansen will provide a framework for answering this question by embracing recent decision theory and tools from asset pricing, and applying this structure with its interacting components in a revealing quantitative illustration. In 2013, Hansen was a recipient of the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel for his work advancing understanding of asset prices through empirical analysis. He is the director of the Macro Finance Research Program (MFR) and the David Rockefeller Distinguished Professor at the University of Chicago.

For more on “Pricing Uncertainty Induced by Climate Change,” read a reflection from Lars Peter Hansen, watch a conversation with co-author Michael Barnett or read the full paper.
Physics Colloquium

November 7, 2019
KPTC 113 | Thursday, 3:30 pm

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Anatoli Polkovnikov, Department of Physics, Boston University

Constructing Local Counterdiabatic Protocols in Complex Systems

In this talk I will discuss general idea of counterdiabatic driving allowing one to implement adiabatic protocols without usual long time constraints. The implications of such counterdiabatic driving range from designing efficient energy transfer in heat engines to quick high fidelity reparation of quantum states. While such protocols can not be exactly implemented in chaotic systems, one can design very good proxies for them and realize them without introducing additional controls using Floquet protocols. Studying an example of a specific nonintegrable spin model I will show that the generators of adiabatic transformations are highly anisotropic in the coupling space allowing one to define adiabatic flows connecting families of Hamiltonians. These flows are very reminiscent of Renormalization Group flows. I will also show that near singular (massively degenerate) points one can define special (dark) states which are very stable to adiabatic deformations. Such special states are analogous to recently discovered quantum scars. I will also mention how these ideas can be applied to construct effective low energy Hamiltonians extending the Schrieffer Wolff transformation beyond the perturbative regime. Host: Michael Levin, 2-7286 or via email to malevin@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI Special Seminar

November 6, 2019
GCIS W301 | Wednesday, 2:30 pm

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Bill Baker, Skidmore, Owings & Merrill LLP

Maxwell, Rankine, Airy and Modern Structural Engineering Design

The lecture will review some of the seminal contributions of James Clerk Maxwell, William John Macquorn Rankine and George Biddell Airy to the theory of structures and how those theories can be applied to modern structural engineering design. William F. Baker is a consulting structural engineering partner at Skidmore, Owings & Merrill LLP where he has led the structural engineering practice for more than 20 years. Bill is best known for the development of the “buttressed core” structural system for the Burj Khalifa, the world’s tallest manmade structure. In addition to his work on supertall buildings, Bill’s expertise also extends to long-span roof structures and specialty structures. He has also collaborated with numerous artists, including Jamie Carpenter, Iñigo Manglano-Ovalle, James Turrell, and Jaume Plensa. Bill is an Honorary Professor at the University of Cambridge; he has received honorary doctorates from the University of Stuttgart, Heriot-Watt University, the Illinois Institute of Technology and the University of Missouri; the Gold Medal from the Institution of Structural Engineers (IStructE), the American Society of Civil Engineers (ASCE) Lifetime Award for Design; the Gustav Magnel Gold Medal from the University of Ghent; the Fazlur Rahman Khan Medal from the Council on Tall Buildings and Urban Habitat; and the Fritz Leonhardt Preis (Germany). He is a Fellow of both the ASCE and the IStructE, and a member of the National Academy of Engineering (USA) and an International Fellow of the Royal Academy of Engineering (United Kingdom). Bill is currently collaborating with faculty members from MIT, Cambridge, ETH/Zurich, and EPFL/Lausanne on a book intended to make Maxwell’s structural engineering work accessible to the modern engineer.
Computations in Science

November 6, 2019
KPTC 206 | Wednesday, 12:15 pm

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Mehran Kardar, Department of Physics, MIT

Diversity, Tolerance, and Maturation of the Adaptive Immune Response

The adaptive immune system protects the body from the ever-changing landscape of foreign microorganisms. The two arms of the adaptive immune system, T cells and B cells, mount specific responses to pathogens by utilizing the diversity of their receptors, generated through hypermutation. T cells recognize and clear infected hosts when their highly variable receptors bind sufficiently strongly to complexes formed with antigen-derived peptides displayed on the cell surface. To avoid auto-immune responses, a process of "Thymic Selection" ensures that only self-tolerant receptors (binding weakly to self peptides) are engaged. B cells generate antibodies that strongly bind and inactivate antigens (toxic targets). Potent antibodies are generated through the process of “Affinity Maturation" which is akin to evolution at a rapid pace. Methods from Statistical Physics can be used to model and elucidate these processes, as will be demonstrated through several examples. Host(s): Suri Vaikuntanathan, 2-7256 or via email to svaikunt@uchicago.edu and Vincenzo Vitelli, 4-8829 or by at viterlli@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

November 5, 2019
GCIS W301 | Tuesday, 3:45 pm

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Masahiro Hotta, Tohoku University

Quantum Information Capsules and Generalized Partners in Condensed Matters and Quantum Fields

Entangled many-body systems and quantum fields are capable of playing a role of quantum memory storage. When unknown parameters are imprinted to one subsystem by a fixed local unitary operation, we have three different quantum pictures for storing the information, Schmidt partner (ordinary partner), generalized partner, and quantum information capsule. In the first part of this talk, we will argue a counter-intuitive phenomenon of multiple qudits. Strong chaos generated by fast scrambling at high temperature yields an ordered information storage structure with decoupled quantum information capsules. A rotational isometry emerges in quantum Fisher information matrices. In the second part of this talk, I will provide a general formula of a purification partner mode associated with a particle mode detected by a generalized Unruh-DeWitt particle detector in quantum field theory. For particle creation processes by expanding universes and moving mirrors, we will discuss how a quantum field stores information of the expanding parameter and mirror trajectories in a detected particle and its partner. The moving mirror results may be expected to be checked by future experiments in quantum optics.
Kadanoff Seminar

November 5, 2019
MCP 201 | Tuesday, 1:30 pm

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Terry Hwa, PhD, Department of Physics, University of California at San Diego

Bacterial growth laws & the origin of dimensional reduction

Extensive quantitative experiments on the model bacterium E. coli have established that many bacterial behaviors are organized in simple manners in accordance to the rate of cell growth. The existence of these simple empirical relations (growth laws) despite myriads of complex molecular interactions is a striking manifestation of a tremendous degree of dimensional reduction occurring in living cells. I will describe how the growth laws can be used to make accurate predictions of bacterial behaviors and discuss how the magic of dimensional reduction can be accomplished by bacterial cells through an ‘activity-based’ mode of gene regulation.
Biophysical Dynamics

November 5, 2019
GCIS W301 | Tuesday, 12:00 pm

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Jefferson Chan, University of Illinois, Urbana-Champaign

Expanding the Chemical Tool Box for Acoustic-based Imaging of Cancer


Chemistry

November 1, 2019
Kent 120 | Friday, 1:45 pm

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The gel that knew too much

Eat 12:00
Main event: 12:15
MRSEC Baglunch

November 1, 2019
GCIS E123 | Friday, 12:00 pm

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Zhirong Huang, Stanford University

X-ray Free-Electron Lasers: Past, Present and Future

The world’s first hard X-ray Free Electron Laser (FEL), Linac Coherent Light Source (LCLS), started its operation 10 years ago at SLAC and opened a new era of ultrafast X-ray science. The success of the LCLS inspired the worldwide development of X-ray FELs. At the present moment, LCLS is undergoing a major upgrade to provide significant enhancement in its capability. In this talk, I will describe the physical mechanism and characteristics of X-ray FELs, present some of the most exciting results in LCLS, and discuss R&D challenges for future opportunities.
Physics Colloquium

October 31, 2019
KPTC 112 | Thursday, 3:30 pm

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Lukas Muechler

Flatiron Institute, New York

In this talk I will discuss notions of how strong correlations and topology can be found in molecular systems. Motivated by the concept of Mobius aromatics in organic chemistry, I extend the recently introduced concept of fragile Mott insulators (FMI) to ring-shaped molecules with repulsive Hubbard interactions threaded by a half-quantum of magnetic flux ($hc/2e$). In this context, a FMI is the insulating ground state of a finite-size molecule that cannot be adiabatically connected to a single Slater determinant, i.e., to a band insulator, provided that time-reversal and lattice translation symmetries are preserved. I establish a duality between Hubbard molecules with $4n$ and $4n+2$ sites, with $n$ integer. A molecule with $4n$ sites is an FMI in the absence of flux but becomes a band insulator in the presence of a half-quantum of flux, while a molecule with $4n+2$ sites is a band insulator in the absence of flux but becomes an FMI in the presence of a half-quantum of flux.


Based on these results, I propose a topological classification of molecules and their chemical reactions with and without many-body interactions. I consider 0-dimensional molecular Hamiltonians in a real-space tight-binding basis with time-reversal symmetry and an additional spatial reflection symmetry. On a single particle level, the reflection symmetry gives rise to a perplectic structure which can be probed by a Wilson loop after a flux-insertion. The classification in terms of Wilson loops remains stable in the presence of many-body interactions, which can be explained by the presence of zeros of the interacting single particle Green's function. I argue that this topological classification has a universal contribution to the rate constants of chemical reactions and apply my theory to a class of reactions studied by Woodward and Hoffmann, where a reflection symmetry is preserved along a one-dimensional reaction path.
Special JFI Seminar

October 31, 2019
GCIS E123 | Thursday, 12:30 pm

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Yonggang Huang Walter P. Murphy Professor of Engineering Northwestern University

Mechanics-guided Deterministic 3D Assembly

Complex three-dimensional (3D) structures in biology form naturally to provide essential functions in even the most basic forms of life. Compelling opportunities exist for analogous 3D architectures in human-made devices, but design options are constrained by existing capabilities in materials growth and assembly. We report routes to previously inaccessible classes of 3D constructs in advanced materials, including device-grade silicon. The schemes involve geometric transformation of 2D micro/nanostructures into extended 3D layouts by compressive buckling. Designs inspired by kirigami/origami, releasable multilayers and engineered substrates enable the formation of mesostructures with a broad variety of 3D geometries, either with hollow or dense distributions. Demonstrations include experimental and theoretical studies of more than 100 representative geometries, from single and multiple helices, toroids, and conical spirals to structures that resemble spherical baskets, cars, houses, cuboid cages, starbursts, flowers, scaffolds, each with single- and/or multiple-level configurations. Morphable 3D mesostructures whoese geometries can be elastically altered can be further achieved via nonlinear mechanical buckling, by deforming the elastomer platforms in different time sequences. Compatibility with the well-established technologies available in semiconductor industries suggests a broad range of application opportunities.
Molecular Engineering

October 30, 2019
ERC 301B | Wednesday, 3:45 pm

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Ben Nachman, Lawrence Berkeley National Laboratory

Exploring hypervariate phase space with likelihood-free and label-free deep learning

Precise scientific analysis in collider-based particle physics is possible because of complex simulations that connect fundamental theories to observable quantities. These simulations have been paired with multivariate methods for many years in search of the smallest distance scales in nature. Deep learning tools hold great promise to qualitatively change this paradigm by allowing for holistic analysis of data in its natural hyperdimensionality with thousands or millions of features instead of up to tens of features. These tools are not yet broadly used for all areas of data analysis because of the traditional dependence on simulations. In this talk, I will discuss how we can change this paradigm in order to exploit the new features of deep learning to explore nature at sub-nuclear distance scales. In particular, I will show how neural networks can be used to (1) overcome the challenge of intractable hypvervariate probability density modeling and (2) learn directly from (unlabeled) data to perform hypothesis tests that go beyond any existing analysis methods. The talk will end with a brief discussion of challenges for hypervariate deep learning analysis. While my examples will be from particle physics, it is likely that these tools have a much broader applicability across fundamental physics and beyond. I will keep the particle physics jargon minimal in order to facilitate discussions about connections to your area of science!
Computations in Science

October 30, 2019
KPTC 206 | Wednesday, 12:15 pm

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Ben O'Shaughnessy, Columbia University

How Does the Actomyosin Contractile Ring Divide Cells?

Cells use actomyosin contractility for many purposes. Actomyosin-mediated forces regulate cell shape, power migration of immune cells, create cortical flows to establish cell polarity in early embryos, and power coordinated deformations during tissue morphogenesis. Among the most important and intensively studied actomyosin cellular systems is the cytokinetic contractile ring that constricts and divides cells at the end of the cell cycle during cytokinesis. This remarkable machine generates sufficient force for division, but with the right timing and constriction rate to accurately partition chromosomes to the two daughter cells. I will describe our efforts to understand the cytokinetic contractile ring in fission yeast, using computational modeling, analytical approaches and experiment. Fission yeast offers a unique opportunity for realistic experimentally-driven mathematical modeling of the ring, because many key components are biochemically characterized and their amounts measured throughout cytokinesis. Moreover, their organization is beginning to emerge from conventional and super-resolution microscopies. This talk will address several fundamental questions about this cellular machine. How does the contractile ring generate tension? How does it remain functional while shedding its parts and shortening? How do the myosin-II isoforms and other components coordinate to produce organization and force? How are contractile instabilities combatted? What sets the constriction rate, and how does this depend on tension? From theoretical analysis, experimental measurements of ring tension and a wealth of experimental background, I will argue that for fission yeast a rather unified picture emerges that answers these questions.
Host: Gregory Voth, 2-9092 or via email gavoth@uchicago.edu. Persons who need assistance please contact Brenda Thomas, 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

October 29, 2019
GCIS W301 | Tuesday, 3:45 pm

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Ray Moellering:,University of Chicago

Chemical Proteomic Platforms to Expose and Exploit Novel Metabolic Signals in Disease


Chemistry

October 28, 2019
Kent 120 | Monday, 3:45 pm

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Ron Naaman, Department of Chemical and Biological Physics, Weizmann Institute

The Relation Between Chiral Molecules and the Electron Spin - The Key to Almost Everything

Spin based properties, applications, and devices are commonly related to magnetic effects and to
magnetic materials. However, we found that chiral organic molecules act as spin filters for photoelectrons transmission, in electron transfer, in electron transport. The new effect, termed Chiral Induced Spin Selectivity (CISS), [ 1 , 2 ] was found, among others,in bio-molecules and in bio-systems. It has interesting implications for the production of new types of nano-size spintronics devices [ 3 , 4 ] and on electron transfer in biological systems. We
observed that charge polarization in chiral molecules is accompanied by spin polarization. This finding sheds new light on enantio-specific interactions and it allows to construct novel methods for enantio-separation.[ 5 ] It also opens new ways in interface-spintronics, when chiral molecules are adsorbed on semiconductor surfaces [ 6 ] or on ferromagnetic substrates.

[1] R. Naaman, Y.Paltiel, David Waldeck, Nature Reviews Chemistry 3, 250 (2019).
[2] R. Naaman, D. H. Waldeck Ann. Rev. Phys. Chem. 66, 263 (2015).
[3] O. Ben Dor, S. Yochelis, A. Radko, K. Vankayala, E. Capua, A. Capua, S.-H. Yang, L. T.
Baczewski, S. S. P. Parkin, R. Naaman, and Y. Paltiel, Nat. Comm., 8, 14567 (2017).
[4] K. Michaeli, V. Varade, R. Naaman, D. Waldeck, Journal of Physics: Condensed Matter, 29,
103002 (2017).
[5] K. Banerjee-Ghosh, O. Ben Dor, F. Tassinari, E. Capua, S. Yochelis, A. Capua, S.-H. Yang,
S. S. P. Parkin, S. Sarkar, L. Kronik, L. T. Baczewski, R. Naaman, Y. Paltiel, Science 360, 1331
(2018).
[6] E. Z. B. Smolinsky, A. Neubauer, A. Kumar, S. Yochelis, E. Capua, R. Carmieli, Y.Paltiel,
R. Naaman, K. Michaeli, J. Phys. Chem. Lett. 10, 1139 (2019).HOST: Steven J. Sibner, 2-7193 or by email to 2-sibner@uchicago.edu
JFI Special Seminar

October 28, 2019
GCIS W301 | Monday, 1:30 pm

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Jennifer Prescher, University of California, Irvine

Spying on Cellular Communication with Chemical Tools and Noninvasive Imaging

Cellular networks drive diverse aspects of human biology. Breakdowns in cell-to-cell communication also underlie numerous pathologies. While cellular interactions play key roles in human health and disease, the mechanisms by which cells transact information in vivo are not completely understood. The number of cells types involved, the timing and location of their interactions, the molecular cues exchanged, and the long-term fates of the cells remain poorly characterized in most cases. This is due, in part, to a lack of tools for observing collections of cells in their native habitats. My group is developing novel imaging probes to “spy” on cells and decipher their communications in vivo. Examples of these probes, along with their application to studies of cancer progression and host-pathogen interactions, will be discussed.
Chemistry

October 25, 2019
Kent 120 | Friday, 1:45 pm

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Donna Strickland, University of Waterloo Event Type

Generating High-Intensity, Ultrashort Optical Pulses

With the invention of lasers, the intensity of a light wave was increased by orders of magnitude over what had been achieved with a light bulb or sunlight. This much higher intensity led to new phenomena being observed, such as violet light coming out when red light went into the material. After Gérard Mourou and I developed chirped pulse amplification, also known as CPA, the intensity again increased by more than a factor of 1,000 and it once again made new types of interactions possible between light and matter. We developed a laser that could deliver short pulses of light that knocked the electrons off their atoms. This new understanding of laser-matter interactions, led to the development of new machining techniques that are used in laser eye surgery or micromachining of glass used in cell phones.
Physics Colloquium

October 24, 2019
KPTC 111 | Thursday, 3:30 pm

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David Schwab, CUNY

How noise affects the Hessian spectrum in overparameterized neural networks

Stochastic gradient descent (SGD) forms the core optimization method for deep neural networks, contributing to their resurgence. While some theoretical progress has been made, it remains unclear why SGD leads the learning dynamics in overparameterized networks to solutions that generalize well. Here we show that for overparameterized networks with a degenerate valley in their loss landscape, SGD on average decreases the trace of the Hessian of the loss. We also show that isotropic noise in the non-degenerate subspace of the Hessian decreases its determinant. In addition to explaining SGDs role in sculpting the Hessian spectrum, this opens the door to new optimization approaches that guides the model to solutions with better generalization. We test our results with experiments on toy models and deep neural networks.
Computations in Science

October 23, 2019
KPTC 206 | Wednesday, 12:15 pm

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Hanhee Paik, IBM Q - T. J. Watson Research Center

Benchmarking Quantum Computers and Future Directions for Superconducting Quantum Hardware

While the fully fault-tolerant universal quantum computing system is still many years ahead, building an early quantum computer with quantum advantage becomes a feasible near-term milestone that we can realistically plan. Increasing number of near-term applications has been accelerating the development of quantum hardware in the industries, and as quantum system size grows, we need a whole system metric to evaluate the level of hardware performance. I would like to introduce the quantum volume (arXiv:1811.12926) as a system-level metric that quantifies quantum computational power of early quantum computing processors, and will present an example of performance comparison among IBM Q public quantum processors in the cloud. The quantum volume depends on various individual component metrics such as gate fidelity and crosstalk. I will discuss some of the challenges in building superconducting quantum hardware and suggest few directions to improve the quantum volume. Host: Aziza Suleymanzade, 2-8928 or via email at azizadubna@gmail.com. Persons who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday Seminar - JFI Women in Science

October 22, 2019
GCIS W301 | Tuesday, 3:45 pm

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Johan Elf PhD, Molecular Systems Biology, Department of Cell & Molecular Biology Uppsala University, Sweden

Imaging-based live cell CRISPRi screening

Our ability to connect genotypic variation to biologically important phenotypes has been seriously limited by the gap between live cell microscopy and library-scale genomic engineering. Specifically, this has restricted studies of intracellular dynamics to one strain at a time and thus, generally, to the impact of genes with known function. I will show how in situ genotyping of a library of E. coli strains after time-lapse imaging in a microfluidic device overcomes this problem. We determine how 235 different CRISPR interference (CRISPRi) knockdowns impact the coordination of the replication and division cycles of E. coli by monitoring the location of replication forks throughout on average >500 cell cycles per knockdown. The single-cell time-resolved assay allows us to determine the distribution of single-cell growth rates, cell division sizes, and replication initiation volumes. Subsequent in situ genotyping allows us to map each phenotype distribution to a specific genetic perturbation in order to determine which genes are important for cell cycle control. I will also discuss the implications for mechanistic models of replication initiation.
Biophysical Dynamics

October 22, 2019
GCIS W301 | Tuesday, 12:00 pm

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Suri Vaikuntanathan, University of Chicago


Chemistry

October 21, 2019
Kent 120 | Monday, 3:45 pm

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Ying Lin, Caltech

Anomalies and Bounds on Charged Operators

We study the implications of 't Hooft anomaly (i.e. obstruction to gauging) on conformal field theory, focusing on the case when the global symmetry is Z2. Using the modular bootstrap, universal bounds on (1+1)-dimensional bosonic conformal field theories with an internal Z2 global symmetry are derived. The bootstrap bounds depend dramatically on the 't Hooft anomaly. In particular, there is a universal upper bound on the lightest Z2 odd operator if the symmetry is anomalous, but there is no bound if the symmetry is non-anomalous. In the non-anomalous case, we find that the lightest Z2 odd state and the defect ground state cannot both be arbitrarily heavy. We also consider theories with a U(1) global symmetry, and comment that there is no bound on the lightest U(1) charged operator if the symmetry is non-anomalous. We end with a discussion about the constraints on symmetry-protected gapless phases and introduce the notion of "category-protected gapless phases.
Kadanoff Seminar

October 21, 2019
MCP 201 | Monday, 1:30 pm

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Gregory Girolami, University of Illinois


Chemistry

October 18, 2019
Kent 120 | Friday, 1:45 pm

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Sand castles with quantum dots

Self-assemble 12:00
Self-activate 12:15
MRSEC Baglunch

October 18, 2019
GCIS E123 | Friday, 12:00 pm

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Cristina Marchetti, University of California Santa Barbara

Active Topology

In two-dimensional systems, such as thin films of superfluids, crystals, liquid crystals and magnets, topological defects are key to understanding the transition between ordered and disordered states. Almost fifty years ago, Berezinskii, Kosterlitz and Thouless showed that these systems disorder through a topological phase transition associated with the proliferation of unbound pairs of vortices of opposite charge. The essence of this transition relies on the mapping of the statistical physics of defects onto a Coulomb gas. In active liquid crystals, topological defects become motile particles and drive the transition from spontaneous laminar flow to self-sustained turbulent-like motion. In this talk I will outline the statistical physics of defects in active nematics and their possible role in materials science and biology. By viewing the active nematic as a collection of swarming and interacting active defects, the onset of active turbulence can be described as an activity-driven defect unbinding transition. A hydrodynamic theory of a gas of unbound defects captures a new state of hierarchically organized active matter - a defect flock where defects themselves line up and order into a collectively flowing liquid. The hydrodynamic treatment of active defects provides a framework to address fundamental questions of defect organization in active matter and paves the way for the design of active devices with targeted transport functionalities through the controlled variation of activity.
Physics Colloquium

October 17, 2019
KPTC 110 | Thursday, 3:30 pm

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Rebecca Kramer-Bottiglio, Yale University

From Particles to Parts—Building Multifunctional Robots with Programmable Robotic Skins

Robots generally excel at specific tasks in structured environments, but lack the versatility and adaptability required to interact-with and locomote-within the natural world. To increase versatility in robot design, my research group is developing robotic skins that can wrap around arbitrary deformable objects to induce the desired motions and deformations. Our robotic skins integrate programmable composites to embed actuation and sensing into a planar substrate that may be applied-to, removed-from, and transferred-between different objects to create a multitude of controllable robots with different functions to accommodate the demands of different environments. We have shown that attaching the same robotic skin to a deformable object in different ways, or to different objects, leads to unique motions. Further, we have shown that combining multiple robotic skins enables complex motions and functions. During this talk, I will demonstrate the versatility of this soft robot design approach by showing robotic skins in a wide range of applications - including manipulation tasks, locomotion, and wearables - using the same 2D robotic skins reconfigured on the surface of various 3D soft, inanimate objects.

Computations in Science

October 16, 2019
KPTC 206 | Wednesday, 12:15 pm

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Joerg Wrachtrup, University of Stuttgart,Germany

Nanoscale quantum sensing

The accuracy of measurements is limited by quantum mechanics. Ingenious demonstrations, like measuring gravitational fields or time have explored accuracy limits and reached fundamental obstructions. Yet, precision measurements so far are restricted to macroscale and dedicated environments.
In the talk, Prog. Wrachtrup will discuss spin quantum sensors comprising single electron spins plus a nuclear spin quantum register. With such a system we measure a variety of quantities, including electric and magnetic fields, temperature, and force. We use nuclear spins to enhance the measurement accuracy of the electron spin, serving as ancillary quantum memory bits or as quantum register for quantum Fourier transformation. Prog. Wrachtrup will present a variety of applications ranging from quantum simulations to imaging of magnetic nanostructures, precision measurements of mass changes or the structure of thin liquid layers on surfaces.

PME Distinguished Colloquium

October 16, 2019
ERC 161 | Wednesday, 11:00 am

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Dmitry Abanin, University of Geneva

Non-Equilibrium Dynamics Through the Prism of Quantum Entanglement

Remarkable experimental advances of the past decade have opened the door to probing highly non-equilibrium dynamics of quantum many-body systems. When an interacting system is prepared in a non-equilibrium state, its evolution often leads to an effective thermal equilibrium. However, as was recently demonstrated theoretical and experimentally, that there are quantum phases of matter which do not thermalize, and therefore cannot be described by statistical mechanics. In this talk, I will describe how using insights from quantum entanglement of many-body states enabled progress in understanding such phases. I will focus on three distinct mechanisms to avoid thermalization: many-body localization (MBL), the recently discovered quantum many-body scars, and frustrated glassy spin systems. Non-thermalization protects quantum coherence, leading to a wealth of new dynamical phenomena and opening attractive opportunities for controlling quantum matter.Host: Michael Levin, 2-7286 or via email to maleavin@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

October 15, 2019
GCIS W301 | Tuesday, 3:45 pm

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Stefano Sacanna, New York University

Engineering Colloidal Matter


Chemistry

October 14, 2019
Kent 120 | Monday, 3:45 pm

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Jeff McMahon, University of Michigan

Advancing CMB Cosmology: ACTPol, Simons Observatory, and CMB-S4

Measurements of the cosmic microwave background (CMB) are a powerful probe of the origin, contents, and evolution of our Universe. CMB measurements continue to improve according to a Moore’s law under which the mapping speed of experiments improves by an order of magnitude roughly every five years. This rapid progression in our ability to measure the CMB has translated into a series of scientific advances including showing our universe to be spatially flat, constraining inflationary and alternative theories of the primordial universe, and providing a cornerstone for our precision knowledge of the Lambda-CDM model. Observations with the current generation of experiments, including Advanced ACTPol, will soon produce improved cosmological constraints. Building on this work, in the coming decade Simons Observatory and ultimately CMB-S4 will: pass critical thresholds in constraints on inflation and light relativistic species; provide improved measurements of dark energy, dark matter, neutrino masses, and enable searches for new surprises.

In this talk I present the design and status of measurements with Advanced ACTPol and how we are building on this work to realize the next generations of experiments including Simons Observatory and CMB-S4. I will highlight the technological advances that underlie the rapid progress in measurements including: polarization sensitive detectors which simultaneously observe in multiple colors; metamaterial optical elements; and overall advances in experimental design. I will present preliminary new results from ACTPol and conclude with science forecasts for the coming decade.
Physics Colloquium

October 14, 2019
KPTC 109 | Monday, 3:30 pm

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Adrien Florion, EPFL

Chiral charge dynamics in Abelian gauge theories at finite temperature

he chiral anomaly present in the standard model can have important phenomenological consequences, especially in cosmology and heavyions physics. In this talk, I will focus on the contribution from the Abelian gauge fields. Despite an absence of topologically distinct sectors, they have a surprisingly rich vacuum dynamics, partly because of the chiral anomaly. I will present results obtained from real-time classical lattice simulations of a U(1) gauge field in the presence of a chiral chemical potential. They account for short distance fluctuations, contrary to effective descriptions such as Magneto-Hydrodynamics (MHD). I will discuss various phenomena, like inverse magnetic cascade, which occur in this system. In particular, in presence of a background magnetic field, the chemical potential exponentially decays. The associated chiral decay rate is related to the diffusion of the Abelian Chern-Simons number in a magnetic background, in the absence of chemical potential. The rate obtained from the simulations is an order of magnitude larger than the one predicted by MHD. If this result is shown to be robust under corrections such as Hard Thermal Loops, it will call for a revision of the implications of fermion number and chiral number non-conservation in Abelian theory at finite temperature.
Kadanoff Seminar

October 14, 2019
MCP 201 | Monday, 1:30 pm

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Out in the PSD & PME Exhibit and Speaker Series

We invite you to join us for the inaugural: OUT IN THE PSD & PME EXHIBIT & SPEAKER SERIES

Celebrating the voices of LGBTQ+ people and allies in STEM.

The exhibit will feature portraits of our community members and narratives about the often life-long process of coming out.

Opening Reception: October 11, 2019, 4 - 6pm in the ERC Atrium
Molecular Engineering

October 11, 2019
ERC Atrium | Friday, 4:00 pm

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Shinsei Ryu, University of Chicago

Holographic Quantum Matter and Entanglement Negativity

Quantum entanglement has been proven to be a key concept in condensed matter physics. It provides conceptual foundations to develop deep understanding of many-body quantum systems, and uncovers many novel phenomena in condensed matter physics. In this talk, I will discuss the entanglement negativity, a measure of quantum entanglement valid for mixed quantum states, in the context of holographic systems -- these are quantum many-body systems which admit their descriptions in terms of gravitational theory in one higher dimensions. We in particular discuss a holographic object which is dual to the entanglement negativity in holographic quantum matter.
Physics Colloquium

October 11, 2019
KPTC 108 | Friday, 3:30 pm

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Ed Bertschinger, MIT

Departments That Excel In Equity, Diversity, and Inclusion at Chicago and Across the Nation

Women and people of color are severely underrepresented in many STEM departments, especially in physical sciences and engineering. Professional societies and universities have issued reports full of recommendations, but change is slow and difficult. This talk will identify departments that are most successful in diversifying bachelor's and doctoral degrees in STEM. Using data on student and faculty demographics, departmental practices where they are known, and interviews where they are available, I will present evidence as to how successful departments in physics, engineering, and other STEM departments at Chicago, MIT, and across the nation succeed in creating environments where all students can thrive.
Physics Colloquium

October 10, 2019
KPTC 107 | Thursday, 3:30 pm

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Massimiliano Delferro, PhD., Argonne National Laboratory

Catalytic Recycling and Upcycling of Polyofins

Synthetic polymers are ubiquitous and critical to the function of modern life. However, the ubiquity of polymers has resulted in an enormous and growing amount of polymer waste, which has a long lifetime in the environment and is inefficient to recycle. Here, we have discovered Well-dispersed Pt nanoparticles supported on SrTiO3 nanocuboids by atomic layer deposition were shown to be capable of converting PE (8,000 – 158,000 Da) into value-added high-quality liquids (HQLs) by hydrogenolysis at 170 psi H2 and 300 °C under solvent-free conditions. Adsorption of PE on the catalytic surfaces plays a significant role in selective hydrogenolysis, as shown by catalytic, solid-state NMR of adsorbed 13C-enriched PE, and density functional theory. We attribute the formation of uniform low dispersity products to a combination of preferential binding of high molecular weight PE on the catalyst surface and stronger adsorption of PE to Pt than to the SrTiO3 support.
Molecular Engineering

October 10, 2019
ERC 201 | Thursday, 1:00 pm

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Broader Impacts Fair

The STEM Broader Impacts Fair provides outreach and volunteer opportunities for faculty, graduate students, and students in the College. Participants will meet organizations looking to work with scientists at every level. The 2019 Broader Impacts Fair will occur October 10 from 12-2:00 p.m. in the ERC Atrium.

If you represent an organization that offers outreach and volunteer opportunities for scientists and STEM students, please complete this form or contact Jennifer Woods at jqwoods@uchicago.edu
Molecular Engineering

October 10, 2019
ERC Atrium | Thursday, 12:00 pm

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Feng Wang, Department of Physics, University of California Berkeley

Engineering Correlation and Topology in Two-Dimensional Moire Superlattices

Van der Waals heterostructures of atomically thin crystals offer an exciting
new platform to design novel electronic and optical properties. In this talk,
I will describe how to engineer correlated and topological physics using
moire superlattice in two dimensional heterostructures. I will show that we
can realize and control extremely rich condensed matter physics, ranging
from correlated Mott insulator and superconductivity to ferromagnetism
and topological Chern insulator, in a single device featuring the ABC
trilayer graphene and boron nitride moire superlattices.
JFI Special Seminar

October 10, 2019
GCIS E123 | Thursday, 10:30 am

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Arvind Murugan, University of Chicago

Transients in physics and biology

We tend to characterize simple and complex systems in terms of their steady state properties. Transients before reaching a steady state are seen as a temporary annoyance, even in non-equilibrium systems. However, transients are all important in understanding a system in a time varying environment where the environmental changes are neither slow (adiabatic) nor fast compared to the internal dynamics of the system. We show how transients can be exploited to counter fast evolving viruses, design adaptable materials and to implement recursive Bayesian algorithms using biomolecules. Along the way, we discuss choices a physicist has in picking problems in biology and roads not taken.
Computations in Science

October 9, 2019
KPTC 206 | Wednesday, 12:15 pm

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Cory Dean, Department of Physics - Columbia University

Engineering 2D Materials With a Twist

Atomically thin crystals such as graphene, boron nitride and the transition metal dichalcogenides continue to attract enormous interest. Encompassing a wide range of properties, including single-particle, topological and correlated phenomenon, these 2D materials represent a rich class of materials in which to explore both novel physical phenomenon and new technological pursuits. By integrating these materials with one another, an exciting new opportunity has emerged in which entirely new layered heterostuctures can be fabricated with emergent properties beyond those of the constituent materials. In this talk I will discuss some of our recent efforts where, by tuning the geometry of these heterostructures at the nanoscale, we are able to realize yet a new level of control over their electronic properties. In particular I will discuss the significant role played by the rotational alignment between adjacent layers and the approach we are taking towards manipulating this degree of freedom to dynamically tune device properties in ways that are not possible with conventional materials.
Host: Jiwoong Park, 4-3179 or via email at jwpark@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu
The Tuesday JFI Seminar

October 8, 2019
GCIS W301 | Tuesday, 3:45 pm

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Sophie Dumont, PhD, Cell & Tissue Biology, UCSF

Cell Division: Mechanical Integrity with Dynamic Parts

The spindle segregates chromosomes at cell division. To perform its function, the spindle must be flexible and dynamic over short timescales, and yet maintain its architecture, integrity and function over long timescales. How it does so is poorly understood. I will begin by presenting our efforts to understand how the mammalian spindle’s steady-state architecture emerges, far from equilibrium. We show that microtubule minus-end clustering is required for the spindle to reach a steady-state geometry – and that without it the spindle becomes turbulent. I will then present our work aiming to understand ho! w the spindle’s mechanical integrity emerges from its dynamic parts. Inspired by Nicklas’ classic experiments, we pull on the mammalian spindle inside cells using microneedles, and use this approach to probe how different spindle components are dynamically connected in space and time. Looking forward, we hope that this work will inform on simple design rules that allow the spindle to be dynamic yet robust – two properties central to its function.
Biophysical Dynamics

October 8, 2019
GCIS W301 | Tuesday, 12:00 pm

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John Anderson, University of Chicago

Synthesis and Reactivity of a Terminal Co Oxo Complex


Chemistry

October 7, 2019
Kent 120 | Monday, 3:45 pm

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Anton Kapustin, Caltech

Chiral central charge and the Thermal Hall effect on the lattic

It is well-known that the zero-temperature Hall conductance of a 2d system can be interpreted both as a bulk transport coefficient and a U(1) anomaly for the edge modes. The former interpretation allows one to write down a simple formula for it (Kubo formula). The latter interpretation explains why Hall conductance is a topological invariant. In this talk I will explain the difficulties in extending these considerations to the thermal Hall conductance and how they are overcome. I will argue that the thermal Hall conductance should be regarded as an exact 1-form on the parameter space rather than a function. I will explain how to write-down a Kubo-like formula for this 1-form. Further, I show that the low-temperature thermal Hall conductance of a gapped 2d system is robust under arbitrary deformations which do not close the gap and can be identified with the chiral central charge for the edge modes. This provides the bulk-boundary correspondence for the chiral central charge.
Kadanoff Seminar

October 7, 2019
MCP 201 | Monday, 1:30 pm

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How to cook a turbulent puff using vortex rings

How does nature eat it up?

12:00 Eat. Bring a puff
12:15 See the puff motion picture
MRSEC Baglunch

October 4, 2019
GCIS E123 | Friday, 1:00 pm

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David Miller, University of Chicago

Exploring the Particle Universe at the Energy Frontier

Quarks and gluons are ubiquitous in the debris of the proton-proton collisions of the Large Hadron Collider (LHC), but they can also signal the presence of massive particles that are signs of new physics: they are the needle in the proverbial haystack…of needles. However, for the first time in the history of particle physics, the collision energy at the LHC is often well above the scale of electroweak symmetry breaking. I will walk you through why the LHC is such a fantastic “quark and gluon” machine, how new techniques to image the events observed at the LHC allow us probe jets — the observable manifestation of quarks and gluons — in exquisite detail, and present results in searching for signs of new physics using Lorentz-boosted object tagging approaches in the ATLAS Experiment. These techniques are being deployed with great success successfully in searches for new particles and precision measurements of the Standard Model, in both of which my group is deeply involved. I will then look toward the future and describe new instrumentation and algorithms that we’re developing to identify and record Lorentz-boosted hadronic objects in future runs of the LHC.
Physics Colloquium

October 3, 2019
KPTC 106 | Thursday, 3:30 pm

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Daniel Fisher, Stanford University

Evolution, Ecology, and Chaos: Questions and Simple Models

Recent observations of bacterial populations in the laboratory and in natural environments have exacerbated long-standing puzzles about evolution: Can evolution in a fixed environment continue forever? Why is there so much diversity on all scales, including coexistence of many within-species variants? A key role of theory in biology is to ask what is truly puzzling and what can already arise in simple models and thus should perhaps not be so puzzling. Some progress on these questions by statistical physics approaches will be the focus of this talk.
Computations in Science

October 2, 2019
KPTC 206 | Wednesday, 12:15 pm

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Yueh-Lin (Lynn) Loo, Ph.D., Princeton University, the Director, Andlinger Center for Energy and the Environment and Chemical & Biological Engineering Department

Making Smart Windows Smarter: symbiotic pairing of near-UV solar cells with electrochromic windows for visible light + heat management in architectural applications


Molecular Engineering

October 2, 2019
ERC 161 | Wednesday, 11:00 am

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Physical Review Editors Serena Bradde, PRE and Dario Corradini, PRX

"Ask me anything” with the Physical Review Editors

The Physical Review journals published by APS have served as the bedrock of physics research for a long time. Technological developments and a changing publishing landscape are posing challenges to long-held publishing traditions. Join this editorial session and get answers to your questions about publishing in physics from the editors for Physical Review.



The Editors: Serena Bradde (Physical Review E) received her Ph.D. from SISSA in Trieste, Italy. She did postdoctoral research at the Memorial Sloan Kettering Cancer Center (NYC), the Institut Pasteur (France), and the CUNY (NYC). She joined Physical Review E in 2016. Her expertise is in theoretical statistical and biological physics and complex systems.

Dario Corradini (Physical Review X) received his Ph.D. in computational physics from University Roma Tre, Italy. He did his postdoctoral research at Boston University and as a CNRS research fellow at Pierre and Marie Curie University (Paris) and at École Normale Supérieure. He joined PRX in 2015. His expertise include theoretical statistical physics of complex liquids and ionic materials, as well as biological and environmental physics.
Special Seminar

October 2, 2019
GCIS W301 | Wednesday, 10:00 am

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Aparna Baskaran, Department of Physics - Brandeis University

Active Matter: Applying Materials Physics Paradigm to

Active matter is a term that has come to describe diverse systems from flocking animals to the cytoskeleton of a cell. In this talk I will give an overview of the theoretical paradigm that unifies these diverse systems and discuss some results from minimal models for self propelled particles and suspension of cytoskeletal filaments. Host: Suri Vaikuntanathan, 2-7256 or via email to svaikuntanathan@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The 1st Tuesday JFI Colloquium

October 1, 2019
GCIS W301 | Tuesday, 4:00 pm

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Will Greenleaf, Stanford

Exploring the physical genome…


Biophysical Dynamics

September 30, 2019
GCIS W301 | Monday, 12:00 pm

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Closs Lecture: Professor Dr. Benjamin List: Max-Planck-Institute

Very Strong and Confined Chiral Acids: Universal Catalysts for Asymmetric Synthesis?


Closs Lecture

September 27, 2019
Kent 120 | Friday, 1:45 pm

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Boris Rybtchinski, Weizmann Institute of Science

Noncovalent Aqua Materials

Materials based on small molecules that are held together by noncovalent interactions can offer an alternative to conventional polymer materials for applications that require adaptive and stimuli-responsive features. However, it is challenging to engineer macroscopic noncovalent materials that are sufficiently robust for practical applications. We will describe our work on “aqua materials” based on well-defined organic molecules. These materials are uniquely assembled in aqueous media, where they harness the strength of the hydrophobic and π-π interactions to achieve robustness. Despite their high stability, these supramolecular systems can dynamically respond to external stimuli. We discuss design principles, fundamental properties and applications of two classes of aqua materials: (1) supramolecular gels and (2) nanocrystalline arrays. The functional materials based on them include recyclable filtration membranes for preparative nanoparticle separation, water purification and catalysis, as well as nanocrystalline films for switchable surface coatings and optoelectronic devices.

Molecular Engineering

September 25, 2019
ERC 201 | Wednesday, 11:00 am

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Bo Huang, Pharmaceutical Chemistry and Biochemistry/Biophysics, University of California, San Francisco

Mapping the inner world of cells

Cellular processes are orchestrated by a large number of biomolecules in a spatially and temporally coordinated manner within a tiny volume. To uncover the underlying organizational principles and their functional relevance, we are developing new fluorescent labeling methods and microscopy techniques to systematically map the spatial localization, temporal dynamics and activity profiles of proteins. In particular, we have developed the split fluorescent protein tagging method that allows large-scale generation of cell lines with endogenously-labeled proteins by CRISPR/Cas9-mediated gene editing. Correspondingly, we have also built a single-objective high-resolution light-sheet microscope that enables high-throughput imaging of these cell lines. These tools have led to out elucidation of how cytoplasmic protein granules formed by oncogenic kinase fusions activate Ras signaling in cancer cells.
Biophysical Dynamics

September 24, 2019
GCIS W301 | Tuesday, 12:00 pm

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Anatoly B. Kolomeisky, Rice Univerity

When Will the Cancer Start?

Cancer is a genetic disease that results from accumulation of unfavorable mutations. As soon as genetic and epigenetic modifications associated with these mutations become strong enough, the uncontrolled tumor cell growth is initiated, eventually spreading through healthy tissues. Clarifying the dynamics of cancer initiation is thus critically important for understanding the molecular mechanisms of the cancer appearance and spreading. Here we present a new theoretical approach to evaluate the dynamic processes associated with the cancer initiation. It is based on a discrete-state stochastic description of the formation of tumors as a fixation of unfavorable mutations in tissues. Using a first-passage analysis, the probabilities for the cancer to appear and the average times before it happens, which are viewed as fixation probabilities and fixation times, respectively, are explicitly calculated. It is predicted that the slowest cancer initiation dynamics is observed for neutral mutations, while it is fast for both advantageous and, surprisingly, disadvantageous mutations. The method is applied for estimating the cancer initiation times from clinical data on lifetime cancer risks for 28 different types of cancer. It is found that the higher probability of the cancer to occur does not necessary lead to the fast times of starting the cancer. This suggests that both lifetime risks and cancer initiation times must be used to evaluate the possibility of appearance of the cancer tumor. The analogy of cancer initiation processes with chemical reactions is discussed. Our theoretical analysis helps to clarify the microscopic aspects of cancer initiation processes.
Chemistry

September 23, 2019
Kent 120 | Monday, 3:45 pm

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Macropolis: A Chicagoland Polymer Symposium

Join us for this celebration of soft matter science occurring in the greater Chicago area!

This inaugural polymer science symposium is planned as the first of many of its kind. The event, to be held at the University of Chicago this year, will be hosted at Northwestern University for the next symposium.

Plenary lectures will feature faculty, postdocs, and students from both universities. Registration is free but required for lunch. For the full schedule and to register, visit the event's microsite.
Special Event

September 20, 2019
ERC 161 | Friday, 9:00 am

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Claudia Felser, Max Planck Institute Chemical Phyics of Solids

Magnetic Weyl Semimetals

Topology a mathematical concept became recently a hot topic in condensed matter physics and materials science. One important criteria for the identification of the topological material is in the language of chemistry the inert pair effect of the s-electrons in heavy elements and the symmetry of the crystal structure [1]. Beside of Weyl and Dirac new fermions can be identified compounds via linear and quadratic 3-, 6- and 8- band crossings stabilized by space group symmetries [2]. In magnetic materials the Berry curvature and the classical AHE helps to identify interesting candidates. Magnetic Heusler compounds were already identified as Weyl semimetals such as Co2YZ [3,4], in Mn3Sn [5,6,7] and Co3Sn2S2 [8,9,10]. The Anomalous Hall angle helps to identify even materials in which a QAHE should be possible in thin films. Besides
this k-space Berry curvature, Heusler compounds with non-collinear magnetic structures also possess real-space topological states in the form of magnetic antiskyrmions, which have not yet been observed in other materials [11]. Host: Peter Littlewood, 2-9879 or via email at littlewood@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
Joint JFI & PME Seminar

September 12, 2019
ERC201 | Thursday, 3:00 pm

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Efi Efrati, Weizmann Institute of Science

Rotational diffusion of a molecular cat: Fractional statistics in the harmonic three-body problem


Computations in Science

September 11, 2019
KPTC 206 | Wednesday, 12:15 pm

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Closs Lecture: Professor Zahra Fakhraai: University of Pennsylvania

Understanding Glass Transition Through Interfacial Properties


Chemistry

September 9, 2019
Kent 120 | Monday, 3:45 pm

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Alexei Tkachenko, Center for Functional Nanomaterials, Brookhaven National Laboratory

New facets of Floppy Networks: from soft matter to hard (and back).

Floppy Networks (FNs) play a prominent role in soft condensed matter physics, from polymeric gels and rubber to biomolecules, glasses, and granular materials. FNs provide valuable insight into the origin of anomalous mechanical and thermal properties in these systems. In my talk, I will discuss how the very same concept of FN emerges in the context of a family of open-framework ionic solids, which can be conceptualized as Coulomb floppy networks. One remarkable example is ScF_3. This material exhibits a number of unusual properties, including quantum structural phase transition near ambient pressure and negative thermal expansion (NTE). Our microscopic theory traces these effects to the FN-like crystalline architecture, which is stabilized by the net electrostatic repulsion that plays the role similar to the osmotic pressure in a polymeric gel. NTE in this type of inorganic solids has essentially the same origin as in gels and rubber. Our theory provides an accurate quantitative description of NTE, compressibility, and structural phase diagram, all in excellent agreement with multiple experiments. Entropic stabilization of criticality explains the observed phase behavior, while significant entropic contribution to elasticity accounts for the marked discrepancy between the experimentally observed compressibility and its ab initio calculation.



Finally (as a bonus track) I will discuss our new results in another classical problem related to FNs: the configurational entropy of a Random Closed Packing of hard spheres.
JFI Special Seminar

September 4, 2019
GCIS E123 | Wednesday, 12:00 pm

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Liquid crystal elastomer gnocchi

12:00 eat. Don't eat the gnocchi
12:15 hear about the gnocchi
MRSEC Baglunch

August 29, 2019
GCIS E123 | Thursday, 1:00 pm

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Professor Dr. Kallol Ray, Humboldt-University Berlin

Small Molecule Activation At Transition Metal Centers: Structure-Function Correlations


Chemistry

August 28, 2019
| Wednesday, 1:15 pm

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James Sellers, PhD, NHLBI, NIH

Probing the motile & mechanical properties of nonmuscle myosin 2

Three nonmuscle myosin-2 (NM2) paralogs participate in many mammalian cellular phenomena. Here we compare the mechanical properties of NM2A and NM2B. Each form 310nm bipolar filaments containing 30 myosins. The two paralogs can also co-assemble into the same filament. Both are slow enzymatically compared to most other myosins, but NM2A moves actin filaments 2 to 3 times faster than NM2B in motility assays and NM2B has a higher duty ratio. Neither NM2A nor NM2B demonstrate processive movements as single molecules. We assayed the ability of filaments of these two myosins to move processively on actin filaments bound to a cov! erslip surface. NM2B filaments move processively and experiments show that when co-polymerized with headless tail fragments about 6 motors per half filament are required for processive movements. NM2A filaments require the presence of methylcellulose to increase viscosity in order to move processively. When assayed at low loads by optical trapping NM2A and NM2B give single attachment events with lifetimes of about 1 and 3 sec, respectively. Both paralogs show load dependence of their attachment lifetimes. When actin-attached NM2A is subject to loads of 4-6 pN the lifetimes increase to ~10-20 sec. Strikingly, when NM2B molecules are subject to similar loads the attachment lifetimes are 80-300 sec. This differential load dependence may explain the role of NM2B molecules in stress fibers.
Biophysical Dynamics

August 26, 2019
GCIS W301 | Monday, 12:00 pm

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Étienne Fodor, University of Cambridge

Active matter far from equilibrium: Work, dissipation and phase transitions

Active matter is a paradigm of soft materials made of a large number of interacting agents, ranging from colonies of bacteria to assemblies of biomimetic micro-swimmers, where individual self-propulsion leads to dynamics and structures without any equilibrium equivalent. The dissipation at the basis of activity offers the opportunity to design smart materials, for instance to extract work with unprecedented protocols, for which generic guiding principles are still lacking. Moreover, controlling dissipation allows one in principle to select which order emerges at large scale, by promoting phase transitions whose properties are yet to be studied.

First, I will present design strategies for active engines which exploit specifically nonequilibrium effects, such as the autonomous motion of asymmetric obstacles and the lack of an equation of state in active fluids. I will discuss how to optimize their efficiency in terms of the protocol details and, when possible, compare their performances with thermal engines. Second, I will examine the emergence of spontaneous order when changing dissipation. Using large deviation techniques, I will describe unexpected phase transitions, for instance towards a collective motion despite the lack of aligning interactions, and rationalize the microscopic mechanisms triggering such collective effects.
MRSEC Baglunch

August 23, 2019
GCIS E123 | Friday, 1:00 pm

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Patrick McCall, PhD, Max Planck Instof Molec Cell Biol & Genetics Dresden

Measuring protein phase equilibria in situ via quantitative phase microscopy

Many membrane-less compartments in eukaryotic cells are protein-rich biomolecular condensates formed via phase separation from the cyto- or nucleoplasm. Condensate physicochemical properties, such as protein concentration, mesh size, and viscoelasticity, emerge from the interactions of the constituent molecules, and are thought to be tuned over evolutionary time to facilitate the specific biological functions of the compartments. However, a predictive understanding of how condensate properties are encoded by the amino acid sequences of scaffold proteins, which contribute the bulk of the non-aqueous condensate mass, is currently lacking. Although existing polymer physics models have provided guidance, limitations of many conventional experimental methods to accurately measure the protein concentration in the condensed phase often restricts characterization of protein condensation equilibria to the measurement of the dilute phase. This limitation severely impairs quantitative assessment of competing physical models and thereby the elucidation of the relevant biophysical picture. To address this, we use quantitative phase microscopy and optical diffraction tomography to measure the 3D refractive index distribution of protein-rich droplets following in vitro phase separation, from which we calculate the protein concentration of the condensed branch of the two-phase coexistence curve. We focus on the phase equilibria of constructs derived from TAF15, the ancestral member of the well-studied FUS/EWSR1/TAF15 protein family, and find protein concentrations in the condensed phase to typically exceed 400 mg/ml over a wide range of temperatures and ionic strengths, greatly exceeding the concentrations we estimate from confocal fluorescence microscopy. Comparison of phase diagrams of different protein constructs sheds light on the link between protein sequence and phase equilibria in vitro, providing an essential reference for experiments and perturbations in vivo.
Biophysical Dynamics

August 22, 2019
GCIS W301 | Thursday, 9:00 am

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Development of a 100 GeV tabletop particle collider…

with sound

eat, 12:00
collider: 12:15
MRSEC Baglunch

August 16, 2019
GCIS E123 | Friday, 1:00 pm

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Some like it tense

or how proteins detect osmotic load

1:00 Special guest: US
1:15 Regular guest reveals Nature's Secret
MRSEC Baglunch

August 9, 2019
GCIS E123 | Friday, 1:00 pm

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transverse shocks in an odd viscosity medium

I try to show up with the speaker at noon so whoever is there can talk

At 12:15 our discussion of transverse shocks in an odd viscosity medium would start
MRSEC Baglunch

July 26, 2019
GCIS E123 | Friday, 12:00 pm

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Nancy Forde, Department of Physics, Simon Fraser University

Interrogating protein flexibility and stability at the single-molecule level

Collagen is the fundamental structural protein in vertebrates and is widely used as biomaterial, for example as a substrate for tissue engineering. In spite of its prevalence and mechanical importance in biology, the mechanics of its triple-helical structure are surprisingly controversial: its flexibility is unresolved, as is its response to stress. My research group has been investigating these properties through single-molecule experiments. To do so, we have developed imaging algorithms to use in atomic-force microscopy, described models for polymers with inherent curvature, and built a new instrument for high-throughput single-molecule force spectroscopy, the mini-radio centrifuge force microscope (MR.CFM). I’ll describe what we have learned about collagen’s flexibility and stress response, why these properties are important, and how our work resolves some of the many contentious findings regarding collagen’s mechanics. Of broader relevance, I will also highlight potential applications of this work to other biological systems.
Biophysical Dynamics

July 19, 2019
GCIS W301 | Friday, 2:00 pm

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Graham R. Fleming

70th Birthday Symposium

Graham Fleming was born in Barrow, England on December 3,
1949. He received his B.S. with honors in Chemistry from the
University of Bristol in 1971 and his Ph.D. in physical chemistry
from University College London and the Royal Institution in
1974. Fleming held postdoctoral appointments at Caltech,
University of Melbourne, and the Royal Institution. In 1979,
Fleming joined the University of Chicago ultimately becoming the
Arthur Holly Compton Distinguished Service Professor in 1987.
At UChicago, Fleming served as Chair of the Chemistry
Department and helped found the Institute for Biophysical
Dynamics. In 1997, Fleming moved his research group to UC
Berkeley where he served as Professor of Chemistry and the
founding director of the Physical Biosciences Division at Lawrence
Berkeley National Laboratory, founding director of the California
Institute for Quantitative Biosciences (QB3), Deputy Laboratory
Director at LBNL, and Vice-Chancellor for Research.
Fleming’s research group develops and uses advanced
multidimensional ultrafast spectroscopic methods to study
complex condensed phase dynamics in systems ranging from
solvated small molecules to natural photosynthetic complexes as
well as nanoscale systems such as single-walled carbon nanotubes
and organic photovoltaics.

Program:

8:30 am Registration and Breakfast
9:00 am Welcome
9:10 am Lin Chen, ANL & Northwestern Univ.
9:55 am Tomas Mancal, Charles University in Prague
10:40 am Coffee
11:10 am Min Cho, Korea University
11:55 am Select Letters from Friends and Colleagues
12:00 pm Lunch (Atrium)
1:00 pm David Jonas, University of Colorado, Boulder
1:45 pm John Wright, University of Wisconsin, Madison
2:30 pm Coffee
3:00 pm Norbert Scherer, University of Chicago
3:45 pm Karl Freed, University of Chicago
4:15 pm Brent Kreuger, Hope College
5:00 pm Closing and Adjourn
6:00 pm Sepia (dinner by invitation)
123 North Jefferson St, Chicago

JFI Special Seminar

July 15, 2019
GCIS W301 | Monday, 8:30 am

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on leaves, flowers and seed slugs

geometry and mechanics

Meet to eat: 12:00
Stay to play: 12:15
MRSEC Baglunch

July 12, 2019
GCIS E123 | Friday, 12:00 pm

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Alfons van Blaaderen Soft Condensed Matter, Debye Institute for NanoMaterials Science, Utrecht University

Surprises in the Self-Assembly of Particles in Spherical Confinement

About 6 years ago our group started research at developing methodologies to structure matter at multiple length scales by self-assembly (SA). Presently, we see the induced SA of particles inside slowly drying droplets dispersed in an emulsion system and the resulting ​supraparticles​ (SPs) as a powerful generally applicable methodology of hierarchical SA. We found that making the shape of the particles the dominant factor in the SA is the most versatile way to use this route also for complex particle shapes and mixtures of particles. One of our first findings by both experiments and computer simulations was that spherical particles self-assembled inside a spherical confinement do not have their equilibrium bulk face centered cubic, close packed, crystal arrangement, but instead adopt an ​icosahedral​ symmetry. It turns out this icosahedral symmetry is the lowest free energy state up until roughly 100.000 particles [1]. Icosahedral packings are known not to be able to regularly pack in 3D space and are known e.g. for clusters of atoms interacting through a Lennard-Jones potential. However, it was not known that shape and thus entropy alone would favor this symmetry as well when it is induced by the spherical confinement. In recent work, we have extended our results to include the effects of particles shape (e.g. using rounded cube shaped particles) [2], rod-shaped particles [3], plate-shaped and binary particle systems. We will discuss how these changes affect the SA and how such SPs can be analyzed quantitatively on the single particle level in 3D by electron microscopy tomography [1-4]. We will also show our first more applied work on creating SPs with tunable light emission [5,7], for which the emission properties are modified by Mie Whispering Gallery Modes [6], and that are able to lase as well [7]. For a binary mixture of hard particles that form so-called MgZn​2​ Laves Phase crystals in bulk we find 3D icosahedral quasicrystals to be induced by the spherical confinement (unpublished work [8]) allowing us for the first time to determine on the single particle level in 3D the structure of a quasicrystal and with computer simulations study how these systems nucleate and grow.
JFI Special Seminar

July 3, 2019
KPTC 206 | Wednesday, 10:30 am

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Cristina Paulino, PhD, Department of Structural Biology & Enzymology Groningen Biomolecular Sciences & Biotechnology Institute (GBB) University of Groningen

Cryo-EM studies on membrane transporters reveal new mechanistic insights


Biophysical Dynamics

July 2, 2019
GCIS W301 | Tuesday, 12:00 pm

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Nanoparticle Templating of Ultra-thin and Highly Porous Polymer Membranes

12:00 eating time
12:15 Science time
MRSEC Baglunch

June 28, 2019
GCIS E123 | Friday, 12:00 pm

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Dr. Peter S. Burns, Department of Physics, University of Colorado-Boulder

Towards Quantum Transduction with an Improved Electro-Opto-Mechanical Converter

A quantum link between microwave and optical frequencies is a crucial element of future quantum networks. We have developed an efficient electro-optic converter by coupling a single vibrational mode of a SiN membrane to both a superconducting microwave resonator and a high-finesse optical cavity. This converter operates at T < 100 mK temperatures with 47% conversion efficiency. Discovering that vibrational noise produces correlations between microwave and optical outputs, we implement a classical feedforward protocol that improves the recovery of a weak, upconverted signal and reduces added noise by 59%, to 38 photons, for this high-efficiency device. Our results introduce an intriguing alternative method for handling errors introduced by thermal noise. The main contributions to this added noise are thermally driven mechanical motion, undesired interactions between the laser and the superconducting circuit, and microwave circuit parameter noise. In order to address these sources of noise, we have redesigned the optical cavity, introduced phononic shielding, and fabricated the superconducting circuit from NbTiN instead of Nb. With these design innovations we hope to reduce the added noise below the one photon threshold for quantum operations.


JFI Special Seminar

June 26, 2019
GCIS E223 | Wednesday, 11:00 am

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Supercritical Water

from universality to personality

Meet to eat: 12:00
Listen and discuss: 12:15
MRSEC Baglunch

June 21, 2019
GCIS E123 | Friday, 12:00 pm

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IBD Science@theInterface

Machine Learning in Biology

The 15th Annual IBD Science@theInterface is scheduled for this FRIDAY, JUNE 21st.
The symposium’s theme this year is “Machine Learning in Biology” and will be held in the Knapp Center for Biomedical Discovery, Room 1103, beginning at 10:30.
The speakers will cover a wealth of topics, with something for everyone, schedule below. The talks will followed by a reception for all symposium attendees.


Welcome, Michael Rust
Session 1, Benoit Roux, Moderator
10:30-11:15
Pratyush Tiwary, University of Maryland, College Park
Learning to learn: accurate, efficient sampling of (bio)molecular rare events

11:15-12:00
Ishanu Chattopadhyay, University of Chicago
Reverse-engineering Stochastic Dynamics: Quasi-species Evolution, Complex Disease Processes and Beyond

12:00-1:00 lunch (will be provided)

Session 2, Mike Rust, Moderator
1:00-1:45
Aly Azeem Khan, Toyota Technological Institute at Chicago
New computational approaches to understand immune function

1:45-2:30
Christina Leslie, Sloan Kettering Institute
Decoding chromatin states in immune and cancer cells

2:30-3:00 break

Session 3, Arvind Murugan, Moderator
3:00-3:45
Mona Singh, Princeton University
Integrative approaches to discover cancer genes

3:45-4:3
Loïc Royer, Chan Zuckerberg Biohub
Pushing the Limits of Fluorescence Microscopy with adaptive imaging and machine learning

4:30 Reception
Biophysical Dynamics

June 21, 2019
KCBD 1103 | Friday, 10:30 am

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Matt Jaffe, University of California, Berkeley

Atom interferometry in an optical cavity

Matter wave interferometry has become a powerful tool for precision measurement and metrology. Optical resonators, meanwhile, are a ubiquitous tool for the coherent control of light. We have combined these two components to build the first atom interferometer inside of an optical cavity. I will present techniques and measurements enabled by and performed with this apparatus. The resonant power enhancement and mode-filtering of the cavity provide strong, smooth wavefronts for manipulating atoms. Very recently, this has led to record-breaking interferometer durations of up to 15 seconds using an optical lattice. It has also enabled a high-fidelity adiabatic passage technique which allows for coherent momentum transfer of up to hundreds of photons. We have used this cavity atom interferometer to explore three types of interactions with an in-vacuum source mass: (i) gravity, (ii) a novel force mediated by blackbody radiation, and (iii) "screened" forces arising from certain dark energy models. I will discuss each of these topics, as well as an outlook for future applications.
JFI Special Seminar

June 17, 2019
GCIS E223 | Monday, 3:30 pm

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Thomas Chalopin, Collège de France

Light-spin interactions in atomic dysprosium: non-classical spin states and synthetic dimensions

The combination of a large spin J = 8 and narrow optical transitions makes bosonic dysprosium an ideal platform for engineering strong light-spin interactions. In our experiments, we use off-resonant laser beams close to the intercombination line at 626 nm to induce non-linear spin coupling in the electronic ground state of dysprosium.

In the first part of this talk, I will describe the implementation of the celebrated one-axis twisting Hamiltonian [Kitagawa et. al., PRA 47 5138 (1993)]. We experimentally realize a superposition of coherent spin-states with opposite magnetizations, that we call a 'kitten' state. We show that this highly sensitive state can be used in the context of quantum metrology, and we experimentally measure an enhanced sensitivity to external magnetic field by a factor 13.9(1.1), close to the Heisenberg limit G = 2J = 16. We also show that the combination of single magnetic sublevel resolution and arbitrary spin rotations enables us to measure the optimal sensitivity of non-gaussian (oversqueezed) states, well above the capability of squeezed states, and more robust to environmental noise than superposition states.


In the second part of the talk, I will discuss the realization of synthetic Landau levels using dysprosium atoms. A synthetic spatial dimension is encoded in the large spin of dysprosium, and additional spin-orbit coupling yields to the emergence of an artificial gauge field. In an analogy with a charged particle in an external magnetic field, the low-energy spectrum of our system exhibits the same characteristics as Landau levels. Although our experimental results are still preliminary, we are able to probe the main features of the Lowest Landau level: propagating edge modes, closed cyclotron orbits and the emergence of an anomalous velocity.
JFI Special Seminar

June 17, 2019
GCIS E223 | Monday, 1:15 pm

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Niklas Mueller, Brookhaven National Laboratory

Constructing phase space distributions with internal symmetries

We discuss an ab initio world-line approach to constructing phase space distributions in systems with internal symmetries. Starting from the Schwinger-Keldysh real time path integral in quantum field theory, we derive the most general extension of the Wigner phase space distribution to include color and spin degrees of freedom in terms of dynamical Grassmann variables. The corresponding Liouville distribution for colored particles, which obey Wong's equation, has only singlet and octet components, while higher moments are fully constrained by the Grassmann algebra. The extension of phase space dynamics to spin is represented by a generalization of the Pauli-Lubanski vector; its time evolution via the Bargmann-Michel-Telegdi equation also follows from the phase space trajectories of the underlying Grassmann coordinates. Our results for the Liouville phase space distribution in systems with both spin and color are of interest in fields as diverse as chiral fluids, finite temperature field theory and polarized parton distribution functions. We also comment on the role of the chiral anomaly in the phase space dynamics of spinning particles. Our formulation may be extended to a generating functional for hydrodynamics with internal symmetries, relevant for chiral fluids in QCD and beyond.
Kadanoff Seminar

June 10, 2019
PRC 201 | Monday, 1:30 pm

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Aishwarya Kumar, Penn State University

Neutral atom quantum computing: Quantum gates and Maxwell's demon

Atoms trapped in optical lattices are promising qubit candidates for quantum computers. I will describe the control that we have developed over the internal and motional states, as well as the positions of Cesium atoms trapped in a 3D optical lattice. We can execute arbitrary, site-selective single qubit gates with high fidelity (0.996) and low crosstalk (0.002). Initially, only a random half of the lattice sites are occupied with a single atom due to pairwise light assisted collisions. After cooling to the 3D vibrational ground state of the trap, most of the entropy is associated with this random occupation of the lattice. I will show how we move single atoms to generate fully filled sub-lattices, significantly lowering the entropy and creating a desirable starting point for a quantum computation. This “sorting” process is also an implementation of a Maxwell’s demon. I will also outline the path to implementing high fidelity entangling gates in this system and realize a 50 qubit quantum computer in the near future.


JFI Special Seminar

June 10, 2019
GCIS E223 | Monday, 11:00 am

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Critical exceptional point:

From Bose-Einstein condensate to active matter

Eat and kibitz: 12:00
Listen and kibitz: 12:15
MRSEC Baglunch

June 7, 2019
GCIS E123 | Friday, 12:00 pm

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David Saltzberg, University of California Los Angeles

How did Amy and Sheldon win their Nobel Prize?

Since 2006, I worked with the writers and other crew of the television situation comedy, The Big Bang Theory which just aired its season finale. I will talk about my experiences putting my University of Chicago physics PhD to work helping the writers and others tell this story as their "science consultant." Along the way, I've learned that comedy is an empirical subject. I'll share a few of the other things I learned about working with creative and dedicated people in an industry seemingly far from my own.
Physics Colloquium

June 6, 2019
KPTC 106 | Thursday, 3:30 pm

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Shantanu Mundhada, Yale University

The susceptibility of quantum information to decoherence makes error correction an important area of research. However, the majority of quantum error correction protocols are accompanied by a significant hardware and software overhead. One way to mitigate the overhead is by hardware-efficient encoding and autonomous error correction. For superconducting quantum circuits, this goal can be achieved by storing information in high-Q harmonic oscillators, using Schrödinger cat-states. This encoding requires a highly nonlinear, six-quanta process for autonomously stabilizing the manifold of quantum information. I will present theory and experimental results on obtaining the eight-wave mixing nonlinearity using Raman-assisted cascading of four-wave mixing processes. I will also present a circuit design for cancelling unwanted Hamiltonian terms, like cross-Kerr interactions, which introduce uncorrected errors in our code space. We believe this combination of Hamiltonian engineering and hardware design will result in a completely error protected logical qubit.
JFI Special Seminar

June 6, 2019
GCIS E223 | Thursday, 1:30 pm

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IME Distinguished Colloquium Series - Ralph Colby

Professor Ralph Colby from Penn State University will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

June 5, 2019
KCBD 1103 | Wednesday, 4:00 pm

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Atac Imamoglu, ETH Zurich

Many-body Optical Excitations in Solid-State Systems

Two dimensional materials provide new avenues for synthesizing compound quantum systems. Monolayers
with vastly different electric, magnetic or optical properties can be combined in van der Waals
heterostructures which ensure the emergence of new functionalities; arguably, the most spectacular example
to date is the observation of strong correlations and low electron density superconductivity in Moire
superlattices obtained by stacking two monolayers with a finite twist angle. Optically active monolayers such
as molybdenum diselenide provide a different "twist" as they allow for investigation of nonequilibrium
dynamics in van der Waals heterostructures by means of femtosecond pump-probe measurements. Moreover,
interactions between electrons and the elementary optical excitations such as excitons or polaritons, provide
an ideal platform for investigation of quantum impurity physics, with possibilities to probe both Fermi- and
Bose-polaron physics as well as mixtures with tunable density of degenerate fermions and bosons.
After introducing the framework we use to describe many-body optical excitations in van der Waals
heterostructures, I will describe two recent developments in the field. The first experiment uses pump-probe
measurements to demonstrate how exciton-electron interactions beyond the non-self-consistent T-matrix
approximation lead to optical gain by stimulated cooling of exciton-polaron-polaritons. The second experiment shows that a tri-layer system, consisting of two semiconducting monolayers separated by an insulating layer, could lead to hybridization of intra- and inter-layer excitons. The latter has potentialapplications ranging from strongly interacting polaritons to reaching Feshbach resonance condition in exciton-electron scattering.Host: Jonathan Simon, 2-9661 or via email at simonjon@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The 1st Tuesday JFI Colloquium

June 4, 2019
GCIS W301 | Tuesday, 4:00 pm

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Carlos Bustamante: University of California,Berkeley

Division of Labor Among the Subunits of a Highly Coordinated Ring ATPase

Many transport processes in the cell are performed by a diverse but structurally and functionally related family of
proteins. These proteins, which belong to the ASCE (Additional Strand, Conserved E) superfamily of ATPases, often form
mutimeric rings. Despite their importance, a number of fundamental questions remain as to the coordination of the
various subunits in these rings. Bacteriophage phi29 packages its 6.6 mm long double-stranded DNA using a pentameric
ring nano motor This portal motor is ideal to investigate these questions and is a remarkable machine that must
overcome entropic, electrostatic, and DNA bending energies to package its genome to near-crystalline density inside the
capsid. Using optical tweezers, we find that this motor can work against loads of up to ~55 picoNewtons on average,
making it one of the strongest molecular motors ever reported. We establish the force-velocity relationship of the
motor. Interestingly, the packaging rate decreases as the prohead fills, indicating that an internal pressure builds up due
to DNA compression attaining the value of ~3 MegaPascals at the end of packaging. This pressure, we show, is used as
part of the mechanism of DNA injection in the next infection cycle. We have used high-resolution optical tweezers to
characterize the steps and intersubunit coordination of the pentameric ring ATPase responsible for DNA packaging in
bacteriophage Phi29. By using non-hydrolyzable ATP analogs and stabilizers of the ADP bound to the motor, we establish
where DNA binding, hydrolysis, and phosphate and ADP release occur relative to translocation. Surprisingly, a division
of labor exists among the subunits: while only 4 of the subunits translocate DNA, all 5 bind and hydrolyze ATP,
suggesting that the fifth subunit fulfills a regulatory function. Furthermore, we show that the motor not only can
generate force but also torque. We characterize the role played by the special subunit in this process and identify the

symmetry-breaking mechanism in the motor. Finally, we have begun to investigate the physical basis of the inter-
subunit communication that results in this almost “clockwork” coordination. Mutants of the crucial arginine finger

residue permit us to dissect the network of interactions involved in this coordination.
Harkins Lecture

June 4, 2019
Kent 120 | Tuesday, 1:45 pm

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Carlos Bustamante: University of California,Berkeley

The Ribosome Modulates Nascent Protein Folding and Nascent Protein Folding can Modulate the Ribosome ActivityThe Ribosome Mandates Nascent Protein Folding and Nascent

Proteins are synthesized by the ribosome and generally must fold to become functionally active. Although it is commonly assumed that the ribosome affects the folding process, this idea has been extremely difficult to demonstrate. We optical tweezers to investigate the folding of single ribosome-bound stalled nascent polypeptides of T4 lysozyme synthesized in a reconstituted in vitro translation system. Significantly, we find that the ribosome slows the formation of stable tertiary interactions and the attainment of the native state relative to the free protein. Incomplete T4 lysozyme polypeptides misfold and aggregate when free in solution, but they remain folding-competent near the ribosomal surface. These results suggest that the ribosome not only decodes the genetic information and synthesizes polypeptides, but also promotes efficient de novo attainment of the native state. On the other hand, interactions between the nascent polypeptide and the ribosome exit tunnel represent one mode of regulating synthesis rates. The SecM protein arrests its own translation, and release of arrest at the translocon has been proposed to occur by mechanical force. Using optical tweezers, we demonstrate that arrest of SecM-stalled ribosomes can indeed be rescued by force alone and that the force needed to release stalling can be generated in vivo by a nascent chain folding near the ribosome tunnel exit. We formulate a kinetic model describing how a protein can regulate its own synthesis by the force generated during folding, tuning ribosome activity to structure acquisition by a nascent polypeptide.
Harkins Lecture

June 3, 2019
Kent 120 | Monday, 1:45 pm

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Amos Yaron, Technion

Probing anomalous driving

I will describe two novel effects that may be observed once one drives a system whose underlying matter content generate an ’t Hooft anomaly. The effects are tied to the existence of quasi-normal modes of magnetically charged black branes at low temperatures and to features of Chern-Simons Maxwell dynamics in an asymptotically AdS geometry.
Kadanoff Seminar

June 3, 2019
PRC 201 | Monday, 1:30 pm

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David Sussillo, Google

Universality and individuality in neural dynamics across large populations of recurrent networks

Currently neuroscience is undergoing a data revolution, where many thousands of neurons can be measured at once. These new data are extremely complex and will require a major conceptual advance in order to infer the underlying brain computations from them. In order to handle this complexity, systems neuroscientists have begun training deep networks, in particular recurrent neural networks (RNNs), in order to make sense of these newly collected, high-dimensional data. These RNN models are often assessed by quantitatively comparing neural dynamics of the model with the brain. However, the nature of the detailed neurobiological inferences one can draw from such comparisons remains elusive. For example, to what extent does training RNNs to solve simple tasks, prevalent in neuroscientific studies, uniquely determine the low-dimensional dynamics independent of neural architectures? Or alternatively, are the learned dynamics highly sensitive to different neural architectures? Knowing the answer to these questions has strong implications on whether and how to use task-based RNN modeling to understand brain dynamics. To address these foundational questions, we study populations of thousands of RNN architectures commonly used to solve neuroscientifically motivated tasks and characterize their dynamics. We find the geometry of the dynamics can be highly sensitive to different network architectures. Moreover, we find that while the geometry of neural dynamics can vary greatly across architectures, the underlying computational scaffold: the topological structure of fixed points, transitions between them, limit cycles, and aspects of the linearized dynamics, often appears universal across all architectures. Overall, this analysis of universality and individuality across large populations of RNNs provides a much needed foundation for interpreting quantitative measures of dynamical similarity between RNN and brain dynamics.
Physics Colloquium

May 30, 2019
KPTC 106 | Thursday, 3:30 pm

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Xiaoming Mao, University of Michigan

Topological floppy modes in aperiodic networks and a mechanical duality theorem

Topological states of matter have been intensively studied in crystals, leading to fascinating phenomena such as scattering-free edge current in topological insulators. However, the power of topological protection goes well beyond ordered crystal lattices. In this talk we explore how topology protects mechanical edge modes in messy, noncrystalline, systems. We will use disordered fiber networks and quasicrystals as our examples, to demonstrate how topological edge floppy modes can be induced in these structures by controlling their geometry. Fiber networks are ubiquitous in nature and especially important in bio-related materials. Establishing topological mechanics in fiber networks may shed light on understanding robust processes in mechanobiology. Quasicrystals show unusual orientational order with quasiperiodic translational order. We found that a bulk topological polarization can be defined for mechanics of quasicrystals that is unique to their non-crystallographic orientational symmetry. References: (1) Di Zhou, Leyou Zhang, Xiaoming Mao, “Topological Edge Floppy Modes in Disordered Fiber Networks”, Phys. Rev. Lett. 120, 068003 (2018); (2) Di Zhou, Leyou Zhang, Xiaoming Mao, “Topological Boundary Floppy Modes in Quasicrystals”, arXiv:1809.09188 (2018).
Computations in Science

May 29, 2019
KPTC 206 | Wednesday, 12:15 pm

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Josh Vura-Weis, Department of Chemistry - UIUC

What Did the Metal Know, and When Did She Know It? Ultrafast XUV Spectroscopy Reveals Short-lived States in Transition Metal Complexes and Organohalide Perovskites

X-ray absorption near edge spectroscopy (XANES or NEXAFS) is a powerful technique for electronic structure determination. However, widespread use of XANES is limited by the need for synchrotron light sources with tunable x-ray energy. Recent developments in extreme ultraviolet (XUV) light sources using the laser-based technique of high-harmonic generation have enabled core-level spectroscopy to be performed on femtosecond to attosecond timescales. We have extended the scope of tabletop XUV spectroscopy and demonstrated that M2,3-edge XANES, corresponding to 3p→3d transitions, can reliably measure the electronic structure of first-row transition metal coordination complexes with femtosecond time resolution. We use this ability to track the excited-state relaxation pathways of photocatalysts and spin crossover complexes. In semiconductors such as CH3NH3PbI3, distinct signals are observed for photoinduced electrons and holes, allowing the dynamics of each carrier to be tracked independently. This work establishes extreme ultraviolet spectroscopy as a useful tool for mainstream research in inorganic, organometallic, and materials chemistry.Host: Andrei Tokmakoff, 4-7696 or via email to tokmakoff@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

May 28, 2019
GCIS W301 | Tuesday, 4:00 pm

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Congjun Wu (UCSD)

Symmetry and Correlation Aspects of Quantum Dynamics

Symmetry and correlation are fundamental aspects of condensed matter physics. A solid state textbook typically starts with crystalline symmetries as classified by space group, and proceeds with the Bloch theorem which sets up the framework of electron’s quantum behavior under crystalline symmetries. We have generalized these concepts to dynamic systems by proposing “dynamic crystal” and updating the Bloch theorem. A new structure of “space-time group” is constructed for describing dynamic symmetries, including the space-time intertwined symmetries of “time-screw-rotation” and “time-glide-reflection”. Dynamic crystal applies to a large class of systems including laser-driven solid state crystals, dynamic photonic crystals and optical lattices. On the other hand, the real frequency responses at high energies is a hardcore problem of strong correlation physics. Our new progress is to employ integrable methods to investigate spin dynamics arising from the Bethe string states, which are exotic many-body excitations of high energy magnon anti-bound states. In particular, the 3-string excitations, i.e., the 3-body anti-bound states, are identified for the first time by comparing the characteristic spectra lines in the electron-spin-resonance spectroscopy measurement on SrCo2V2O8 with the theory calculations.
JFI Special Seminar

May 28, 2019
E223 | Tuesday, 10:00 am

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Teri W. Odom: Northwestern University

Plasmon-molecule Interactions in Confined Volumes


Chemistry

May 24, 2019
Kent 120 | Friday, 1:45 pm

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Elizabeth Simmons, University of California San Diego

Gender Equity , Power Structures, and Implicit Bias in Stem Elizabeth Simmons, University of San Diego

This presentation will start by reviewing data of the current status of gender equity in STEM disciplines and summarizing social science research that illuminates some causes of gender disparities in STEM. With this context established, the focus will shift to how women enter into leadership roles in academic settings, what they experience, and how gender impacts the way they exercise their authority. The final part of the talk will discuss how we can all contribute to changing the face of leadership for the future, to the benefit of all of us in STEM
Physics Colloquium

May 23, 2019
KPTC 106 | Thursday, 3:30 pm

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IME Distinguished Colloquium Series - Sven Rogge

Professor Sven Rogge from the University of New South Wales will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

May 22, 2019
KCBD 1103 | Wednesday, 4:00 pm

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Joshua Shaevitz, Princeton University

Self-driven phase transitions in living matter

The soil dwelling bacterium Myxococcus xanthus is an amazing organism that uses collective motility to hunt in giant packs when near prey and to form beautiful and protective macroscopic structures comprising millions of cells when food is scarce. I will present an overview of how these cells move and how they regulate that motion to produce different phases of collective behavior. Inspired by recent work on active matter and the physics liquid crystals, I will discuss experiments that reveal how these cells generate nematic order, how defect structure can dictate global behavior, and how Myxo actively tune the Péclet number of the population to drive a phase transition from a gas-like flocking state to an aggregated liquid-droplet state during starvation.
Computations in Science

May 22, 2019
KPTC 206 | Wednesday, 12:15 pm

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Gabriela S. Schlau-Cohen, The Department of Chemistry, MIT

Action at the Nanoscale: Single-molecule Studies of Protein Motion

Biological systems exhibit sophisticated responses to environmental and chemical perturbations, often involving conformational motions of their protein building blocks. These motions have been difficult to resolve due to limitations in sensitivity, specificity, and time resolution. We present advances in the analysis of single-molecule data that overcomes these limitations, resolving multiple, microsecond dynamics occurring in parallel within individual proteins. Using single-molecule methods, we explore two processes: (1) photoprotective quenching in oxygenic photosynthesis, gaining a mechanistic understanding of how photosynthetic systems respond to sunny conditions; and (2) the molecular-level motions of the target of cancer drugs, identifying previously hidden connections between the extracellular and intracellular domains of this important protein. Host: Sara Massey, chamberlinsc@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

May 21, 2019
GCIS W301 | Tuesday, 4:00 pm

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Greg Verdine: Harvard University

Pages from the Playbook of Nature


Chemistry

May 20, 2019
Kent 120 | Monday, 3:45 pm

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Alexios Pilychronakos

Generalized Calogero Models and their Hydrodynamics

Calogero-like models and their continuous descriptions appear in various physical systems and have a rich mathematical structure. Some time ago Abanov, Wiegmann and Bettelheim obtained a "dual" formulation of these models that make their soliton excitations manifest. I will use a first-order formulation of Calogero-like models in terms of a generating function to naturally generate their dual form and identify solitons as particles of negative mass. Using this formulation the dual form of Calogero particles in external quartic, trigonometric and hyperbolic potentials is obtained, which were known to be integrable but had no known dual formulation. Their fluid mechanics is also obtained using an intuitive "sawdust" approach. The nontrivial case of elliptic potentials will also be discussed.
Kadanoff Seminar

May 20, 2019
PRC 201 | Monday, 1:30 pm

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Matthew B. Francis, University of California, Berkeley

Versatile Oxidative Coupling Reactions for Site-Selective Protein Modification


Chemistry

May 17, 2019
Kent 120 | Friday, 1:45 pm

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Ania Bleszynski Jayich, University of California Santa Barbara

TBA


Physics Colloquium

May 16, 2019
KPTC 106 | Thursday, 3:30 pm

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Anne McNeil: University of Michigan

Precision Conjugated Polymer Synthesis & Applications


Chemistry

May 16, 2019
GCIS W301 | Thursday, 1:15 pm

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Martin Falk

Simple models for (mostly) biological heterpolymers

Over the past two decades, there have been dramatic developments in our ability to functionalize submicron scale objects with molecules enabling specific interactions between building blocks. However, the range of structures that we can create still pales in comparison to the impressive complexity of structures formed from biopolymers. We would ideally like to understand if there are design principles that can be learned from biology, and adopted in order to design complex structures from simpler heteropolymers. We explore this possibility in the context of chromatin (the term applied to DNA and its associated proteins) and in the context of collagen, and conclude with a discussion of ongoing simulation and experimental work on the folding of 7-particle colloidal clusters.
MRSEC Baglunch

May 16, 2019
GCIS E123 | Thursday, 12:00 pm

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David Lentik, Stanford

Avian Inspired Design

Many organisms fly in order to survive and reproduce. My lab focusses on understanding bird flight to improve flying robots—because birds fly further, longer, and more reliable in complex visual and wind environments. I use this multidisciplinary lens that integrates biomechanics, aerodynamics, and robotics to advance our understanding of the evolution of flight more generally across birds, bats, insects, and autorotating seeds. The development of flying organisms as an individual and their evolution as a species are shaped by the physical interaction between organism and surrounding air. The organism’s architecture is tuned for propelling itself and controlling its motion. Flying animals and plants maximize performance by generating and manipulating vortices. These vortices are created close to the body as it is driven by the action of muscles or gravity, then are ‘shed’ to form a wake (a trackway left behind in the fluid). I study how the organism’s architecture is tuned to utilize these and other aeromechanical principles to compare the function of bird wings to that of bat, insect, and maple seed wings. The experimental approaches range from making robotic models to training birds to fly in a custom-designed wind tunnel as well as in visual flight arena’s—and inventing methods to 3D scan birds and measure the aerodynamic force they generate—nonintrusively—with a novel aerodynamic force platform. The studies reveal that animals and plants have converged upon the same solution for generating high lift: A strong vortex that runs parallel to the leading edge of the wing, which it sucks upward. Why this vortex remains stably attached to flapping animal and spinning plant wings is elucidated and linked to kinematics and wing morphology. While wing morphology is quite rigid in insects and maple seeds, it is extremely fluid in birds. I will show how such ‘wing morphing’ significantly expands the performance envelope of birds during flight, and will dissect the mechanisms that enable birds to morph better than any aircraft can. Finally, I will show how these findings have inspired my students to design new flapping and morphing aerial robots.
Computations in Science

May 15, 2019
KPTC 206 | Wednesday, 12:15 pm

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Dr. Logan Clark & Dr. Rachel G. Farber, James Franck Institute, University of Chicago

Building Quantum Materials Out of Light & Atomic-Scale Growth Mechanism of Niobium Hydrides on Hydrogen Infused Nb(100)

L. Clark - TITLE & ABSTRACT: “Building Quantum Materials Out of Light” -
Can quantum materials be built out of light? Ordinary photons, which freely propagate at the speed of light and don’t interact with each other at all, certainly will not form ordered materials. However, we have used a gas of ultracold atoms in an optical cavity to mediate strong collisions between photons, thus creating conditions suitable to highly ordered states of light. In this system, we have recently observed photon pairs forming topologically-ordered Laughlin states, commencing our exploration into quantum materials made from light. R.G. FARBER TITLE & ABSTRACT: “Atomic-Scale Growth Mechanism of Niobium Hydrides on Hydrogen Infused Nb(100)” -
Niobium (Nb) is the current standard for superconducting radio frequency (SRF) accelerator cavities due to its ultra-low surface resistance (Rs) and high cavity quality factor (Q) at operating temperatures of ~ 2 K. It is known that SRF cavity surface composition and contaminant incorporation is directly related to Q; hydrogen incorporation, which results in the formation of Nb hydrides, has been identified as a major source of decreased Q. There is not, however, a fundamental understanding of the growth mechanism for Nb hydrides. We have investigated Nb(100) samples infused with hydrogen using low-temperature scanning tunneling microscopy (LT-STM) to elucidate the atomic-scale growth mechanism of Nb hydrides. In addition, results from Fermi National Accelerator Laboratory have revealed the beneficial effects of nitrogen doping on SRF cavity performance. To understand the effects of nitrogen doping on Nb hydride growth, ongoing studies are focused on elucidating hydride growth behavior on Nb(100) samples infused with both hydrogen and nitrogen.
JFI Special Joint Postdoc Seminar

May 14, 2019
GCIS W301 | Tuesday, 4:00 pm

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Michael Green: University of California, Irvine

Insights into biological C-H bond activatiion


Chemistry

May 13, 2019
Kent 120 | Monday, 3:45 pm

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Luis Bettencourt, University of Chicago

TBA


Physics Colloquium

May 9, 2019
KPTC 106 | Thursday, 3:30 pm

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IME Distinguished Colloquium Series - Darrell Irvine

Professor Darrell Irvine from Massachusetts Institute of Technology will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

May 8, 2019
KCBD 1103 | Wednesday, 4:00 pm

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Thierry Emonet, Yale University

Conflicts and synergies between individuality and collective behavior

Cells live in communities where they interact with each other and their environment. By coordinating individuals, such interactions often result in collective behavior that emerge on scales larger than the individuals that are beneficial to the population. At the same time, populations of individuals, even isogenic ones, display phenotypic heterogeneity, which diversifies individual behavior and enhances the resilience of the population in unexpected situations. This raises a dilemma: although individuality provides advantages, it also tends to reduce coordination. I will report on our recent experimental and theoretical efforts that use bacterial chemotaxis as model system to understand, the origin of individual cellular behavior and performance, and how populations of cells reconciliate individuality with group behavior.
Computations in Science

May 8, 2019
KPTC 206 | Wednesday, 12:15 pm

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Zohar Komargodski, Weizmann

Dynamics of Quantum Field Theory in 2+1 Dimensions with Chern-Simons Interactions


Kadanoff Seminar

May 7, 2019
PRC 201 | Tuesday, 2:00 pm

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Bruce Berne, Columbia University

Molecular Dynamics: a Personal Retrospective


Rice-Berry Lecture

May 6, 2019
Kent 120 | Monday, 3:45 pm

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Cristiano Ciuti, Université de Paris, MPQ, CNRS, France

Quantum Cavities: From Vacuum Manipulation to Photon Simulation of Quantum Materials

In this talk, I will discuss two emerging frontier topics concerning quantum optical cavities. In the first part, I will show how the vacuum field of an electromagnetic resonator can dramatically control the dc magnetotransport of a 2D electron gas without illumination [1,2]. In the second part, I will present recent theoretical results via the corner-space renormalization [3] in finite-size systems revealing how 1D and 2D lattices of quadratically-driven electromagnetic resonators can simulate magnetic phase transitions in the quantum critical regime [4].
JFI Special Seminar

May 6, 2019
KPTC 206 | Monday, 2:00 pm

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Gregory Fu, CALTECH

Photoinduced, Copper-Catalyzed Substitution Reactions of Alkyl Electrophiles


Kharasch Lecture

May 3, 2019
Kent 120 | Friday, 1:45 pm

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Malleable matter: Designing disordered metamaterials by natural aging

Bring good cheer and merriment: 12:00
Bring brains : 12:15
MRSEC Baglunch

May 3, 2019
GCIS E123 | Friday, 12:00 pm

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FORUM 2019

Facilities Open-house Research Users Meeting

FORUM 2019
Facilities Open-house Research Users Meeting

Are innovation and resourcefulness part of your company's mission and philosophy?

Please join us for our first UChicago FORUM event focused on getting to know students, public access instrumentation facilities, and other regional resources.

What is the FORUM?

The FORUM is one of several ways for industry to see how resources, research, and talent at the University of Chicago aligns with their innovation needs.

Many companies are unaware of the opportunities available on campus. These opportunities include a variety of ways to get your foot in the door to test the waters. These opportunities include

Senior design projects in materials chemistry and engineering,
Advanced instrumentation and training available at hourly rates,
Project and internship based talent recruitment, as well as
Discovery of how faculty research topics are aligned with your innovation efforts.
Other avenues include networking with translational technology experts at the Polsky Center for Innovation and Entrepreneurship and other groups on or associated with the campus.

Register Now!

Who is this meeting for?

Corporate decision makers, Industrial/corporate scientists and engineers involved with:

Innovation Design & Implementation
Chemical Engineering
Process Development
Materials Science & Engineering
Failure Analysis
Materials Characterization
Also - Targeted talent recruitment of undergraduates and graduate students through internships, senior design projects, and consulting opportunities.
Tentative itinerary -

8:15 - 9:00 am Registration / Breakfast & Coffee
9:00 - 9:15 am Opening Remarks
9:15 - 10:30 am Project snapshots

10:30 - 11:00 am BREAK
11:00 - 11:45 am Keynote talk - Dr. Maria Kokkori (The Art Institute of Chicago)

11:45 - 1:00 pm Networking LUNCH
1:00 - 2:00 pm Poster session

2:00 - 3:00 pm Breakout sessions
3:00 - 4:00 pm. Facility Tours (limited space! - Sign up early)
MRSEC Special Event

May 3, 2019
ERC 161 | Friday, 8:15 am

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Phil Morrison, University of Texas, Austin

Joint CAM Colloquium

Physical models that describe the dynamics of matter, whether they be discrete, like those for interacting particles or dust, or continuum models, like those for fluids and plasmas, possess structure. Structure may manifest by sets of conservation laws resulting from Galilean or Poincare invariance, or by the property of entropy production giving relaxation to thermal equilibrium. Ultimately, structure arises from an underlying Hamiltonian form that may or may not be maintained in approximations and/or reductions of various kinds.

I will survey the Hamiltonian structure possessed by a variety of models, with an emphasis on a general magnetofluid model and Vlasov-Maxwell theory. In addition I will discuss structure preservation in numerical implementation. Although symplectic integration has been well studied and widely used for _x000C_finite-dimensional systems, the preservation of the structure that occurs in continuum models such as extended magnetohydrodynamics with generalized helicities, is considerably more difficult to implement. Progress in developing a discrete version of the Maxwell-Vlasov system that preserves its Hamiltonian structure, and its numerical implementation will be discussed.
Computations in Science

May 2, 2019
Eckart Hall 202 | Thursday, 4:00 pm

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Kawtar Hafidi, Argonne National Laboratory

Next Generation Nuclear Experiments: Toward 3D Imaging of Nuclei Kawtar Hafidi, Argonne National Laboratory

Inclusive deep inelastic scattering experiments have been instrumental in advancing our understanding of the Quantum Chromodynamics (QCD) structure of nuclei and the effect of nuclear matter on the structure of bound hadrons. A great example is the observation by the European Muon Collaboration (EMC) of a deviation of the deep inelastic structure function of a nucleus from the sum of the structure functions of the free nucleons, the so-called EMC effect. On the theory side, despite decades of theoretical efforts with increased sophistication, a unifying physical picture of the origin of the EMC effect is still a matter of intense debate. To reach the next level of our understanding of nuclear QCD and unravel the partonic structure of nuclei, experiments need to go beyond the inclusive measurements and focus on exclusive and semi-inclusive reactions. In this talk, results of the first exclusive measurement of deeply virtual Compton scattering off He-4 will be presented. Future measurements at Jefferson Lab 12 GeV using a new Low Energy Recoil Tracker will be discussed. We will conclude by introducing the importance of an Electron Ion Collider with high polarized luminosity and variable energy with comprehensive recoil detection in probing the gluonic and sea quark landscape of nuclei.
Physics Colloquium

May 2, 2019
KPTC 106 | Thursday, 3:30 pm

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Rafael Jaramillo, The Department of Materials Science, MIT

Mechanism and New Applications of Large and Persistent Photoconductivity

ABSTRACT: Abstract: Large and persistent photoconductivity (LPPC) in semiconductors is due to the trapping of photo-generated minority carriers at crystal defects. Theory suggests that anion vacancies in II-VI semiconductors are responsible for LPPC due to negative-U behavior, whereby two minority carriers become kinetically trapped by lattice relaxation following photo-excitation [1-2]. By performing a detailed analysis of photoconductivity in CdS, we provide experimental support for this negative-U model of LPPC [3]. We also show that LPPC is correlated with sulfur deficiency. We use this understanding to vary the photoconductivity of CdS films over nine orders of magnitude, and vary the LPPC characteristic decay time from seconds to 10,000 seconds, by controlling the activities of Cd2+ and S2- ions during chemical bath deposition. We suggest a screening method to identify other materials with long-lived, non-equilibrium, photo-excited states based on the results of ground-state calculations of atomic rearrangements following defect redox reactions, with a conceptual connection to polarons and organic dyes.

We apply our knowledge of defect physics in CdS to propose and design a new type of semiconductor device – the donor level switch (DLS), which operates by switching individual defects between deep-donor and shallow-donor states. We study DLS behavior by making two-terminal devices using hole injection layers to control the charge state of sulfur vacancies. We also apply our knowledge to study the influence of LPPC on the performance of CIGS thin-film solar cells.

If time allows we will also cover recent results from our group on infrared optical properties and phase-change functionality in transition metal di-chalcogenides (TMDs), and early results on growth and the opto-electronic performance of sulfide perovskite semiconductors.
[1] S. B. Zhang, S.-H. Wei & A. Zunger, Phys. Rev. B 63, 075205 (2001).
[2] S. Lany & A. Zuner, Phys. Rev. B 72, 035215 (2005).
[3] H. Yin, A. Akey & R. Jaramillo, Phys. Rev. Mater. 2, 084602 (2018).
Joint JFI & IME Seminar

May 2, 2019
GCIS 500A | Thursday, 2:00 pm

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Barry Bradlyn, Urbana

Viscoelastic response of quantum Hall states

One hallmark of topological phases with broken time reversal symmetry is the appearance of quantized non-dissipative transport coefficients, the archetypical example being the quantized Hall conductivity in quantum Hall states. Here I will talk about a new non-dissipative transport coefficients that appear in such systems - the Hall viscosity. In the first part of the talk, I will start by reviewing previous results concerning the Hall viscosity, including its relation to a topological invariant known as the shift when rotational symmetry is preserved. Next, I will show how the Hall viscosity can be computed from a Kubo formula, and the experimental implications this insight yields. In the second part of the talk, I will examine the fate of the Hall viscosity when rotational symmetry is broken. Through a combination of field theory and numerical techniques, I will show that rotational symmetry breaking allows for the introduction of a new topological quantum number characterizing quantum Hall states. I will present results on the stress response of quantum Hall systems in a tilted magnetic field. In addition to the Hall viscosity, I will show that the stress tensor acquires an unusual anisotropic ground state average, leading to anomalous elastic response functions.
Kadanoff Seminar

May 1, 2019
PRC 201 | Wednesday, 1:30 pm

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Pankaj Mehta, Boston University

Toward a Statistical Mechanics of Microbiomes

A major unresolved question in microbiome research is whether the complex ecological patterns observed in surveys of natural communities can be explained and predicted by fundamental, quantitative principles. Bridging theory and experiment is hampered by the multiplicity of ecological processes that simultaneously affect community assembly and a lack of theoretical tools for modeling diverse ecosystems. In the first part of the talk, I will present a simple ecological model of microbial communities that reproduces large-scale ecological patterns observed across multiple experimental settings including compositional gradients, clustering by environment, diversity/harshness correlations, and nestedness. Surprisingly, our model works despite having a “random metabolisms” and “random consumer preferences”. This raises the natural of question of why random ecosystems can describe real-world experimental data. In the second, more theoretical part of the talk, I will answer this question by showing that when a community becomes diverse enough, it will always self-organize into a stable state whose properties are well captured by a “typical random ecosystems”. If time permits, I will also highlight surprising connections between ecological dynamics, constrained optimization, and kernel-based machine learning methods such as Support Vector Machines.

Talk is based on: Advani et al J. Stat. Phys (2018); Golford et al Science (2018); Marsland et al. PLoS Comp Bio (2019); arXiv:1809.04221;arXiv:1901.09673; arXiv:1904.02610; unpublished
Computations in Science

May 1, 2019
KPTC 206 | Wednesday, 12:15 pm

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Gregory Fu, CALTECH

Nickel-Catalyzed Substitution Reactions of Alkyl Electrophiles


Kharasch Lecture

May 1, 2019
GCIS W301 | Wednesday, 12:00 pm

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Jay Foley, The Department of Chemistry, William Patterson University

Jay Foley, The Department of Chemistry, William Patterson University

The interaction between light and nanostructures can give rise to a number of different resonant phenomena, including plasmon resonances in metal nanoparticles, excitonic resonances in semiconductor nanoparticles, and scattering resonances in dielectric nanoparticles. An exciting feature of these resonant phenomena is that they provide opportunities to control the flow of optical energy at the nanoscale, a prospect which has important implications for renewable energy technologies among others. Creating hybrids of various nanoscale materials can often lead to new emergent phenomena, giving us yet more levers of control over light at the nanoscale. I will discuss two classes of hybrid nanostructures that give rise to emergent phenomena that show promise for energy conversion applications. The first class of hybrids includes multilayer planar nanomaterials whose emergent properties allow us to control how they radiate heat. The second class of hybrids consists of dielectric and metal nanospheres whose emergent properties offer new routes for light initiated energy transfer, including hot-carrier transfer and resonance energy transfer, to small molecules. I will describe ongoing efforts to develop simple but accurate theoretical and computational techniques to study and design these systems. Host: David Mazziotti, 4-1762 or via email at damazz@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

April 30, 2019
GCIS W301 | Tuesday, 4:00 pm

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Kharasch Lecture: Professor Gregory Fu, Caltech

Nucleophilic Substitution Reactions: A Radical Alternative to Sn1 and Sn2 Reactions

Classical methods for achieving nucleophilic substitutions of alkyl electrophiles (SN1 and SN2) have limited scope and are not generally amenable to enantioselective variants that employ readily available racemic electrophiles. In this presentation, we will describe how the combination of radical chemistry and transition-metal catalysis has opened the door to addressing the challenges of reactivity and of enantioselectivity in nucleophilic substitution reactions of secondary and tertiary alkyl electrophiles.
Chemistry

April 29, 2019
Kent 120 | Monday, 3:45 pm

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Kristan Jensen, San Francisco State University

de Sitter, SYK, and coadoint orbits


Kadanoff Seminar

April 29, 2019
PRC 201 | Monday, 1:30 pm

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Philippe Bourrianne, Mechanical Engineering, MIT, Cambridge, MA, USA

Colloids and liquids from suspensions to superhydrophobicity

Colloidal suspensions are ubiquitous in our daily life. Micrometric particles dispersed in a solvent are indeed present in common liquids such as paints, inks or even food products. We will discuss the properties of those colloidal suspensions from their liquid phase to solid deposits after drying.
First, colloidal suspensions exhibit a wide range of rheological behaviors from shear-thinning to yield stress fluids. We will focus on the shear-thickening transition when dense suspensions experience a dramatic increase in viscosity above a critical shear-stress. By changing the physico-chemistry of the particles, we can tune this rheological transition and thus understand the interactions involved in this behavior.
Increasing concentration can also be noticed during drying when solvent evaporates: particles finally form a solid deposit. After drying, a drop of a colloidal suspension leads to a variety of patterns from coffee-stain to more homogeneous coatings in paintings. We will discuss the effect of the initial concentration of particles on the drying pattern and on the subsequent mechanical instabilities.
Finally, after the whole drying of the colloidal suspension, coatings are achieved. Depending of the nature of the particles, we can tune the wettability of the substrate up to superhydrophobic solid. We will briefly discuss how such a water-repellent substrate can allow levitation of liquids.

We are grateful to host Thomas Videbaek for arranging this visit.
MRSEC Baglunch

April 26, 2019
GCIS E223 | Friday, 3:00 pm

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Professor Yan Xia: Stanford University

Building and Breaking Strained Molecular Ladders to Develop Antiaromatic and Force-Responsive Materials


Chemistry

April 26, 2019
Kent 120 | Friday, 1:45 pm

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Herbert Mayr, Ludwig-Maximilians-Universität München

Mythology in Organic Chemistry: How Obsolete Concepts Survive


Chemistry

April 25, 2019
Kent 102 | Thursday, 4:00 pm

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Ritchie Patterson, Cornell University

Mastering Bright Electron Beams

Bright electron beams enable electron microscopy, brilliant X-ray sources, and collisions that probe the interactions of elementary particles. They are also essential for semiconductor device fabrication, the sterilization of medical equipment and the production of heat shrink tubing and tires. Achieving increased brightness and extending the scientific and industrial reach of these beams poses basic scientific questions about beam production, acceleration and transport, whose answers will require expertise spanning disciplines from ab initio physics, materials science, surface chemistry, and mathematics to accelerator physics. A new NSF Science and Technology Center, the Center for Bright Beams, has been formed to do exactly this. The colloquium will present some of the key scientific questions involved in producing and using future bright beams and Center for Bright Beams early results.
Physics Colloquium

April 25, 2019
KPTC 106 | Thursday, 3:30 pm

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Andrew Houck, The Department of Electrical Engineering, Princeton University

Many-body Quantum Optics in Superconducting Circuits

Superconducting circuits provide an excellent platform for the study of non-equilibrium quantum simulation and quantum simulation in exotic lattices. In circuit QED, a superconducting qubit mediates very strong effective photon-photon interactions. In networks of circuit QED elements, a competition between hopping and interactions can be realized, leading to steady state phase transitions in a damped driven system. Here, we will discuss dynamical phase transitions in a circuit QED dimer and dissipative phase transitions observed in a one-dimensional lattice, tunable interactions in a bandgap medium, and progress towards understanding lattices in curved space.Host: Jonathan Simon, 2-9661 or via email at simonjon@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI Special Seminar

April 25, 2019
KPTC 206 | Thursday, 12:00 pm

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IME Distinguished Colloquium Series - Jeffrey Moore

Professor Jeffrey Moore from University of Illinois will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

April 24, 2019
KCBD 1103 | Wednesday, 4:00 pm

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Naomi Ginsburg, The Department of Physics, University of California-Berkeley

How Do Emerging Light Harvesting Materials Form, Transform, and Transport Energy at the Nanoscale?

We are interested in the optoelectronic properties and the spatiotemporal nature of photogenerated energy carrier transport of emerging semiconducting materials, broadly defined. These materials include not only semiconductors who basic building blocks are atoms but also those made of small particles or molecules, including the aggregates of molecular pigments involved in photosynthesis. Those of greatest interest to us are ones that spontaneously assemble into organized and/or densely packed solid structures starting from the solution phase or whose structures can be thermodynamically or kinetically transformed. What are the multiscale relationships between the dynamics and products of material formation and transformation and the emergent electronic properties of these materials? How does disorder, as an inherent byproduct of the assembly process, affect these properties both locally and macroscopically?

To answer these questions I will provide examples of our work to elucidate the mechanisms for ultrafast photoinduced energy transport and for the slower dynamics of material transformations in a wide range of emerging, heterogeneous electronic materials. This work has often required the development of spectroscopic nano-imaging modalities with new, more appropriate combinations of spatial sensitivity and temporal resolution. As examples, I will take you first on a journey with transient optical elastic scattering to reveal the nature of energy flow–structure correlations for various photogenerated species in virtually any semiconductor. In related materials, we will then explore the nature of structural phase transitions both at and away from equilibrium using cathodoluminescence microscopy – the mapping of light emitted from a sample in a scanning electron microscopy – and in situ X-ray scattering.
Host: Sara Sohail,2-6066 or via email at skhess@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
Closs Lecture

April 24, 2019
GCIS W301 | Wednesday, 2:15 pm

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Risi Kondor, University of Chicago

Covariant neural network architectures for learning physics

Deep neural networks have proved to be extremely effective in image recognition, machine translation, and a variety of other data centered engineering tasks. However, generalizing neural networks to learning physical systems requires a careful examination of how they reflect symmetries. In this talk we give an overview of recent developments in the field of covariant/equivariant neural networks. Specifically, we focus on three applications: learning properties of chemical compounds from their molecular structure, image recognition on the sphere, and learning force fields for molecular dynamics. The work presented in this talk was done in collaboration with Brandon Anderson, Zhen Lin, Truong Son Hy, Horace Pan, and Shubhendu Trivedi.
Computations in Science

April 24, 2019
KPTC 206 | Wednesday, 12:15 pm

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Joseph Mindell, MD-PhD, NINDS-NIH

Protons to Patients: Evaluating the role of the chloride transporter ClC-7 in lysosomal function

Lysosomes are essential focal points of cellular metabolism, digesting a wide range of macromolecules provided by endocytosis or autophagy. To this end, lysosomes rely on their highly acidic luminal pH to promote the function of their many enzymes, a pH generated by the action of a v-Type proton pumping ATPase. Since this transporter is electrogenic, parallel ion movements must occur to dissipate the generated membrane potential and promote bulk proton flux. The Cl-/H+ antiporter, ClC-7, has been proposed to play this role, moving Cl- in parallel to protons. However, the function of ClC-7 has been controversial, with conflicting reports on its contribution to lysosomal acidification. I will discuss recent work aimed at understanding the role of ClC-7 and other proteins in the acidification process. My lab uses a multipronged approach, utilizing a variety of methods to probe these processes, from flux studies in isolated organelles to knockout mice and quantitative imaging methods. In addition I will report on two patients with a novel disease manifested as widespread lysosomal dysfunction but no bone abnormalities, who both have the same missense mutation in ClC-7. Acidification defects in cells from these patients, along with electrical currents from the mutant transporter provide novel insight into ClC-7 function. These findings provide strong support for an important role of ClC-7 in the lysosomal acidification process and suggest opportunities for therapies for these patients.
Biophysical Dynamics

April 23, 2019
GCIS W301 | Tuesday, 12:00 pm

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Yogi Surendranath: MIT

Bridging Molecular and Heterogeneous Electrocatalysis Through Graphite Conjugation


Chemistry

April 22, 2019
Kent 120 | Monday, 1:45 pm

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Jon Sorce, Stanford University

Tensor Networks and Emergent Spacetime in AdS/CFT

One of the most remarkable insights gleaned from studying the AdS/CFT correspondence is that information about the structure of spacetime can be recovered by studying entanglement in the underlying quantum-gravitational degrees of freedom. As such, there is good evidence to believe that understanding entanglement in quantum systems is essential to understanding the emergence of spacetime in quantum gravity. In this talk, I will present recent on work in which general principles from quantum information theory are used to distill emergent geometric structures—so-called “tensor networks”—from arbitrary states in quantum field theory. When these states are chosen from conformal field theories in the AdS/CFT correspondence, the tensor network geometry matches the spacetime geometry of the AdS bulk.
Organizer: Kadanoff Center seminars
Kadanoff Seminar

April 22, 2019
PRC 201 | Monday, 1:30 pm

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Mechanical duality

Discussion over lunch: 12:00
Discussion over duality: 12:15
MRSEC Baglunch

April 19, 2019
GCIS E123 | Friday, 12:00 pm

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AbbVie Visit Day

Hosted by Chemistry and My CHOICE

To register for lunch, afternoon seminars and Q&A session please go to https://abbvieday2019.eventbrite.com

9:30am Jay Cui (Associate Director, AbbVie Ventures) "Landscape in Early Investments in Life Sciences"
RESERVATION REQUIRED: Contact Prof. Dickinson dickinson@uchicago.edu
12:00pm Lunch with Trainees ~ Limited seats available. Registration required.
1:15pm SEMINARS:
Amanda Dombrowksi (Sr. Scientist II) "Enabling and Accelerating Drug Discovery with Chemistry Technologies"
Aleks Baranczak (Sr. Scientist) "Mechanistic Characterization at the Molecular Level: Chemical Biology in Drug Discovery"
Chemistry

April 19, 2019
Kent 120 | Friday, 9:30 am

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Rob Phillips, California Institute of Technology

How Schrodinger's Cat Became a Cat


Physics Colloquium

April 18, 2019
KPTC 106 | Thursday, 3:30 pm

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Detlef Lohse, University of Twente

Evaporation of multicomponent droplets

While the evaporation of a single component droplet meanwhile is pretty well understood, the richness of phenomena in multicomponent droplet evaporation keeps surprising us. In this talk we will show and explain several of such phenomena, namely evaporation-triggered segregation thanks to either weak solutal Marangoni flow or thanks to gravitational effects, and the evaporation of ternary liquid droplet, which can lead to spontaneous nucleation of droplets consisting of a new phase. We will also show how this new phase can be utilized to self-lubricate the droplet in order to suppress the coffee stain effects. The research work shown in this talk combines experiments, numerical simulations, and theory.
Computations in Science

April 18, 2019
GCIS E223 | Thursday, 2:00 pm

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Johanna Knapp, University of Vienna

GLSMs, CYs, and Localization

Gauged linear sigma models (GLSMs) can be used to study Calabi-Yaus and their moduli spaces. Recent results in supersymmetric localization have made it possible to compute exact, i.e. fully quantum corrected, quantities that are relevant in string compactifications directly in the GLSM. After a review of the general framework, I will present some recent applications, with focus on the sphere and hemisphere partition function of the GLSM.
Theory Seminar

April 17, 2019
PRC 201 | Wednesday, 1:30 pm

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Nikta Fakhri, MIT

Thermodynamics of active matter

Cellular structures constantly consume and dissipate energy on a variety of spatiotemporal scales in order to function. While progress has been made in elucidating their organizing principles, much of their thermodynamics remains unknown. In this talk, I will address the question: why measure dissipation in such nonequilibrium systems? I will show that by measuring a multi-scale irreversibility (time-reversal asymmetry) one can extract model-independent estimates of the time-scales of energy dissipation based on time series data collected in an experimental biological system. I further demonstrate that the irreversibility measure maintains a monotonic relationship with the underlying biological nonequilibrium activity. The basic idea of estimating irreversibility for various levels of coarse-graining is quite general; we expect it to lead to important inferences whenever there is a well-defined notion of dissipative scale.
Computations in Science

April 17, 2019
KPTC 206 | Wednesday, 12:15 pm

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Lulu Qian, The Department of Bioengineering, Caltech

Algorithmic and Architectural Foundations for Programmable Molecular Machines: DNA Robots, Information-processing Circuits, and Reconfigurable Nanostructures

The primary focus of my lab is to help establish the algorithmic and architectural foundations for artificial molecular machines, through rationally designed and synthesized nucleic-acid systems that exhibit programmable behaviors. We aim to better understand how complex network behaviors arise from simple molecular building blocks, to establish forward engineering principles for information processing with molecules, to precisely manipulate matter at the nanoscale and embed control within biochemical environments, and eventually, to create artificial molecular machines that approach the complexity and sophistication of the natural ones and are fully programmable by humans.

In this talk, I will discuss our recent contributions in three areas: molecular robots, information-processing circuits, and reconfigurable DNA nanostructures.

First, we developed molecular robots that autonomously and collectively perform a sophisticated mechanical task: exploring the surface of a DNA nanostructure, picking up multiple types of cargo molecules and sorting each type to a designated location (Thubagere et al., Science, 2017). This work exploits random walks for energy-efficient mechanical behaviors, demonstrates the importance of simple algorithms and modular building blocks, and provokes further development of general-purpose molecular robotics.

Second, we created biochemical circuits that can classify highly complex and noisy molecular information, based on the similarity to a set of memories stored in DNA-based artificial neural networks (Cherry et al., Nature, 2018). This work shows how competition between molecules can be used to process complex information, establishes the record for how much intelligence can be built into artificial molecular machines, and paves the way for programming molecules to learn from their environment.

Finally, we invented a hierarchical and recursive strategy that allows DNA nanostructures with increasing sizes and arbitrary patterns to be created using a small and constant set of unique DNA strands (Tikhomirov et al., Nature, 2017). Subsequently, we discovered a simple yet powerful mechanism that controls the dynamic interactions between complex DNA nanostructures. Utilizing this mechanism, we demonstrated information-based autonomous reconfiguration in systems of interacting DNA nanostructures (Petersen et al., Nature Communications, 2018). Together, the two approaches provide significantly advanced structural components for building artificial molecular machines.

I hope to illuminate an ever-more-promising future for molecular sciences, empowered by the advances in DNA nanotechnology and molecular programming – a field that has its roots in physics, computer science, and engineering, and is anticipated to revolutionize the methods in many othe
The Tuesday JFI Seminar

April 16, 2019
GCIS W301 | Tuesday, 4:00 pm

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Eric Klein, PhD, Rutgers University-Camden

Adaptation to phosphate-limitation in Caulobacter crescentus

Bacteria are constantly encountering new environmental conditions that require a variety of adaptations including metabolism, gene expression, and cellular morphology. In our model organism, Caulobacter crescentus, adaptation to phosphate limitation includes the dramatic elongation of its polar stalk appendage. Recent work from our lab has shown that stalk elongation and adaptation to phosphate starvation involves changes in membrane composition, peptidoglycan organization, and sugar metabolism. Importantly, our findings have implications for other bacterial species related to pathogenesis and cell growth.
Biophysical Dynamics

April 16, 2019
GCIS W301 | Tuesday, 12:00 pm

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Thomas Muir: Princeton University

Painting Chromatin with Synthetic Protien Chemistry


Chemistry

April 15, 2019
Kent 120 | Monday, 3:45 pm

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Emil Yuzbashyan, Rutgers University

Integrable time-dependent Hamiltonians

In the emerging field of coherent many-body dynamics, we seek to understand the behavior of an isolated quantum many-body system driven far from equilibrium by changing its Hamiltonian in time. In this talk, I will identify a general class of many-body and matrix Hamiltonians for which this problem is exactly solvable. In particular, I will outline a way to make the parameters (e.g., the interaction strength) of certain quantum integrable models time-dependent without breaking their integrability.

Interesting many-body models that emerge from this approach include a superconductor with the interaction strength inversely proportional to time, a Floquet BCS superconductor, and the problem of molecular production in an atomic Fermi gas swept through a Feshbach resonance as well as various models of multi-level Landau-Zener tunneling. I will solve the non-stationary Schrodinger equation exactly for all these models and discuss some interesting physics that emerges at large times.
Kadanoff Seminar

April 15, 2019
PRC 201 | Monday, 1:30 pm

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The heart of crumpling

or how to (in)crease your core

Bring your food to eat at 12:00
Bring a tidbit to tell

The story begins at 12:15
MRSEC Baglunch

April 12, 2019
GCIS E123 | Friday, 12:00 pm

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William Unruh, University of British Columbia

Experimental Measurement of the Hawking emission (?)

Hawking's discovery 45 years ago that black holes, instead of ever growing sinks of energy, emitted radiation and very slowly shrank in size and mass, was one of the most surprising discoveries of physics in the 20th century. Of course physics in an experimental or at least observational science. But small enough black holes to see this effect are rare.

However analogies exist in which one could hope to see this effect, namely flowing fluids where the velocity of flow exceeds the velocity of sound. While
the classical correlate of this has been measured for surface waves in water, recently the quantum effect has also been measured for sound waves in a BEC. I will review the Hawking effect, the measurement in water and these new measurements where one can claim to have seen at least some of the quantum effects of the Hawking process.
Physics Colloquium

April 11, 2019
KPTC 106 | Thursday, 3:30 pm

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Bernhard Breit, Albert-Ludwigs - University Freiburg

Rhodium-Catalyzed Addition of Pronucleophiles to Alkynes and Allenes: An Atom-Efficient Alternative to the Tsuji-Trost Reaction


Special Organic Syntheses Lecture

April 11, 2019
GCIS W301 | Thursday, 2:00 pm

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IME Distinguished Colloquium Series - Rohit Karnik

Professor Rohit Karnik from Massachusetts Institute of Technology will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

April 10, 2019
KCBD 1103 | Wednesday, 4:00 pm

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Oskar Hallatschek, UC Berkeley

The role of jackpot events in the dynamics of evolution

Luria and Delbrück discovered that mutations that occur early during a growth process lead to exceptionally large mutant clones. These mutational “jackpot” events are thought to dominate the genetic diversity of growing cellular populations, including biofilms, solid tumors and developing embryos. In my talk I show that jackpot events can be generated not only when mutations arise early but also when they occur at favourable locations, which exacerbates their role in adaptation and disease. I will also consider the impact of recurrent jackpot events, which lead to a bias favoring alleles that happen to be present in the majority of the population. I argue that this peculiar rich-get-richer phenomenon is a general feature of evolution driven by rare events.
Computations in Science

April 10, 2019
KPTC 206 | Wednesday, 12:15 pm

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Zeger Hens, The Department of Inorganic & Physical Chemistry, Ghent University

Stimulated Emission by Colloidal Quantum Dots

Reducing the size of materials down to a few nanometer is a powerful approach to control material properties by design. A case in point are semiconductors, where size quantization leads to a size- and shape-dependent band gap once crystal dimensions become comparable or smaller than the exciton Bohr radius; an observation first made almost 40 years ago.
This talk explores the opportunities size reduction brings for creating new optical gain materials. Using free carrier gain in bulk semiconductors as a reference, we discuss 4 different model systems, each exemplifying a different mechanism to attain net stimulated emission.
First, we focus on large perovskite nanocrystals. This example helps introducing the experimental methods we use to characterize gain materials and shows that weakly confined semiconductors have gain characteristics highly similar to the corresponding bulk material. Next, we highlight the impact of size quantization using stimulated emission by CdSe/CdS quantum dots as a second example, which is introduced as a unique model system of band-edge gain by quantum dots. Interestingly, we show that tweaking the core and shell dimensions provides unique possibilities to tune the optical gain characteristics of these materials.
Building on the conditions that yield the lowest gain thresholds in CdSe/CdS quantum dots, we discuss two possibilities to overcome intrinsic limitations of band-edge gain. First, we turn to two-dimensional colloidal nanoplatelets, were we show that stimulated emission through excitonic molecules leads to a combination of low gain thresholds and high gain coefficients. Finally, we propose transitions involving localized band-gap states, exemplified by HgTe quantum dots, as a way to achieve nearly thresholdless gain by colloidal semiconductor nanocrystals. We conclude this presentation by a short outlook on the prospects and challenges on using colloidal quantum dots as a gain material for microlasers. Host(s): Philippe Guyot-Sionnest, 2-7461; Email-pgs@uchicago.edu & Dmitri Talapin, 4-2607; Email - dvtalapin@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or via email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

April 9, 2019
GCIS W301 | Tuesday, 4:00 pm

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Monika Scholz, PhD, Princeton

Reading the mind of the worm: Brain-wide neural dynamics predict behavior in C. elegans

How does a nervous system control animal behavior? While models of behavior and neural computation exist, investigating the connection experimentally is challenging in even the simplest organisms. It is only recently that tools have become available to image the behavior and neural dynamics simultaneously in the roundworm C. elegans. Its small nervous system with only 302 neurons and stereotyped behaviors allow us to probe how well simple models perform in predicting behavior from neural dynamics alone. We use a suite of microscopy tools and a calcium-sensitive fluorescent protein to image the activity of a large number of neurons in the animals brain during locomotion. Using a linear model, we predict forward and backward velocity as well as turns and turn direction from neural activity. Using our model and the animals neural activity, we can predict the worms posture for up to 10 seconds. I will discuss the implications for understanding how neural networks encode information and how this information could be used in coordinating complex motor tasks.
Biophysical Dynamics

April 9, 2019
GCIS W301 | Tuesday, 12:00 pm

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Richa Batra, Creative Machines Lab, Columbia University

Particle Robotics: Statistical Mechanics of Loosely Coupled Robotic Components

Traditional robots typically consist of highly-engineered modules, each performing specialized roles to complete
complex tasks. While these robots are accomplishing functions of increasing complexity with greater precision,
they frequently struggle when presented with novel environments, or the failure of a single component. This talk
will explore robotic systems inspired by biology and nature, in which adaptable and resilient behaviors are
achieved by combining and coordinating relatively simple components. Like atoms forming crystals, cells
contracting muscle tissue, or ants foraging for food, complexity can arise from relatively simpleparts.
The robotic system presented, called particle robotics, exploit statistical mechanics of loosely coupled components. This
talk will mainly focus on a particle robot where each component, or particle, is only capable of uniform volumetric oscillations.
The oscillations of the individual particles can be phase-modulated by a global signal. Despite the amorphous
configurations and lack of direct control, we find that we are able to coordinate the overall behavior of the robot. We
demonstrate the scalability and resilience of such robots, both to noisy components and to component failure. In addition,
particle robots comprising components that exhibit different individual behaviors will be presented. The particle robotics
paradigm presented here suggests that large-scale, amorphous robotic systems can exhibit deterministic behavior even
when composed of simple stochastic component.
Special JFI Seminar

April 9, 2019
GCIS E123 | Tuesday, 11:30 am

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Floyd Romesberg, The Scripps Research Institute

A Semi-Synthetic Organism that Stores and Retrieves Increased Genetic Information


Closs Lecture

April 8, 2019
Kent 120 | Monday, 4:00 pm

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Zhihao Zhuang, University of Delaware

Chemical Approaches for Investigating Protein Deubiquitination

The human ubiquitin proteasome system is involved in many cellular processes, including protein quality control, epigenetic regulation, DNA damage repair and tolerance. Many cellular events are regulated through reversible protein ubiquitination. Deubiquitinases (DUBs) as an important class of enzymes in the ubiquitin proteasome system have been associated with various human diseases including cancer, neurological disorders, and viral infection. DUBs are emerging as promising targets for pharmacological intervention and major efforts targeting DUBs for drug discovery are underway. I will discuss the development of a series of novel DUB probes for elucidating the ubiquitin chain linkage and target protein specificity of DUBs. We also developed cell-permeable DUB probes that allow profiling of DUB activities in intact cells. Using the newly developed probes and chemical proteomics approaches, exciting new findings on the DUB specificity and catalysis were obtained. Our efforts led to much needed tools and approaches for understanding the complex biology of protein ubiquitination and will drive the drug discovery efforts targeting the many DUBs in humans.
Chemistry

April 5, 2019
Kent 120 | Friday, 1:45 pm

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Luca Grandi, University of Chicago

TBA


Physics Colloquium

April 4, 2019
KPTC 106 | Thursday, 3:30 pm

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Christof Sparr, University of Basel

Cataltic Cascade Reactions Inspired by Polyketide Biosynthesis


Special Organic Syntheses Lecture

April 4, 2019
GCIS W301 | Thursday, 1:30 pm

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Semyon Klevtsov, University of Cologne

Geometric responses of Quantum Hall states

One way to understand the Quantum Hall effect is to consider QH wave functions on Riemann surfaces. Electromagnetic and gravitational responses correspond to varying metric and magnetic field and
quantized coefficients are encoded in Chern classes on associated parameter (moduli) spaces. We report on our recent work and discuss various questions arising in this approach.
Kadanoff Seminar

April 3, 2019
PRC 201 | Wednesday, 3:00 pm

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Greg Bewley, Cornell University

The structure of turbulence and of granular beds

My work centers on turbulence, both its intrinsic properties and its role in various environmental settings. Over a bed of sand, it lifts and transports the grains. Left to itself, the turbulence slowly dissipates and disappears. In the first part of my talk, I will introduce experiments motivated by the question of how quickly turbulence consumes kinetic energy. Surprisingly we do not generally know how to predict the consumption rate, though the process underlies general turbulence phenomena and modeling. What we found is that the rate is invariant with respect to changes in the intensity of the turbulence, so long as the flow is slow relative to the speed of sound. I will introduce a new experiment in which we observe how the picture changes when the flow is no longer so slow. In the second part of my talk, I describe an experiment motivated by the question of how turbulence deforms granular beds. The experiments reveal a new mechanism that produces bedforms, a mechanism associated with fluctuating pressure gradients generated in a fluid-saturated particle bed by a plate oscillating in the water above it.
Computations in Science

April 3, 2019
KPTC 206 | Wednesday, 12:15 pm

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David Weiss, The Department of Physics, Penn State University

Quantum Computing with Neutral Atoms

I will present our approach to making a quantum computer
using atoms in a 3D optical lattice. I will focus on our recent
demonstration of perfect lattice filling in 4x4x3 and 5x5x2 arrays,
which involved an experimental realization of Maxwell's demon. I will
also describe how we have accomplished high fidelity single qubit gates
(0.997) and high fidelity lossless state detection (0.9994).ost: Cheng Chin, 2-7192 or via email at cchin@jfi.uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

April 2, 2019
GCIS W301 | Tuesday, 4:00 pm

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Nan Hao, PhD. UCSD

Systems biology of single-cell aging


Biophysical Dynamics

April 2, 2019
GCIS W301 | Tuesday, 12:00 pm

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Brian M. Stoltz, California Institute of Technology

Complex Natural Products as a Driving Force for Discovery in Organic Chemistry


Bristol-Myers Squibb Lecture

April 1, 2019
GCIS W301 | Monday, 4:00 pm

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Nicholas Meanwell, Bristol-Myers Squibb

Inhibitors of HIV-1 Maturation


Bristol-Myers Squibb Lecture

April 1, 2019
GCIS W301 | Monday, 3:00 pm

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Ronak Soni, Stanford University

Scalar Asymptotic Charges and Dual Large Gauge Transformations

In recent years soft factorization theorems in scattering amplitudes have been reinterpreted as conservation laws of asymptotic charges. In gauge, gravity, and higher spin theories the asymptotic charges can be understood as canonical generators of large gauge symmetries. Such a symmetry interpretation has been so far missing for scalar soft theorems. We remedy this situation by treating the massless scalar field in terms of a dual two-form gauge field. We show that the asymptotic charges associated to the scalar soft theorem can be understood as generators of large gauge transformations of the dual two-form field. The dual picture introduces two new puzzles: the charges have very unexpected Poisson brackets with the fields, and the monopole term does not always have a dual gauge transformation interpretation. We find analogs of these two properties in the Kramers-Wannier duality on a finite lattice, indicating that the free scalar theory has new edge modes at infinity that canonically commute with all the bulk degrees of freedom.
Kadanoff Seminar

April 1, 2019
PRC 201 | Monday, 1:30 pm

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Arvind Murugan, University of Chicago

Materials that learn from examples

We usually design materials to target desired behaviors defined in a top-down manner. Learning theory offers an alternative where desired behaviors are defined by a list of examples. In learning, a material changes as it physically experiences such examples. We then test the material to see if it has the “correct” response to novel conditions never seen before (‘generalization’). Can real materials ‘learn’ from their history in this manner? We study the physical requirements for such information processing in terms of disorder, non-equilibrium driving and non-linearities using theory and experiments in disordered sheets, elastic networks, and molecular self-assembly.
Computations in Science

March 27, 2019
KPTC 206 | Wednesday, 12:15 pm

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Muhittin Mungan, University of Bonn

Cyclic Annealing, Random Maps & Memories

Disordered magnets, martensitic mixed crystals, and glassy solids can be irreversibly deformed by subjecting them to external deformation. The
deformation produces a smooth, reversible response punctuated by abrupt
relaxation ``glitches". Under appropriate repeated forward and reverse
deformation producing multiple glitches, a strict repetition of a single
sequence of microscopic configurations often emerges. It turns out that
the athermal evolution of the system configuration from glitch to glitch
can be described as a pair of maps that map states into one-another. One
map U controls forward deformation; a second map D controls reverse
deformation. The disorder of the system renders these maps random. We
will first consider iterations of a given sequence of forward and
reverse maps. Such maps necessarily produces a convergence to a fixed
cyclic repetition of states covering multiple glitches. Using numerical
sampling, we characterize the convergence properties of four types of
random maps implementing successive physical restrictions. These maps
show only the most qualitative resemblance to annealing simulations.
However, they suggest further properties needed for a realistic mapping
scheme. Formulating the irreversible part of the dynamics in terms of a
pair of maps (U,D) allows one to understand phenomena such as
return-point memory entirely in terms of the properties of these maps.
After briefly reviewing these types of features, we discuss how such a
formulation can help us in understanding the formation of memory in
matter. This is ongoing joint work with T. Witten, M.Terzi, I. Regev,
K. Dahmen and S. Sastry. Host: Thomas Witten, 2-0947 or via email at t-witten@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI Special Seminar

March 26, 2019
GCIS E223 | Tuesday, 4:00 pm

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IME Distinguished Colloquium Series - Alberto Salleo

Professor Alberto Salleo from Stanford University will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

March 20, 2019
KCBD 1103 | Wednesday, 4:00 pm

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Hana El-Samad, University of California, San Francisco

Biological control: The versatile ways in which cells use feedback loops

In 1939, Walter Cannon wrote in his book The Wisdom of the Body: “The living being is an agency of such sort that each disturbing influence induces by itself the calling forth of compensatory activity to neutralize or repair the disturbances”. Since this remarkable statement that postulates the use of feedback control to support life, we have come to appreciate that the use of feedback loops is ubiquitous at every level of biological organization, from the gene to the ecosystem. In this talk, we introduce a technology to study feedback operation in endogenous biological systems. We also discuss some recent progress in building feedback control systems with biological molecules that can modulate the operation of cellular pathways
Computations in Science

March 20, 2019
KPTC 206 | Wednesday, 12:15 pm

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Monica Allen, The Department of Physics, University of California-San Diego

Visualization of Topological States of Matter Using Microwave Impedance Microscopy

A main thrust of condensed matter physics concerns the discovery of new electronic states in emerging materials. One example is the rapidly expanding class of topological materials, which are posited to enable realization of non-abelian particles and topological quantum computing. In this talk, I will discuss how exotic phenomena can arise from the interplay of ferromagnetism and topology. We employ microwave impedance microscopy (MIM), which characterizes the local complex conductivity of a material, to directly image chiral edge modes and phase transitions in a magnetic topological insulator. Finally, I will outline how MIM could be used in the future to visualize and manipulate Majorana modes, an emerging platform for quantum information processing.Host: David Schuster at 2-7191 or David.Schuster@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu
The Tuesday JFI Seminar

March 19, 2019
GCIS W301 | Tuesday, 4:00 pm

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Raymond Kapral, University of Toronto

Molecular Machines and Synthetic Motors: Active Motion on Nanoscales

Molecular machines or motors in the cell operate under nonequilibrium
conditions and extract chemical energy from their surroundings to perform a
variety of transport and other biological functions. Synthetic nanomotors
without moving parts also operate under nonequilibrium conditions using
chemical energy to move in solution, and can transport cargo and perform
other functions. The operations of these tiny motors differ markedly from
their macroscopic counterparts. The mechanisms that lead to the directed
motion of chemically-powered motors, as well as some of their potential
applications, will be discussed. Since both molecular machines and synthetic
motors must respect the basic laws of dynamics while functioning under
nonequilibrium conditions, there are similarities between how these very
different nanomotors function. Systems containing many synthetic motors can
display collective behavior leading to active self-assembly, swarming and
other collective states that differ from those in systems at equilibrium, and
these new structures will also be described.
Chemistry

March 18, 2019
Kent 120 | Monday, 3:45 pm

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Guanyu Zhu, IBM T.J. Watson Research Center

Universal logical gate sets with constant-depth circuits for topological and hyperbolic quantum codes

A fundamental question in the theory of quantum computation is to understand the ultimate space-time resource costs for performing a universal set of logical quantum gates to arbitrary precision. To date, common approaches for implementing a universal logical gate set, such as schemes utilizing magic state distillation, require a substantial space-time overhead.

In this work, we show that braids and Dehn twists, which generate the mapping class group of a generic high genus surface and correspond to logical gates on encoded qubits in arbitrary topological codes, can be performed through a constant depth circuit acting on the physical qubits. In particular, the circuit depth is independent of code distance d and system size. The constant depth circuit is composed of a local quantum circuit, which implements a local geometry deformation, and a permutation of qubits, separated by a distance of O(d). The permutation can be implemented by moving qubits or as a constant depth circuit using long-range SWAP operations (with a range set by d) on immobile qubits. Our results apply to both the abelian stabilizer codes (such as the surface code), and also to non-abelian Turaev-Viro codes.

When applied to anyon braiding or Dehn twists in the Fibonacci Turaev-Viro code based on the Levin-Wen model, our results demonstrate that a universal logical gate set can be implemented on encoded qubits in O(1) time through a constant depth unitary quantum circuit, and without increasing the asymptotic scaling of the space overhead. Our results for Dehn twists can be extended to the context of hyperbolic Turaev-Viro codes as well, which have constant space overhead (constant rate encoding). This implies the possibility of achieving a space-time overhead of O(d/log d), which is optimal to date for generic logical circuits.

These discoveries can greatly reduce the space and time overhead of fault-tolerant quantum computation, and in particular, significantly reduce the number of physical qubits per logical qubits. From a conceptual perspective, our results reveal a deep connection between the geometry of quantum many-body states and the complexity of quantum circuits. Our scheme also demonstrates at a fundamental level the significant advantage of long-range connectivity in quantum architectures for implementing fault-tolerant quantum computation.
Kadanoff Seminar

March 18, 2019
PRC 201 | Monday, 12:00 pm

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Ramón Latorre, PhD, University of Valparaíso, Chile

Calcium- and voltage-activated (BK) channel: gating & modulation by auxiliary subunits


Biophysical Dynamics

March 14, 2019
GCIS W301 | Thursday, 12:00 pm

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Thomas Snaddon, Indiana University

Enantioselective Chemical Synthesis Methods via Cooperative Catalysis


Chemistry

March 13, 2019
Kent 102 | Wednesday, 4:00 pm

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Maciej Koch-Janusz, ETH, Zurich

Information Theory, Machine Learning and the Renormalization Group

Physical systems differing in their microscopic details often display strikingly similar behaviour when probed at macroscopic scales. Those universal properties, largely determining their physical characteristics, are revealed by the renormalization group (RG) procedure, which systematically retains ‘slow’ degrees of freedom and integrates out the rest. We demonstrate a machine-learning algorithmbased on a model-independent, information-theoretic characterization of real-space RG, capable of identifying the relevant degrees of freedom and executing RG steps iteratively without any prior knowledge about the system. We apply it to classical statistical physics problems in 1 and 2D: we demonstrate RG flow and extract critical exponents. We also prove results about optimality of the procedure.
The JFI Theory Seminar

March 13, 2019
KPTC 206 | Wednesday, 12:00 pm

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Jennifer Dionne, PhD, Stanford University

Inside Out: Visualizing chemical transformations & light-matter interactions with nanometer-scale resolution

In Pixar’s Inside Out, Joy proclaims, “Do you ever look at someone and wonder, what’s going on inside?” My group asks the same question about materials whose function plays a critical role in energy and biologically-relevant processes. This presentation will describe new techniques that enable in situ visualization of chemical transformations and light-matter interactions with nanometer-scale resolution. We focus in particular on i) ion-induced phase transitions; ii) optical forces on enantiomers; and iii) nanomechanical forces using unique electron, atomic, and optical microscopies. First, we explore nanomaterial phase transitions induced by solute intercalation, to understand and improve materials for energy and information storage applications. As a model system, we investigate hydrogen intercalation in palladium nanocrystals. Using environmental electron microscopy and spectroscopy, we monitor this reaction with sub-2-nm spatial resolution and millisecond time resolution. Particles of different sizes, shapes, and crystallinities exhibit distinct thermodynamic and kinetic properties, highlighting several important design principles for next-generation storage devices. Then, we investigate optical tweezers that enable selective optical trapping of nanoscale enantiomers, with the ultimate goal of improving pharmaceutical and agrochemical efficacy. These tweezers are based on plasmonic apertures that, when illuminated with circularly polarized light, result in distinct forces on enantiomers. In particular, one enantiomer is repelled from the tweezer while the other is attracted. Using atomic force microcopy, we map such chiral optical forces with pico-Newton force sensitivity and 2 nm lateral spatial resolution, showing distinct force distributions in all three dimensions for each enantiomer. Finally, we present new nanomaterials for efficient and force-sensitive upconversion. These optical force probes exhibit reversible changes in their emitted color with applied nano- to micro-Newton forces. We show how these nanoparticles provide a platform for understanding intra-cellular mechanical signaling in vivo, using C. elegans as a model organism.
Biophysical Dynamics

March 12, 2019
GCIS W301 | Tuesday, 12:00 pm

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William A. Tisdale, MIT

Excitons, Entropy, and Nonequilibrium Transport in Semiconductor Nanomaterials

Structure, surface chemistry, and energetic disorder can dramatically affect excited state dynamics in low-dimensional systems. Using a combination of ultrafast laser spectroscopy, time-resolved optical microscopy, and kinetic modeling, I will show how these effects manifest in assemblies of colloidal quantum dots (QD) and atomically thin 2D semiconductors, which are promising components of next-generation photovoltaic and lighting technologies. In particular, I will demonstrate the counterintuitive role of entropy in the nonequilibrium population dynamics of excitons and charge carriers in nanoscale systems.
Chemistry

March 11, 2019
Kent 120 | Monday, 3:45 pm

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Xiangfeng Duan, UCLA

Van der Waals Integration Before and Beyong 2D Materials

The heterogeneous integration of dissimilar materials is a long pursuit of material science community and has defined the material foundation for modern electronics and optoelectronics. The current material integration strategy such as chemical epitaxial growth usually involves strong chemical bonds and is typically limited to materials with strict structure match and processing compatibility. Van der Waals (vdW) integration, in which pre-fabricated building blocks are physically assembled together through weak vdW interactions, offers an alternative bond-free material strategy without lattice and processing limitations, as exemplified by 2D vdW heterostructures. In this talk I will discuss the development, challenges and opportunities of this emerging approach, generalizing it for flexible integration of diverse material systems beyond 2D, and prospect its potential for creating artificial heterostructures or superlattices beyond the reach of existing materials.
Chemistry

March 8, 2019
Kent 120 | Friday, 1:45 pm

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Frank Graziani, Lawrence Livermore National Laboratory

High Energy Density Physics and Modeling of Extreme States of Matter

High energy density physics (HEDP) is the study of matter at extreme conditions where energy densities are in excess of 10^12 ergs/cc or equivalently, pressures are in excess of 1 Mbar. HEDP spans a wide range of phenomena, from the deep interiors of the giant planets to the hot plasmas typical of stellar interiors. Matter in the HEDP regime can involve some combination of the following phenomena, collective effects, electron degeneracy, radiation, atomic kinetics, strong particle-particle correlations, non-equilibrium and hybrid quantum-classical behavior. In this overview, I will explain why HEDP is an intellectually challenging and exciting research area that impacts basic science, energy, and national security. I discuss the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) which uses the concept of inertial confinement fusion (ICF) to create conditions where pressures far exceed 1 Mbar. The remainder of the talk is devoted to an important component of executing experiments at NIF or any other HEDP facility-simulation. I discuss the spectrum of computational approaches HEDP scientists use to model their experiments. I discuss the strengths and weaknesses of the various computational approaches and briefly touch on two recent advances that may hold promise to enhancing the current weaknesses. The talk ends with a discussion of the High Energy Density Sciences Center, which is an outreach organization at LLNL that is building a HEDP community through interactions of LLNL scientists with academic collaborators.
Physics Colloquium

March 7, 2019
KPTC 106 | Thursday, 4:00 pm

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John Briggs PhD, LMB-MRC

How to assemble a retrovirus: the view from cryo-electron microscopy


Biophysical Dynamics

March 7, 2019
GCIS W301 | Thursday, 12:00 pm

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Richard Schrock, MIT

Recent Advances in Olefin Metathesis with Molybdenum Catalysts

Molybdenum imido catalysts that are asymmetric at the metal, Mo(NR)(CHR')(X)(Y), where X and Y are different monoanionic ligands (e.g., a sterically demanding terphenoxide and a chloride or pyrrolide), have led to dramatic improvements in olefin metathesis chemistry in the last two years. Advances include the synthesis of monoaryloxide (X) chloride (Y) imido catalysts, kinetically E-selective macrocyclic ring-closing metathesis catalysts, stereoselective (Z or E) olefin metathesis reactions that use electron-poor olefins (ClCH=CHCl, CF3CH=CHCF3, BrCH=CHF, NCCH=CHCN), and ROMP reactions that yield cis,syndiotactic-A-alt-B copolymers from enantiomerically pure monomers. Mo=CHX complexes where X = Cl, Br, CF3, phosphonium, or CN have now been structurally characterized. The latest results concern the synthesis of the first catalytically active molybdenum oxo alkylidene complexes through addition of water to alkylidyne complexes. Other findings will be discussed as time permits.
Hillhouse Lecture

March 4, 2019
Kent 102 | Monday, 3:45 pm

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Jennifer Lin, IAS

Entanglement in gauge theories and gravity

In this talk I’ll review how to define entanglement entropy in lattice gauge theories, and explain why an analogy between EE in emergent gauge theories and in AdS/CFT suggests that the entropy of a black hole is related to a measure on the gauge group in the bulk. I’ll then provide an explicit example of this in Jackiw-Teitelboim gravity.
Kadanoff Seminar

March 4, 2019
PRC 201 | Monday, 1:30 pm

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Jennifer Roizen, Duke University

Alcohol and Amine Derivatives Guide Position-Selective C–H Functionalization Reactions

Free radical reactions represent an important and versatile class of chemical transformations. Nitrogen-centered radical applications remain underexplored due to the lack of convenient methods for their generation. Recent advances have improved access to nitrogen-centered radicals through photoredox-mediated oxidation of two such directing groups: amides and sulfonamides. Guided by this approach, we hypothesized that alcohols, masked as sulfamate esters, and amines, masked as sulfamides, could engage in photoredox-mediated oxidation to furnish nitrogen-centered radicals that could guide C–H functionalization reactions.
Moreover, our directed technology has been inspired by one of the most reliable and powerful known reactions to guide C–H functionalization reactions: the Hofmann–Löffler–Freytag (HLF) reaction, which uses amines or amides as directing groups. Like many of the most robust radical-mediated technologies to direct the activation of tertiary and secondary centers, the HLF reaction is guided through 1,5-hydrogen-atom transfer (HAT) processes, which proceeds through a kinetically-favorable six-membered ring transition state. By contrast, few reports describe 1,6-HAT with a traceless linker, such as an alcohol masked as a sulfamate ester or an amine masked as a sulfamide, and there are no general strategies to enable masked alcohols or amines to direct functionalization of aliphatic -C(sp3)–H centers. This talk will outline this novel strategy to harness alcohols and amines to replace C–H bonds at -C(sp3)–H centers, which are not generally accessible to directed functionalization. We will demonstrate that C–H abstraction can be robustly coupled with varied functionalization reactions. This talk will highlight the first generalizable synthetic strategy to functionalize -C(sp3)–H bonds based on masked alcohols or amines, to push the boundaries of organic chemistry at a fundamental level and benefits drug discovery.
Chemistry

March 1, 2019
Kent 120 | Friday, 1:45 pm

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Jane Wang, Cornell University

Insect Flight: from Newton’s law to Neurons


Insects are the first evolved to fly, and to fly is not to fall. How does an insect fly, why does it fly so well, and how can we infer its ‘thoughts’ from its flight dynamics? We have been seeking mechanistic explanations of the complex movement of insect flight. Starting from the Navier-Stokes equations governing the unsteady aerodynamics of flapping flight, we worked to build a theoretical framework for computing flight. This has led to new interpretations and predictions of the functions of an insect’s internal machinery that orchestrate its flight. I will discuss our recent computational and experimental studies of the balancing act of insets: how a dragonfly recovers from falling upside-down and how a fly balances in air. In each case, the physics of flight informs us about the neural feedback circuitries underlying their fast reflexes.
Physics Colloquium

February 28, 2019
KPTC 106 | Thursday, 4:00 pm

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Thomas V. Magee, Senior Research Director at Pfizer

Discovery of Ketohexokinase (KHK) Inhibitor PF-06835919 for the Treatment of Fatty Liver and Metabolic Disease: From Fragments to Clinical Candidate


Chemistry

February 28, 2019
Kent 102 | Thursday, 4:00 pm

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Amy Weeks, University of California, San Francisco

New Chemoenzymatic Tools for Dissecting Proteolytic Signaling Pathways

Proteolysis is a key post-translational modification that regulates a wide array of biological processes in human health and disease, including viral infection, cancer progression, organismal development, and neurodegeneration. However, few tools are available to identify proteolysis sites with single amino acid resolution. We have developed next-generation enzymatic tools that enable unbiased capture and sequencing of neo-N termini generated by proteolytic cleavage. These probes are based on subtiligase, a rationally designed variant of the serine protease subtilisin, which catalyzes a ligation reaction between a peptide ester and the N-terminal amine of a peptide or protein. We characterized ligation efficiency for >25,000 enzyme-substrate pairs, leading to the identification of a panel of subtiligase variants that enhance sequence coverage of the cellular N terminome. We have also developed a strategy for spatially-restricted N-terminal tagging that enables global analysis of proteolytic cleavage events at the plasma membrane. Using this technique, we have sequenced proteolytic cleavage sites in >500 human membrane proteins. By combining plasma membrane-targeted subtiligase with pharmacological protease inhibitor treatment, we have begun to define the proteases responsible for specific cleavage events. In combination with its ease of use, the high specificity and resolution of live-cell, subtiligase-catalyzed proteolysis mapping provide a powerful tool for dissecting proteolytic signaling pathways.
Chemistry

February 28, 2019
GCIS W301 | Thursday, 11:00 am

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Xiang Cheng, University of Minnesota

From Flocking Birds to Swarming Bacteria: A Study of the Dynamics of Active Fluids

Active fluids are a novel class of non-equilibrium complex fluids with examples across a wide range of biological and physical systems such as flocking animals, swarming microorganisms, vibrated granular rods, and suspensions of synthetic colloidal swimmers. Different from familiar non-equilibrium systems where free energy is injected from boundaries, an active fluid is a dispersion of large numbers of self-propelled units, which convert the ambient/internal free energy and maintain non-equilibrium steady states at microscopic scales. Due to this distinct feature, active fluids exhibit fascinating and unusual behaviors unseen in conventional complex fluids. Here, combining high-speed confocal microscopy, holographic imaging, rheological measurements and biochemical engineering, we experimentally investigate the dynamics of active fluids. In particular, we use E. coli suspensions as our model system and illustrate three unique properties of active fluids, i.e., (i) abnormal rheology, (ii) enhanced diffusion of passive tracers and (iii) emergence of collective swarming. Using theoretical tools of fluid mechanics and statistical mechanics, we develop a quantitative understanding of these interesting behaviors. Our study illustrates the general organizing principles of active fluids that can be exploited for designing “smart” fluids with controllable fluid properties. Our results also shed new light on fundamental transport processes in microbiological systems.
Computations in Science

February 27, 2019
KPTC 206 | Wednesday, 12:15 pm

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Arjun Yodh, The Department of Physics & Astronomy

Soft Matter Potpourri


The Tuesday JFI Seminar

February 26, 2019
GCIS W301 | Tuesday, 4:00 pm

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Istvan Racz, University of Warsaw

On the use of evolutionary methods in spaces of Euclidean signature

Two examples of physical interest will be presented. Both, contrary to the folklore, demonstrate that evolutionary methods may also play significant role in spaces of Euclidean signature. First, the propagation of the constraints is considered. It is shown that once a clear separation of the `evolutionary’ and constraint equations is done, the subsidiary equations satisfied by the constraint expressions form a first order symmetric hyperbolic system regardless whether the ambient Einsteinian space is of Lorentzian or Euclidean signature. Second, the constraints of Einstein's theory of gravity are considered. Since the seminal observations of Lichnerowicz and York these equations are usually referred to as a semilinear elliptic system. It will be shown that–according to the choice of the dependent variables–the constraints may have different characters. In particular, they may take the form of either a parabolic-hyperbolic or a strongly hyperbolic system. Some of the recent developments related to these alternative choices will also be discussed.
Relativity Seminar

February 26, 2019
PRC 215 | Tuesday, 11:30 am

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Jessica McIver, Caltech

Gravitational wave astrophysics: a new era of discovery

Future gravitational wave observations will provide exciting new insight into key open questions in astrophysics, including the distribution of stellar remnants in the Universe, the evolution of compact binary systems, galaxy formation, the expansion of the Universe, and the explosion mechanism of core-collapse supernovae. I will highlight major outstanding challenges in gravitational wave astrophysics, including extracting transient signals from the noisy data of present and future detectors. I will present new data science techniques to address these challenges and enable future multi-messenger discoveries. I will discuss how the rapidly developing field of gravitational wave astrophysics will shape our understanding of the Universe, including the growing global interferometer network, the next generation of terrestrial interferometers, and the Laser Interferometer Space Antenna (LISA).
Relativity Seminar

February 25, 2019
PRC 201 | Monday, 3:00 pm

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Daniel Jafferis, Harvard University

Stringy ER=EPR

I will discuss how the correspondence between an entangled state of black holes and the ER wormhole spacetime can be understood as a string duality. In a pure NS background, it is a worldsheet duality involving a condensate of entangled strings. A main ingredient is the Lorentzian prescription for euclidean time winding vertex operators in angular quantization.
Kadanoff Seminar

February 25, 2019
PRC 201 | Monday, 1:30 pm

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Marc Kamionkowski, Johns Hopkins University

Heretical hypotheses in the hunt for dark matter

We have known for a reasonable fraction of a century that most of the matter in the Universe is dark, and for several decades that it cannot be baryonic. The nature of this dark matter has, however, been elusive. The prevailing weakly-interacting massive particle (WIMP) hypothesis that have long been theorists preferred guess faces considerable pressure from an array of null searches, and this has led theorists to consider previously unpalatable alternatives. I will discuss the rise, and possible fall, of an idea that connected LIGO’s discovery of black-hole binaries to dark matter. I will also discuss recent ideas (motivated in part by an intriguing recent experimental result) that involve particles with enhanced couplings to ordinary matter.
Physics Colloquium

February 21, 2019
KPTC 106 | Thursday, 4:00 pm

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Greg Voth, Wesleyan University

A new view of the dynamics of turbulence from measurements of rotations of particles with complex shapes

Non-spherical particles in turbulent flows are important in a wide range of problems including ice crystals in clouds, fibers in paper-making, marine plankton, and additives for turbulent drag reduction. We have developed experimental methods for precise tracking of the position and orientation of non-spherical particles in intense 3D turbulence. Using 3D printed particles, we can fabricate a wide range of shapes and explore how particle orientation and rotation are affected by particle shape. We find particles are strongly aligned by the turbulence. A simple picture in which particles are aligned by the fluid stretching they experience explains many of the key observations about how particles align and rotate. This same picture sheds new light on some old problems about how vorticity aligns with the strain rate tensor in turbulent flows. It has also allowed us to create a fascinating particle shape which we call a chiral dipole that shows a preferential rotation direction in isotropic turbulent flow.
Computations in Science

February 20, 2019
KPTC 206 | Wednesday, 12:15 pm

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Kenneth Schweizer, The Department of Chemistry, University of Illinois at Urbana - Champaign

Activated Dynamics in Glass Forming Colloidal, Molecular and Polymeric Liquids: From Structural Relaxation to Functional Materials

Understanding the spectacular slowing down of relaxation and mass transport in glass-forming liquids over 14 or more decades in time remains a grand scientific challenge. Moreover, many advanced materials employ viscous liquids, gels or amorphous solids in applications such as separation membranes, barrier coatings, ion-conductors and functional nanocomposites. I will present an overview of our work the past 5 years on developing a predictive, microscopic, force-based theory for activated relaxation that spans the Arrhenius, dynamic crossover and deeply supercooled regimes of colloidal, molecular and polymeric systems. The theory is based on density fluctuations as the slow variable and the trajectory-level concept of a dynamic free energy that controls intermittent motion. The irreversible re-arrangement event is of a mixed local-nonlocal character involving large amplitude hopping on the cage scale coupled to longer range collective elastic distortion of the surrounding liquid. Connections between thermodynamics, structure, dynamic elasticity and slow relaxation emerge naturally. Chemical complexity is treated based on a physically motivated coarse-graining idea that identifies a small number of key molecular parameters. Quantitative, no-fit-parameter comparisons with experiment will be presented. Generalization to the materials science problem of penetrant diffusion (gas, aromatic molecules) in polymer liquids and glasses, inspired by ideas from interstitial and polaron transport in solids, will also be discussed. Ongoing related theoretical extensions include quiescent and nonequilibrium relaxation and mechanics in attractive glass and gel-forming polymers, colloids and hybrid nanocomposite systems, large dynamical gradients in thin films, emergent anisotropic entanglement constraints and rheology of (bio)polymers, and active matter. Host: Suri Vaikuntanathan at 2-7256 or via email at svaikunt@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

February 19, 2019
GCIS W301 | Tuesday, 4:00 pm

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Ibrahim Cisse, Physics, MIT,

Super-resolution imaging of transcription in live mammalian cells


Biophysical Dynamics

February 19, 2019
GCIS W301 | Tuesday, 1:00 pm

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Kadanoff seminar: Zohar Nussinov, Washington University in St. Louis

Thermalization bounds, long range correlations, and a universal collapse of the viscosities of supercooled liquids

We will derive bounds on the equilibration times in open and closed systems. For open systems, we will find that thermalization times cannot, typically, be shorter than Planck's constant divided by the temperature; a more general (and accurate) relation involving the heat capacities will be explained. For closed systems, the inequalities that we will obtain suggest that non-adiabatically driven systems may display long range correlations. We will explain how these long range correlations appear in certain soluble models in general spatial dimensions and relate these correlations to the geometry of state manifolds. We will describe how experimental measurements of equilibrated systems may be used to infer the properties of eigenstates of many body Hamiltonians. We will then piece these results together to predict the viscosity and relaxation times of supercooled liquids and glasses. These predictions will be compared to the viscosities and dielectric relaxation times of glass formers of all known types. The comparison shows that the viscosities/relaxation times of all known supercooled liquids collapse onto a universal curve with only one (nearly uniform) liquid dependent parameter over 16 decades. The collapsed universal curve is that predicted by the theory.
Kadanoff Seminar

February 18, 2019
PRC 201 | Monday, 1:30 pm

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Jim Sethna, Cornell University

Sloppy models, differential geometry, and the space of model predictions


Models of systems biology, climate change, ecology, complex instruments, and macroeconomics have parameters that are hard or impossible to measure directly. If we fit these unknown parameters, fiddling with them until they agree with past experiments, how much can we trust their predictions? We have found that predictions can be made despite huge uncertainties in the parameters – many parameter combinations are mostly unimportant to the collective behavior. We will use ideas and methods from differential geometry and approximation theory to explain sloppiness as a ‘hyper-ribbon’ structure of the manifold of possible model predictions. We show that physics theories are also sloppy – that sloppiness may be the underlying reason why the world is comprehensible. We will present new methods for visualizing this model manifold for probabilistic systems – such as the space of possible universes as measured by the cosmic microwave background radiation.
Physics Colloquium

February 14, 2019
KPTC 106 | Thursday, 4:00 pm

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Andrei Starinets, University of Oxford

Analytic structure of hydrodynamic expansions at large finite coupling

Transport properties of liquids and gases in the regime of weak
coupling can be determined from relevant kinetic equations for
particles or quasiparticles, with transport coefficients typically
proportional to the minimal eigenvalue of the linearized kinetic
operator. At strong coupling, the same physical quantities can in
principle be found from dual gravity, where quasinormal spectra enter
as eigenvalues of the linearized Einstein's equations. We discuss the
problem of interpolating between strong and weak coupling using the
results from higher derivative gravity. We also consider the analytic
structure of all-order hydrodynamic expansions arising from the
associated complex analytic spectral curves and discuss how it is
related to the phenomenon of level crossing in quasinormal spectra of
dual black branes.
Theory Seminar

February 13, 2019
PRC 201 | Wednesday, 1:30 pm

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Jörn Dunkel, MIT

Wrinkles and spaghetti

Buckling and fracture are ubiquitous phenomena that, despite having been studied for centuries, still pose many interesting conceptual and practical challenges. In this talk, I will summarize recent experimental and theoretical work that aims to understand the role of curvature and torsion in wrinkling and fragmentation processes. First, we will show how changes in curvature can induce phase transitions [1] and topological defects [2] in the wrinkling patterns on curved elastic surfaces. In the second part, we will revisit an observation by Feynman who noted that spaghetti appears to fragment into at least three (but hardly ever two) pieces when placed under large bending stresses. Using a combination of experiments, simulations and analytical scaling arguments, we will demonstrate how twist can be used to control binary fracture of brittle elastic rods [3].

[1] Nature Materials 14, 337 (2015) [2] PRL 116: 104301 (2016) [3] PNAS 115: 8665 (2018)
Computations in Science

February 13, 2019
KPTC 206 | Wednesday, 12:15 pm

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Wei Xiong, The Department of Chemistry, University California-San Diego

Molecular Polaritons – Janus Particles of Photon and Molecules

Molecular vibrational polaritons, half-light, half-matter hybrid quasiparticles, are studied using ultrafast, coherent 2D IR spectroscopy1. Molecular vibrational-polaritons are anticipated to produce new opportunities in the photonic and molecular phenomena. Many of these developments hinge on fundamental understanding of physical properties of molecular vibrational polaritons. Using 2D IR spectroscopy to study vibrational-polaritons, we obtained results that challenge and advance both polariton and spectroscopy fields. These results invoke new developments in theory for the spectroscopy, discover observation of new nonlinear optical effects and unexpected responses from hidden dark states. We expect these results to have significant implications in novel infrared photonic devices, lasing, molecular quantum simulation, as well as new chemistry by tailoring potential energy landscapes.
1.Xiang, B. et al. Two-dimensional infrared spectroscopy of vibrational polaritons. Proc. Natl. Acad. Sci. 115, 4845–4850 (2018) Host: Prof. Andre Tokmakoff, 2-7696 or via email at tokmakoff@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email to bthomas@uchicago.edu.
The Tuesday JFI Seminar

February 12, 2019
GCIS W301 | Tuesday, 4:00 pm

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Adam Willard, MIT

The Statistical Mechanics of Hydrogen Bonding at the Liquid Water Interface

The dielectric properties of liquid water are determined in large part by the orientational fluctuations of dipolar water molecules. Near a liquid water-vapor interface these orientational fluctuations are constrained and anisotropic, leading to dielectric properties that differ significantly from their bulk values. These differences are fundamental to interface-selective chemical and physical processes but they are generally difficult to predict. We attempt to understand these differences by considering the statistical mechanics of hydrogen bonding at the liquid water interface. Using a mean-field model, we demonstrate that three-body hydrogen bond defects that are stabilized at the interface contribute significantly to determine the interfacial dielectric properties. We utilize this mean field model to study the properties of hydrophilic interfaces and then adapt this perspective to the development of an order parameter that can be used to mapping the dynamic hydration properties of proteins.
Chemistry

February 11, 2019
Kent 120 | Monday, 3:45 pm

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Dima Abanin, University of Geneva

New quantum many-body states enabled by erodicity breakdown

The experimental advances in synthetic quantum systems, such as ultracold atoms, have enabled researchers to probe quantum thermalization and its breakdown. Thermalization occurs in ergodic systems and “erases” quantum information contained in the initial many-body states. Therefore, to create long-lived quantum states, it is of particular interest to find mechanisms of thermalization breakdown. One way of suppressing thermalization is by introducing strong quenched disorder, which induces many-body localization (MBL) [1]. MBL systems exhibit a new kind of emergent robust integrability and a wealth of novel dynamical phenomena. Surprisingly, MBL systems may also avoid heating under periodic driving, which opens up the possibility of having stable, Floquet-MBL phases with unusual properties. I will discuss one example of such a phase – a two-dimensional Anomalous Floquet Insulator, characterized by fully localized bulk states and chiral, thermalizing edge states [2].

Further, I will argue that MBL may not be the only way to break ergodicity. I will propose another mechanism, “quantum many-body scarring”, which bears a similarity to the well-known phenomenon of quantum scars in few-body chaos, and leads to a weaker form of ergodicity breaking in a many-body system of Rydberg atoms [3]. Quantum scarring gives rise to a set of non-thermal many-body wave functions immersed in the thermalizing background; when the system is initialized in the physical states which have a high overlap with the non-thermal states, it exhibits many-body revivals and lack of thermalization, which have been observed in a recent experiment [4].
Kadanoff Seminar

February 11, 2019
PRC 201 | Monday, 1:30 pm

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Cathy Drennan, HHMI / MIT

Shake, Rattle, & Roll: Capturing Snapshots of Metalloproteins in Actions

Metalloproteins, or proteins that utilize metals to perform their functions, are responsible for a wide range of activities such as the conversion of greenhouse gas carbon dioxide into cellular biomass. To carry out their functions, these proteins often need to be flexible and assume different conformational states, with units of the protein swinging back and forth to enable reactants to bind the protein or products to leave. In this talk, the conformational gymnastics involved in ribonucleotide reduction are considered. Ribonucleotide reductases (RNRs) are metalloenzymes that convert ribonucleotides (the building blocks of RNA) to deoxyribonucleotides (the building blocks of DNA). RNRs are targets for cancer chemotherapies and have been proposed to be candidates for antimicrobial therapies. In this talk, I will describe how my lab has employed biophysical methods to interrogate how RNRs shake, rattle, and roll to accomplish their critical cellular function.
Women in Chemistry

February 8, 2019
Kent 120 | Friday, 1:45 pm

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Special Seminar (Particle Phenomenology): Rafaello Tito D'Agnolo, IAS

Naturalness in the Sky

Two questions have driven particle physics in the past decades and have a significance that goes beyond the domain of particle physics itself. One surrounds the nature of electroweak symmetry breaking, the other the microscopic origin of dark matter. Both have answers that seem inevitable in their simplicity, but are challenged by experimental results and contain hidden assumptions. I will present new theoretical perspectives on both questions, unveiling unexpected connections with experiment and a clear path to move forward in our understanding. Intriguingly our original expectations might be almost inverted, with dark matter more easily detectable by Earth-based accelerator experiments and electroweak symmetry breaking leaving an imprint in the Cosmic Microwave Background.

Theory Seminar

February 8, 2019
PRC 201 | Friday, 1:30 pm

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Dancing nano-particles in a strobe light

Prelude 12:00
Fugue 12:15
MRSEC Baglunch

February 8, 2019
GCIS E123 | Friday, 12:00 pm

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Vidya Madhavan, University of Illinois at Urbana–Champaign

Signatures of Dispersing 1D Majorana Channels in an Iron-based Superconductor

Dirac discovered that every fundamental particle must also have an anti-particle which has the opposite charge. When particles and anti-particles meet, they annihilate each other, releasing energy. A Majorana fermion is a special type of fundamental particle which is its own antiparticle. The possible realization of these exotic Majorana fermions as quasiparticle excitations in condensed matter physics has created much excitement. Most recent studies have focused on Majorana bound states which can serve as topological qubits. More generally, akin to elementary particles, Majorana fermions can propagate and display linear dispersion. These excitations have not yet been directly observed, and can also be used for quantum information processing. This talk is focused on our recent work in realizing dispersing Majorana modes. I will describe the conditions under which such states can be realized in condensed matter systems and what their signatures are. Finally, I will describe our scanning tunneling experiments of domain walls in the superconductor FeSe0.45Te0.55, which might potentially be first realization of dispersing Majorana states in 1D.
Physics Colloquium

February 7, 2019
KPTC 106 | Thursday, 4:00 pm

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Particle Phenomenology Seminar: Masha Baryakhtar

Searching for New Physics with Light and Gravitational Waves

Theories beyond the Standard Model often include new, light, feebly interacting particles whose discovery requires novel search strategies. The QCD axion elegantly solves the strong-CP problem of the Standard Model; axion-like-particles, dark photons, and other ultralight bosons can also appear, and are natural dark matter candidates. First, I will discuss my experimental proposal based on photonic materials, in which bosonic dark matter can efficiently convert to detectable single photons. A prototype experiment is underway, and current experimental techniques promise to reach significant new dark matter parameter space in the 0.1 − 10 eV range.

Second, I will show how the process of superradiance, combined with gravitational wave measurements, turns black holes into nature's laboratories for new ultralight boson searches. When a bosonic particle's Compton wavelength is comparable to the horizon size of a black hole, superradiance converts energy and angular momentum from the black hole into exponentially growing `hydrogenic' bound states of bosons. I will present constraints on axions and dark photons from black hole spin measurements, and discuss how these systems may source up to thousands of monochromatic gravitational wave signals, enabling LIGO to discover new particles.
Kadanoff Seminar

February 6, 2019
PRC 201 | Wednesday, 1:30 pm

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Andrej Košmrlj, Princeton University

Phase separation in multicomponent liquid mixtures

Multicomponent systems are ubiquitous in nature and industry. While the physics of binary and ternary liquid mixtures is well-understood, the thermodynamic and kinetic properties of N-component mixtures with N>3 have remained relatively unexplored. Inspired by recent examples of intracellular phase separation, we investigate equilibrium phase behavior and morphology of N-component liquid mixtures within the Flory-Huggins theory of regular solutions. In order to determine the number of coexisting phases and their compositions, we developed a new algorithm for constructing complete phase diagrams, based on numerical convexification of the discretized free energy landscape. Together with a Cahn-Hilliard approach for kinetics, we employ this method to study mixtures with N=4 and 5 components. In this talk I will discuss both the coarsening behavior of such systems, as well as the resulting morphologies in 3D. I will also mention how the number of coexisting phases and their compositions can be extracted with Principal Component Analysis (PCA) and K-Means clustering algorithms. Finally, I will discuss how one can reverse engineer the interaction parameters and volume fractions of components in order to achieve a range of desired packing structures, such as nested "Russian dolls" and encapsulated Janus droplets.
Computations in Science

February 6, 2019
KPTC 206 | Wednesday, 12:15 pm

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Emily Weiss - The Department of Chemistry, Northwestern University

Regio- and Diastereoselective Triplet-Initiated Intermolecular [2+2] Cycloadditions Photocatalyzed by Visible-light-Absorbing Quantum Dots

Tetrasubstituted cyclobutyl structures are precursors to, or core components of, many important bioactive molecules, including prospective drugs. Light-driven [2+2] cycloaddition is the most direct strategy for construction of these structures. Synthetic applications of [2 + 2] photocycloadditions demand high selectivity, not only for specific coupling products, but also for particular stereo- and regioisomers of those products. Achieving selectivities for (i) a particular regioisomer of the coupled product, (ii) a particular diastereomer of the coupled product, and (iii) homo- vs. hetero-coupling within a mixture of reactive olefins still remains a challenge. Here, we discuss the use of colloidal CdSe quantum dots (QDs) as visible light absorbers, triplet exciton donors, and scaffolds to drive homo- (photodimerization) and hetero- (cross coupling) intermolecular [2+2] photocycloadditions of 4-vinylbenzoic acid derivatives, with >90%, switchable regioselectivity and up to 98% diastereoselectivity for the previously minor syn-head-to-head (HH) or syn-head-to-tail (HT) configurations of the adducts. The diasteromeric ratios (d.r.) we achieve are a factor of 5 - 10 higher than those reported with all other triplet sensitizers. Furthermore, the size-tunable triplet energy of the QD enables regioselective hetero-intermolecular couplings through selective sensitization of only one of the reagent olefins. This is the first example of chemistry driven by triplet-triplet energy transfer from a QD. Host: Rachael Farber via email at rgf33@uchicago.edu . If you need assistance, please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu
The 1st Tuesday JFI Colloquium

February 5, 2019
GCIS W301 | Tuesday, 4:00 pm

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Tania Baker, Department of Biology, Massachusetts Institute of Technology

AAA+ Unfoldase Motors: Regulators of the Proteome as Activators and Destroyer of Protein Function


Biophysical Dynamics

February 5, 2019
GCIS W301 | Tuesday, 1:00 pm

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Particle Phenomenology Seminar: Zhen Liu

A pathway to the next discovery

The discovery of the Higgs boson at CERN LHC marks the triumph of 50 years of endeavor of high energy physics. The Higgs discovery is only possible with a joint force between experimentalists and theorists in a phenomenological approach. The phenomenological approach and the Higgs boson itself light the pathway towards the next discovery. In this seminar, I will present my recent work that changes the perspective of the LHC main detectors in searches for a challenging class of new physics signals--long-lived particles (LLPs). The new physics signals are well-motivated by broad categories of new physics models, such as supersymmetry and hidden sector models. I will first identify the advantages of the LHC in comparison with other satellite experiments and then present our novel proposals with new triggers and analysis strategies to fully realize such strength, in close connection with the upcoming detector upgrades with precision timing and high granularity detectors. If time permits, I will briefly discuss a few attempts to probe new physics through novel table-top and non-collider experiments along this path. Finally, I will conclude with a broader picture of the pathway to the next discovery.
Theory Seminar

February 4, 2019
PRC 201 | Monday, 4:00 pm

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Kharasch Mini Symposium

2:15 pm - Todd Hyster (Princeton) https://www.hysterlab.com/
2:50 pm - Ellen Sletten (UCLA) http://sletten.chem.ucla.edu/
3:25 pm - Mingji Dai (Purdue) http://www.chem.purdue.edu/dai/
4:00 pm - Coffee Break
4:15 pm - Carolyn Bertozzi (Stanford) https://bertozzigroup.stanford.edu/
Chemistry

February 4, 2019
GCIS W301 | Monday, 2:15 pm

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Hannes Pichler, Harvard

From many-body physics to quantum information with atomic and photonic systems

Quantum many-body systems have unique properties that give rise to fascinating phenomena and potential applications, ranging from exotic phases of matter to new paradigms for information processing and communication. Novel technological developments in quantum optical systems allow to realize and study complex quantum many-body systems in a controlled way. In this talk I want to discuss examples that highlight how the tools available to control quantum optical system can be employed to bring abstract theoretical concepts to the laboratory, but also pose new theoretical challenges in describing such systems. To this end I will first discuss the physics of arrays of individually trapped Rydberg atoms [1] and the associated quantum many-body phenomena. This includes the equilibrium quantum phase diagram in 1D and the universal quantum critical behavior of the various accessible quantum phase transitions, as well as novel non-equilibrium phenomena such as quantum many-body scars. Moreover I show how these systems can be used to naturally encode combinatorial optimization problems and realize quantum annealers [2]. In the second part of this talk I focus on atom-photon interfaces and present a novel way to create highly entangled states of photons by sequentially generating and correlating photons using a single quantum emitter in a waveguide QED setting. I show that employing novel concepts, such as delayed quantum feedback dramatically expands the class of achievable photonic quantum states and allows to generate states that are universal resources for quantum computation with minimal experimental resources [3].



Kadanoff Seminar

February 4, 2019
PRC 201 | Monday, 1:30 pm

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Special Seminar (Particle Phenomenology): Andrea Thamm, CERN

Beyond the Standard Model: Beyond the LHC

After an introduction to the Standard Model (SM) of Particle Physics and the Large Hadron Collider, I discuss some open questions in the SM, focussing in particular on the hierarchy problem and dark matter. I then describe three theoretical directions which address these open problems: heavy new physics, light new physics and models of dark matter. I discuss their motivations, basic setup and the role future colliders could play in their discovery.
Theory Seminar

February 1, 2019
PRC 201 | Friday, 1:30 pm

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Peggy Mason, University of Chicago

Empathy: The good, the bad, and the ugly

Both the benefits of empathy and the exceptional human qualities needed to exhibit empathy are widely touted in popular culture. Yet rats appear to act out of other-oriented concern, a putative rat analog of empathy, by releasing a fellow rat that is trapped in a tube. This finding shows that empathically driven helping is not restricted to humans and is a process that occurs in other mammals including rats. Empathic helping is proximally driven by the reinforcing consequences of the act of helping which is rewarding so that helping “feels good.” Nonetheless, empathic helping requires both emotional caring and the ability to down-regulate one’s own emotions. Thus, empathic helping is resource-depleting and can be personally costly. This ultimately drives the selective application of empathic helping to in-group members. Finally, rats appear to be more reinforced by releasing a trapped rat than by seeing a trapped rat receive help, suggesting that the act of helping is more rewarding than is the relief of distress. The dissociation between active helping and help received suggests that those who take actions intended to help may be receiving a reward that may be incommensurate with the help that is in fact received. This can lead individuals to falsely perceive their actions as helpful; Such falsehoods can be counterproductive in the context of medicine, leading physicians who actively treat patients to consider a problem resolved when it is not.
Physics Colloquium

January 31, 2019
KPTC 106 | Thursday, 4:00 pm

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Kadanoff Special Seminar: Gil Young Cho, Postech

Many-Body Invariants for Multipoles in Higher-Order Topological Insulators

We propose many-body invariants for multipoles in higher-order
topological insulators by generalizing Resta's pioneering work on
polarization. The many-body invariants are designed to measure
multipolar charge distribution in a crystalline unit cell, and they
match the localized corner charge originating from the multipoles. We
provide analytic arguments and numerical proof for the invariants.
Furthermore, we show that the many-body invariants faithfully measure
the physical multipole moments even when the nested Wilson loop
approaches fail to do so.
Kadanoff Seminar

January 31, 2019
PRC 201 | Thursday, 3:30 pm

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Nichole Yunger Halpern, Harvard

Quantum steampunk: Quantum information meets thermodynamics

Thermodynamics has shed light on engines, efficiency, and time’s arrow since the Industrial Revolution. But the steam engines that powered the Industrial Revolution were large and classical. Much of today’s technology and experiments are small-scale, quantum, and out-ofequilibrium. Nineteenth-century thermodynamics requires updating for the 21st century. Guidance has come from the mathematical toolkit of quantum information theory. Quantum information theory describes how we can use nonclassical phenomena (entanglement, uncertainty, discreteness, etc.) to process information in ways impossible with classical hardware. Applying quantum information theory to thermodynamics sheds light on fundamental questions (e.g., how does entanglement spread during quantum thermalization?) and suggests new technologies (e.g., quantum engines). I will overview how quantum information theory can modernize thermodynamics for quantum-information-processing technologies, then will focus on thermalization in quantum many-body systems. I call this combination quantum steampunk, after the steampunk genre of literature, art, and cinema that juxtaposes futuristic technologies with 19th-century settings.
Kadanoff Seminar

January 31, 2019
PRC 201 | Thursday, 1:30 pm

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Bryan Dickinson, University of Chicago

Synthetic Biology Approaches to Study and Exploit RNA Regulation

RNA controls information flow through the central dogma and provides unique opportunities for manipulating cells. However, both fundamental understanding and potential translational applications are impeded by a lack of methods to study and exploit the regulation of RNA. Here, I will present three vignettes on our recent protein engineering and molecular evolution efforts focused on understanding and controlling RNA. First, I will show how our engineered RNA polymerase-based biosensors can be exploited as a new method to harness rapid molecular evolution to solve problems in molecular recognition. Second, I will unveil a new evolution system for creating reverse transcriptases that encode RNA modifications in mutations, which allow us to catalog the precise locations of a poorly-understood RNA methylation modification in mammalian cells. Finally, I will present CRISPR/Cas-inspired RNA targeting system (CIRTS), a new protein engineering strategy for constructing programmable RNA regulatory systems, built entirely from human protein parts. Collectively, our technology development focused around RNA regulation will continue to shed light on how mammalian cells function at a fundamental level, while also opening up new opportunities in molecular evolution and epitranscriptomic biotechnology development.
Chemistry

January 31, 2019
GCIS W301 | Thursday, 1:15 pm

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Particle Phenomenology Seminar: Simon Knapen

Searching for whispers from beyond the standard model

Searches for high energy signatures from beyond the standard model physics have advanced greatly, but a lot of ground remains to be covered for soft, low energy signals. At the LHC, searches for long-lived particles are such an example, as qualitative gains are possible by making full use of the LHCb cavern in the phase II upgrade. In the context of dark matter direct detection, future single-phonon detectors will be sensitive to dark matter with a mass as low as roughly 10 keV. In this regime, the conventional nuclear recoil picture no longer applies and new theoretical tools are needed to correctly compute the scattering rate. I will discuss the prospects for detector concepts based on superfluid helium and polar material targets, where in the latter case we find a large daily modulation of the scattering rate.
Theory Seminar

January 30, 2019
PRC 201 | Wednesday, 1:30 pm

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Arthur Barnard, Stanford University

New tools for probing classical and quantum nanomaterials

In this seminar, I will discuss two domains of condensed matter physics elucidated by new tools: thermal motion in nanomechanical structures and quantum electron transport in 2D materials. By picking up individual carbon nanotubes and coupling them with electrostatic gates and optical cavities, we directly read-out non-equilibrium dynamics and observe real-time Brownian motion. We reveal surprising spectral dynamics obscured by existing measurement techniques, shedding light on the physics behind the unexpectedly low quality-factor in room temperature carbon nanotube resonators. In the second part of this seminar, I will explain how we control the flow of electrons in graphene. Drawing from intuitions in ballistic transport and light optics, we produce collimated electron beams to quantitatively study angularly dependent phenomena such as Klein tunneling, and elucidate how electrons start to behave like a fluid as they interact more strongly with each other. Using scanning gate microscopy, we image how electrons can follow non-circular cyclotron orbits in graphene-based superlattices.
Special JFI Seminar

January 29, 2019
KPTC 206 | Tuesday, 1:30 pm

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Gurol Suel, University of California San Diego

The resilience & dichotomy of bacterial existence


Biophysical Dynamics

January 29, 2019
GCIS W301 | Tuesday, 12:00 pm

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Jennifer Lippincott-Schwartz, HHMI

Peering Into Cells with New Imaging Technologies

Powerful new ways to image the internal structures and complex dynamics of cells are revolutionizing cell biology and bio-medical research. In this talk, I will focus on how emerging fluorescent technologies are increasing spatio-temporal resolution dramatically, permitting simultaneous multispectral imaging of multiple cellular components. Using these tools, it is now possible to begin constructing an “organelle interactome” describing the interrelationships of different cellular organelles as they carry out critical functions. The same tools are also revealing new properties of the cell’s largest organelle, the endoplasmic reticulum, and how disruptions of its normal function due to genetic mutations may contribute to important diseases. Results from these and other technologies that significantly increase spatial resolution in 3-D, including focused ion beam scanning electron microscopy, will be presented.
Chemistry

January 28, 2019
Kent 120 | Monday, 4:00 pm

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Hoi Chun Po, MIT

Symmetry shortcuts to topological materials

The discovery of topological insulators unveiled a new class of quantum materials whose physical properties are crucially determined by the interplay between symmetries and topology. In this talk, I will discuss how this discovery points to a natural revision of the paradigm of symmetry analysis of weakly correlated materials. Within this new framework, we further develop a general theory for the diagnosis and classification of topological crystalline materials. Our theory integrates theoretical insights originating from the formal classification of topological phases with conventional first-principles calculations, which enables us to efficiently identify thousands of topological materials candidates scattered across the 230 space groups.
Kadanoff Seminar

January 28, 2019
PRC 201 | Monday, 1:30 pm

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A surface-grafted polymer brush that can flip a nematic fluid, then flip it back.

Let us dine 12:00
Let us opine 12:15
MRSEC Baglunch

January 25, 2019
GCIS E123 | Friday, 12:00 pm

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Pablo Jarillo-Herrero, Massachusetts Institute of Technology

Magic Angle Graphene: a New Platform for Strongly Correlated Physics

The understanding of strongly-correlated quantum matter has challenged physicists for decades. Such difficulties have stimulated new research paradigms, such as ultra-cold atom lattices for simulating quantum materials. In this talk I will present a new platform to investigate strongly correlatedphysics, based on graphene moiré superlattices. In particular, I will show that when two graphene sheets are twisted by an angle close to the theoretically predicted ‘magic angle’, the resulting flat band structure near the Dirac point gives rise to a strongly-correlated electronic system. These flat bands exhibit half-filling insulating phases at zero magnetic field, which we show to be a correlated insulator arising from electrons localized in the moiré superlattice. Moreover, upon doping, we find electrically tunable superconductivity in this system, with many characteristics similar to high-temperature cuprates superconductivity. These unique properties of magic-angle twisted bilayer graphene open up a new playground for exotic many-body quantum phases in a 2D platform made of pure carbon and without magnetic field. The easy accessibility of the flat bands, the electrical tunability, and the bandwidth tunability though twist angle may pave the way towards more exotic correlated systems, such as quantum spin liquids or correlated topological insulators.
Physics Colloquium

January 24, 2019
KPTC 106 | Thursday, 4:00 pm

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Shenshen Wang, Physics & Astronomy, UCLA

Discovering generalist solutions in rough & changing landscapes

Evolving systems, be it an antibody repertoire in the face of mutating pathogens or a microbial population exposed to varied antibiotics, respond to ever changing environments through a constant search for adaptive solutions in high-dimensional fitness landscapes. Generalists are robust performers in varied environmental conditions. For better (induction of broad antibody response) or worse (emergence of multi-drug resistance), it is important to be able to discover these adaptive solutions efficiently. Yet, whether and when environmental changes can grant evolutionary advantage to generalists in the long run remains elusive. We introduce a generic landscape framework to study the evolutionary discovery of generalist solutions in slowly changing environments. We show that alternation between rugged fitness landscapes can enhance the propensity to evolve fit generalists, if the landscapes’ topography balances a tradeoff between prevalence, fitness and accessibility, thus demonstrating a general route toward favoring or avoiding generalists via a proper choice of alternating environments. This has important implications for speeding up the generation of broadly neutralizing antibodies or preventing microbes from evolving multi-drug resistance.
Biophysical Dynamics

January 24, 2019
GCIS W301 | Thursday, 1:00 pm

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Shmuel Rubinstein, Harvard

The physics of crushing and smashing: Cascades and cataclysmic change

Many of the big problems we are facing involve far from equilibrium systems that entail a cataclysmic change. Climate, turbulence and earthquakes, developmental biology, evolution and even aging and death. These phenomena are rare (sometimes occurring only once) and are entirely irreversible. While understanding the physics of such irreversible processes is of both fundamental and practical importance, these problems also pose unique challenges. These challenges, as they manifest in turbulence, were beautifully portrayed by Richardson:

“Big whirls have little whirls that feed on their velocity, and little whirls have lesser whirls and so on to viscosity” Lewis Fry Richardson (1922)

In his short verse, Richardson captures the essence of the turbulent cascade—the conveyance of kinetic energy across scales that underlies the universal dynamics of turbulent flows. Indeed, such conveyance of important physical quantities (energy, stress, frustration and even information) down and up a vast range of scales underlines the dynamics of many systems. The same applies to how a multi-contact frictional interface will form and break or how correlated defect structures determine the strength of a space-rocket, how an intricate network of creases will form when we crumple a thin sheet or when soda can is smashed. The challenge in understanding these systems is in capturing the events as they occur, keeping up with the dynamics on all scales and at all times. Here, I will review our work on several key irreversible system and introduce the new tools we developed to address their unique evolution and discuss the interesting physics we learned.
Computations in Science

January 23, 2019
KPTC 206 | Wednesday, 12:15 pm

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Andrew Potter, Honeywell

Entanglement dynamics and topology in driven systems

Dramatic advances in AMO systems and ultra-fast optics have assembled a powerful toolbox for coherently and time-dependently manipulating quantum many-body systems, raising enticing prospects for engineering phases of quantum materials and developing quantum information processing technology. However, conventional wisdom dictates that driven many-body systems should follow the principles of eigenstate thermalization, behaving chaotically and rapidly scrambling stored quantum information.
Surprisingly, this trend can be thwarted by artificially disordering isolated systems to selectively freeze dissipative processes that cause thermalization while enabling long-lived quantum coherent dynamics -- a phenomena dubbed many-body localization (MBL). Driving MBL systems enables new non-equilibrium "phases" of matter with stable dynamical quantum properties that are not possible in equilibrium. This talk will describe how developing new tools to characterize the topology and dynamics of quantum entanglement in MBL systems has enabled substantial progress towards systematically classifying these dynamical phases, understanding their signatures, and designing experimental realizations.
Kadanoff Seminar

January 22, 2019
PRC 201 | Tuesday, 3:00 pm

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Special Seminar (Particle Phenomenology): Prateek Agrawal

Axions at the discovery frontier

The next decade will push the boundary of our understanding of fundamental physics in a number of directions, potentially culminating in new discoveries. I will describe how new theoretical insights are pushing this discovery frontier forward. After a broad overview, I will focus on recent progress in axion physics. Axions are compelling candidates for new physics, and traditional axion models predict a relatively narrow target for experiments. I will present novel mechanisms in cosmology and quantum field theory that broaden this parameter space significantly, motivating new experiments. Such an extension of our search strategy may prove crucial to the discovery of axions.
Theory Seminar

January 18, 2019
PRC 201 | Friday, 3:00 pm

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Edbert Sie, Stanford

How to Control Quantum Materials with Light

A primary goal of modern condensed matter physics is to discover novel quantum phases of matter and engineer their properties. However, conventional approaches using material synthesis or static electromagnetic fields have enabled only a limited exploration of the phase space and associated symmetries at thermal equilibrium. In this talk, I will discuss how we use light to manipulate the space-time symmetries in materials and discover new quantum phenomena that were previously inaccessible. First, I will show that breaking time-reversal symmetry with light enables us to lift the pseudospin degeneracy in monolayer WS2 and selectively tune their energy levels. Here we can completely disentangle the fundamental light-matter interaction into two previously inseparable quantum processes known as the optical Stark effect and the Bloch-Siegert shift. Second, I will show that manipulating inversion symmetry with light allows us to induce topological phase transitions in the Weyl semimetal WTe2 through strain-tuning the lattice. The induced atomic displacements were crystallographically measured using relativistic electron diffraction at sub-picometer length scale and sub-picosecond time scale. These results offer nonequilibrium pathways for designing tunable quantum properties towards terahertz electronics, quantum information, and energy conversion technologies.
JFI Special Seminar

January 18, 2019
KPTC 206 | Friday, 1:30 pm

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Odd elasticity: soft engines from active solids

Food eaten 12:00
Thoughts spoken 12:15
MRSEC Baglunch

January 18, 2019
GCIS E123 | Friday, 12:00 pm

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Dominic Else, MIT

Topological phases of matter with spatial symmetries

A topological phase is a phase of matter characterized by a non-trivial long-wavelength pattern of quantum entanglement in the ground state of a strongly interacting quantum many-body system. I will describe a very general approach to understand such phases in the presence of spatial symmetries such as translation, rotation and reflection (such phases are often referred to as "crystalline topological phases"). There are several complementary ways to think about this approach, one of which is based on a systematization of the notion of gauging a spatial symmetry; I will also outline a more concrete geometrical picture in terms of "defect networks". Finally, I will show how this new understanding of crystalline topological phases allows for the unification and generalization of results such as the Lieb-Schultz-Mattis theorem for quantum spin systems, which can be reinterpreted as a kind of UV-IR anomaly matching in the presence of a spatial symmetry.
Kadanoff Seminar

January 17, 2019
PRC 201 | Thursday, 1:30 pm

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Special Seminar (Particle Phenomenology): Yue Zhang

New Dark Matter Signals in Neutrino Detectors

Understanding the nature of dark matter is a question lying at the heart of particle physics and cosmology. I will discuss the potential leading role of using our current and near future neutrino experiments in search for a class of dark matter candidates, and a number of associated new signals. With the new generation of neutrino detectors in the coming decade, many ideas can be tested. The complementarity with the other approaches will also be discussed in this talk.
Theory Seminar

January 16, 2019
PRC 201 | Wednesday, 2:00 pm

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Eric Spanton, UC Santa Barbara

Fractional Chern insulators in graphene heterostructures

Graphene is a highly tunable platform for studying the effects of electron-electron interactions in two dimensions. Encapsulation with a 2D dielectric (hexagonal boron nitride, hBN), and more recently the use of single-crystal graphite top and bottom gates have decreased the electronic disorder to a level suitable for the to study fragile and exotic strongly correlated states. Additionally, control of twist angle between closely-matched crystal lattices allows for unique control of electronic properties, leading to the “Hofstadter butterfly” and more recently unconventional superconductivity. I will describe the first experimental observation of a class of states in nearly aligned hBN/graphene heterostructures called fractional Chern insulators, a close relative of the fractional quantum Hall effect. In graphene, fractional Chern insulators arise in the presence of electron-electron interactions, high magnetic fields, and a long wavelength ‘moire’ superlattice formed by close alignment between hBN and graphene lattices. Twist angle between graphene and hBN, electron density and perpendicular electric field tune the underlying single-particle bands to realize different types of fractional Chern insulators. The realization of fractional Chern insulators opens the door for the study of novel topological phase transitions and exotic defect states.
JFI Special Seminar

January 16, 2019
KPTC 206 | Wednesday, 1:30 pm

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Margaret Gardel, University of Chicago

Controlling the Shape of Cells within Tissue

Mature epithelial tissues have distinct cellular architecture, which is maintained despite externally applied forces, wounding, and cell division or death. Here we investigate how a model tissue develops and maintains cellular structure by quantifying single cell dynamics and cell shape in newly formed monolayers of MDCK cells. Cells initially aggregate through a process resembling wound healing into a confluent monolayer with elongated cells that remain motile. After formation, individual monolayers evolve over time to reach a similar final state with more hexagonal cell shapes and arrested dynamics, resembling mature epithelial tissues. By quantifying cell trajectories, we observe glassy dynamics controlled by cell shape, which have been previously predicted by vertex models. On substrates of different stiffness, monolayers form and evolve with different cell number density but the same relationship between cell shape and speed suggesting that the dynamics are density independent. We find when inhibiting several regulators of the actin cytoskeleton that cell speed and shape remain correlated but the correlation is shifted toward more elongated cell shapes. The magnitude of this shift differs for each inhibitor but velocity correlation length decreases proportionately to the change in final cell shape. We show that these results can be recapitulated in vertex models which incorporate polarization coupling between neighboring cells. Our results demonstrate that multicellular coordination of cell motility plays an important role in regulation of cell shape and determination of final tissue structure.
Computations in Science

January 16, 2019
KPTC 206 | Wednesday, 12:15 pm

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Ke Xu, Department of Chemistry, University of California-Berkeley

Multifunctional & Multidimensional Super-resolution Microscopy

Recent advances in super-resolution fluorescence microscopy have led to ~10 nm spatial resolution and exciting new biology. We are developing new approaches to advance beyond the structural (shape) information offered by existing super-resolution methods, and reveal multidimensional information of intracellular functional parameters, including chemical polarity, diffusivity, and reactivity, with nanoscale resolution and single-molecule sensitivity. By adding remarkably rich functional dimensions to the already powerful super-resolution microscopy, we thus open up new ways to reveal fascinating local heterogeneities in live cells. Host: Bozhi Tian, 2-8749 or via email at btian@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

January 15, 2019
GCIS W301 | Tuesday, 4:00 pm

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Ryo Nakano, Nagoya University

Study on Olefin Polymerization Toward Utilization of Carbon Dioxide

Although carbon dioxide has attracted broad interest as a renewable carbon feedstock, its favorable nature as a carbon source is inextricably linked to its inherent inertness. Therefore, to overcome the endothermic penalty of carbon-dioxide incorporation, a transformation of carbon dioxide under mild conditions requires a thermodynamic driving force from coupling partners. In this context, copolymerization of carbon dioxide and olefin, which is the largest class of organic chemicals produced today, will be a suitable reaction exploiting the prospective features of carbon dioxide as a C1 bulk feedstock.
From a theoretical consideration on the thermodynamics of olefin/carbon dioxide copolymerization, stepwise and direct copolymerization were investigated. The stepwise approach was successfully demonstrated in butadiene/carbon dioxide copolymerization via a lactone intermediate, as the first example to prepare high-molecular-weight copolymer starting from a bulk alkene and carbon dioxide. For further expansion of the scope of olefins toward monoenes, namely ethylene and propylene, palladium catalyst bearing an NHC-based bidentate ligand (IzQO) was designed rationally. While the CO2/monoene copolymerization was not accomplished, the palladium/IzQO complexes exhibited unique catalytic activities for propylene/polar monomer copolymerization and ethylene/1,1-disubstituted olefin copolymerization.
Chemistry

January 14, 2019
Kent 120 | Monday, 3:00 pm

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Why do my flying lego blocks spin and make hinges?

Eatin' time 12:00
Thinkin' time 12:15
MRSEC Baglunch

January 11, 2019
GCIS E123 | Friday, 12:00 pm

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Reina Maruyama, Yale University

Testing DAMA's Long-standing Claim for Dark Matter Detection

Astrophysical observations give overwhelming evidence for the existence of dark matter. Several theoretical particles have been proposed as dark matter candidates, including weakly interacting massive particles (WIMPs), axions, and more recently their much lighter counterparts, however there has not yet been a definitive detection of dark matter. One group, the DAMA collaboration, has asserted for years that they observe a dark matter-induced annual modulation signal in their NaI(Tl)-based detectors. Their observations seem to be inconsistent with those from other direct detection dark matter experiments under most assumptions of dark matter. In this talk I will describe the current status of the debate and the world-wide experimental effort to test this extraordinary claim. I will report the recent results from the COSINE-100 experiment and our progress toward resolving the current stalemate in the field.
Physics Colloquium

January 10, 2019
KPTC 106 | Thursday, 4:00 pm

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Andrew Feguson, Institute for Molecular Engineering, The Univeristy of Chicago

Machine Learning Collective Variable Discovery in Colloidal Assembly and Protein Folding

Data-driven modeling and machine learning have opened new paradigms and opportunities in the understanding and design of soft and biological materials. The automated discovery of emergent collective variables within high-dimensional computational and experimental data sets provides a means
to understand and predict materials behavior and engineer properties and function. I will describe our recent work in the use of two machine learning techniques for collective variable discovery within molecular simulation – nonlinear manifold learning using diffusion maps, and nonlinear dimensionality reduction using autoencoding neural networks (“autoencoders”). First, I will describe our applications of graph matching and diffusion maps to determine low-dimensional assembly landscapes for self-assembling patchy colloids. These landscapes connect colloid architecture and prevailing conditions with
emergent assembly behavior, and we use them to perform inverse building block design by rationally sculpting the landscape to engineer the stability and accessibility of desired aggregates. Second, I will describe our use of autoencoders to perform automated discovery of collective variables in proteinfolding. We interleave deep learning variable discovery and enhanced sampling directly within the discovered variables to perform simultaneous on-the-fly variable discovery and accelerated sampling of protein folding funnels.Host: Suri Vaikuntunathan, 2-7256 or via email to svaikunt@uchicago.edu. Persons with a disability who need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

January 8, 2019
GCIS W301 | Tuesday, 4:00 pm

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Su-Yang Xu, MIT

Topology and Geometry in Quantum Materials

Finding new phases of matter and understanding their physics are primary goals of condensed matter physics. Advances in quantum physics can in turn breed novel technologies, benefiting our society. Topological states are new phases of matter characterized by a nonzero topological invariant. They can support protected surface/edge states, realize elusive particles, and respond to electric and magnetic fields in unconventional ways. On a more fundamental level, topological physics arise from the geometric properties of the quantum wavefunction, i.e., quantum geometry, which include Berry curvature, Berry connection, quantum metric, etc.



First, I will describe how we search for material platforms that support new topology and quantum geometry. In particular, I will focus on our theoretical predictions and experimental observations of the first Weyl fermion semimetal state in TaAs and later the topological chiral crystal state in RhSi. Second, I will describe nonlinear optoelectronic and transport measurements that can probe Berry curvature and interaction in a symmetry-sensitive way. Specifically, I will show how we use mid-infrared photocurrents to probe the chirality of Weyl fermions and other Berry curvature physics in 3D and 2D topological materials. I will also show our photocurrent detection of a novel electronic instability, the gyrotropic order, in the correlated semimetal TiSe2, and how we use circularly polarized light to manipulate such order via quantum geometrical responses. In the final part, I show how current works suggest ample new exciting possibilities to discover fundamental physics in topological condensed matter physics, which also offers pathways to quantum sensing, information and computation technologies.


Special JFI Seminar

January 8, 2019
KPTC 206 | Tuesday, 1:30 pm

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Marc-André Légaré, University of Würzburg

Main-Group Metallomimetics: Strategies for Metal-Free Catalysis and Small-Molecule Activation

The importance of transition metals (TMs) in modern catalysis cannot be overstated. TM-based catalysts enable processes that are of tremendous human and economic importance; they have innumerable applications in many industrial sectors. However, the toxicity, price and natural scarcity of many elements that are used in TM catalysis fuel an interest for the development of metal-free catalysts based on the main-group elements.
However, contrary to many catalytically-active TM complexes, classical main-group compounds do not possess the combination of empty and filled orbitals that is crucial for the complex electronic processes involved in the elemental steps of catalytic cycles. The development of catalysts based on the p-block elements thus requires the design and application of unique strategies. In this seminar, I will present two approaches for the metallomimetic application of boron compounds to small-molecule activation, to reduction processes, and to organic functionalization reactions. I will discuss systems that involve the combination of single and multiple active sites in order to mimic the electronic environment of TM complexes. Similarities and differences in the reactivity of main-group compounds and TM complexes will also be highlighted.
Chemistry

January 7, 2019
Kent 102 | Monday, 3:00 pm

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Katharine Diehl, Princeton University

Illuminating Epigenetic Mechanisms in Cancer with Designer Chromatin

In the eukaryotic cell, the genome is packaged in a nucleoprotein complex known as chromatin. Histones comprise the protein component of chromatin and serve as a hot bed for post-translational modifications (PTMs) that dynamically modulate local chromatin state to control DNA transcription, replication, and repair. Importantly, cancer cells depend on altered epigenetic landscapes to drive genomic instability and aberrant gene expression. In order to precisely target epigenetic misregulation in disease, it is critical to elucidate the mechanistic basis of how specific chromatin states are established and maintained. This talk will discuss how synthetic access to defined chromatin substrates enables the discovery of mechanisms by which histone PTMs modulate the genome. In the first part, a DNA-barcoded mononucleosome library was used to profile the activity of crucial DNA damage sensor enzymes (PARP1/2), uncovering new regulatory features in the DNA damage response. In the second part, designer chromatin substrates were used to investigate an oncogenic histone mutant, revealing details of how this mutation leads to deleterious epigenetic reprogramming. These efforts demonstrate how protein chemistry can be integrated with biochemical, biophysical, and genetic tools to facilitate analysis of the physicochemical principles underlying epigenetic dysregulation.
Chemistry

January 4, 2019
Kent 102 | Friday, 1:15 pm

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winner take all: from neural networks to nucleation

Gala reception 12:00
Gala discussion 12:15
MRSEC Baglunch

January 4, 2019
GCIS E123 | Friday, 12:00 pm

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Paola Ruggiero (SISSA and INFN)

Conformal field theory for inhomogeneous systems: the example of a breathing Tonks-Girardeau gas

Conformal field theory (CFT) has been extremely
successful in describing universal effects in critical one-dimensional
(1D) systems, in situations in which the bulk is uniform. However, in
many experimental contexts, such as quantum gases in trapping
potentials and in several out-of-equilibrium situations, systems are
strongly inhomogeneous. Recently it was shown that the CFT methods can
be extended to deal with such 1D situations: the system's
inhomogeneity gets reabsorbed in the parameters of the theory, such as
the metric, resulting in a CFT in curved space. Here in particular we
make use of CFT in curved spacetime to deal with the
out-of-equilibrium situation generated by a frequency quench in a
Tonks-Girardeau gas in a harmonic trap. We show compatibility with
known exact result and use this new method to compute new quantities,
not explicitly known by means of other methods, such as the dynamical
fermionic propagator and the one particle density matrix at different
times.
Kadanoff Seminar

December 14, 2018
PRC 201 | Friday, 1:30 pm

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Sebastian Huber, Department of Physics, ETH Zürich

Axial Magnetic Fields in Weyl Systems

While acoustic or elastic waves can easily be forced into behaving like electrons on a lattice, it is much harder to find analogies to the physics induced by a magnetic field. In my talk I will show how one can achieve exactly this by using phonons that are described by the relativistic Weyl equation. We engineer an acoustic crystal, where the low energy physics around a chosen frequency resembles the one of a Weyl particle in a magnetic field. We observe the resulting chiral Landau levels and I will present theoretical studies of non-local orbits in the presence of this synthetic magnetic field. Host: Vincenzo Vitelli, 4-8829 or via email to vitelli@uchicago.edu. Persons with a disability who need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The JFI Theory Seminar

December 13, 2018
KPTC 206 | Thursday, 12:15 pm

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Dianne J. Xiao, Stanford University

Hydrocarbons are cheap and abundant feedstocks readily derived from both fossil fuels and emerging renewable resources. Despite their abundance, hydrocarbons have limited applications in chemical synthesis due to the inertness of C–H bonds towards both homolytic and heterolytic bond cleavage. I will share two very different approaches to the selective functionalization of simple hydrocarbons that address these challenges. First, I will highlight a bio-inspired approach to achieve selective alkane hydroxylation using iron-based metal–organic frameworks. The critical influence of both primary and secondary coordination sphere elements on catalyst reactivity, selectivity, and stability will be detailed. Second, I will describe the identification and characterization of a simple heterogeneous base catalyst that converts aromatic hydrocarbons, CO2, and methanol into the corresponding aromatic esters at elevated temperatures. The transformation occurs via a two-step, semi-continuous cycle, and represents the first hydrocarbon CO2 insertion process that does not consume any energy-intensive stoichiometric reagents
Molecular Engineering

December 13, 2018
ERC 201B | Thursday, 10:00 am

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Chiara Daraio, Caltech

Tunable, On-chip Phononic Devices Operating at MHz Frequencies

Nanoelectromechanical systems (NEMS) that operate in the megahertz (MHz) regime allow energy transducibility between different physical domains. For example, they convert optical or electrical signals into mechanical motions and vice versa. This coupling of different physical quantities leads to frequency-tunable NEMS resonators via electromechanical non-linearities. In this talk, I will describe one- and two-dimensional, non-linear, nanoelectromechanical lattices (NEML) with active control of the frequency band dispersion in the radio-frequency domain (10–30 MHz). Our NEMLs consist of a periodic arrangement of mechanically coupled, free-standing nanomembranes with circular clamped boundaries. This design forms a flexural phononic crystal with a wide and well-defined bandgap. The application of a d.c. gate voltage creates voltage-dependent on-site potentials, which can significantly shift the frequency bands of the device. Additionally, I will discuss the experimental realization of topological nanoelectromechanical metamaterials with protected edge states. These on-chip integrated acoustic components could be used in unidirectional waveguides and compact delay lines for high-frequency signal-processing applications.
Computations in Science

December 12, 2018
KPTC 206 | Wednesday, 12:15 pm

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Prof. Sean T. Roberts, Department of Chemistry, University of Texas-Austin

Manipulating Energy and Spin for Photon Up- and Down-conversion

The negligible spin-orbit coupling in many organic molecules creates opportunities to alter the energy of excited electrons by manipulating their spin. In particular, molecules with a large exchange splitting have garnered interest due to their potential to undergo singlet fission (SF), a process where a molecule in a high-energy spin-singlet state shares its energy with a neighbor, placing both in a low-energy spin-triplet state. When incorporated into photovoltaic and photocatalytic systems, SF can offset losses from carrier thermalization, which account for ~50% of the energy dissipated by these technologies. Likewise, compounds that undergo SF’s inverse, triplet fusion (TF), can be paired with infrared absorbers to create structures that upconvert infrared into visible light. In this presentation, I will review our group’s efforts to create organic:inorganic structures that use SF and TF for improved light harvesting and photon upconversion. Host: Andrei Tokmakoff, 4-7696 or via email at tokmakoff@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

December 11, 2018
GCIS W301 | Tuesday, 4:00 pm

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Joaquín Rodríguez-López, University of Illinois at Urbana-Champaign

Elucidating Electrochemical Energy Materials Through Versatile Electrochemistry

In this seminar, I will discuss how new polymeric and low-dimensional materials, as well as an expanded electroanalytical toolbox for understanding interfaces, are allowing us to discover new synergies at the nano and mesoscale for emerging battery technologies. I will describe in detail one system where nano-scale heterogeneity has an impact on macro-scale performance: novel redox active polymers (RAPs) for size-selective flow batteries. Highly soluble RAPs are new players in redox flow technologies, and as part of our collaboration with the Joint Center for Research Energy Storage (JCESR), we are exploring the opportunities that macromolecular design offers for tuning their electrochemical performance. These investigations span across several areas of knowledge, from the interrogation of individual polymer particles, to the elucidation of new redox polyelectrolyte dynamics, and to the evaluation of flow battery performance. Finally, I will describe how we have applied insightful interfacial design and analysis to better understand other energy technologies such as ion batteries and electrocatalysts. Fundamental pursuit of electrode design principles have led us to investigate intercalation processes in low dimensional materials, and the use of ultra-thin electrodes for creating new charge transfer strategies on hetero-structures.
Molecular Engineering

December 11, 2018
ERC 201B | Tuesday, 10:00 am

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C. Rose Kennedy, Princeton University

Leveraging Mechanistic Insight to Enable Catalyst-Controlled Chemo-, Regio- & Stereoselective C–C Bond Formation

Mechanistic elucidation provides potent tools for enabling the design of efficient and selective catalytic transformations. Examples of mechanism-guided method development, drawing from the complementary strengths of ion-pairing organocatalysis and organometallic chemistry to achieve selective C–C bond formation, are described.

In the former case, combined experimental and computational analyses delineating the mechanisms of representative amido-thiourea-catalyzed transformations are discussed. Insights from these studies enabled (i) the rational design of linked bis-thioureas that impart enhanced efficiency for enantioselective anion-abstraction catalysis and (ii) the introduction of a synergistic ion-binding strategy for asymmetric catalysis of transformations involving electronically diffuse transition structures.

In the latter case, iron complexes bearing redox-active ligands are explored as catalysts for hydrovinylation and cycloaddition reactions proceeding through the intermediacy of metallacycles. Mechanistically informed ligand designs are leveraged to control metallacycle formation and fate to upgrade olefinic coupling partners with control of chemo-, regio-, and diastereoselectivity. Applications of the resulting cycloadducts for the synthesis of fuels, polymers, and fine chemicals are discussed.
Chemistry

December 10, 2018
Kent 102 | Monday, 1:15 pm

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Physics with A Bang! Holiday Lecture and JFI Open House

Students, families, teachers and especially the curious are invited to attend our annual Holiday Lecture and Open House. See fast, loud, surprising and beautiful physics demos performed by Profs. Heinrich Jaeger and Sidney Nagel. Talk to scientists about their latest discoveries. Participate in hands-on activities related to their research.

Saturday, December 8th, 2018
Kersten Physics Teaching Center
5720 S. Ellis Ave., Chicago, IL

Lecture repeated at 11am and 2pm
Open House and Demo Alley from 12pm-4pm
Lab Tours in the afternoon

Doors for the Lectures open 30 minutes before each show. Please note: there will be no online registrations, and will be a first to arrive, first ticketed event. We do not guarantee availibility of seating, but shows will also be streamed live to alternate venues. Those needing special assistance, please send an email to ecs@uchicago.edu.
Special JFI Seminar

December 8, 2018
KPTC 106 | Saturday, 11:00 am

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Junichiro Yamaguchi, Waseda University

Making Bonds by Breaking Bonds: An Unconventional Approach to Making Molecules


Chemistry

December 7, 2018
Kent 120 | Friday, 1:15 pm

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Abigail Vieregg, University of Chicago

Discovering the Highest Energy Astrophysical Neutrinos Using a Radio Phased Array

Ultra-high energy neutrino astronomy sits at the boundary between particle physics and astrophysics. The detection of high energy neutrinos is an important step toward understanding the most energetic cosmic accelerators and would enable tests of fundamental physics at energy scales that cannot easily be achieved on Earth. IceCube has detected astrophysical neutrinos at lower energies, but the best limit to date on the flux of ultra-high energy neutrinos comes from the ANITA experiment, a NASA balloon-borne radio telescope designed to detect coherent radio Cherenkov emission from cosmogenic ultra-high energy neutrinos. The future of high energy neutrino detection lies with ground-based radio arrays, which would represent a large leap in sensitivity. I will discuss the demonstrated performance of a new radio phased array design that we have implemented on the ARA experiment at the South Pole and on the new BEACON experiment on White Mountain in California. The radio phased array has improved sensitivity to high energy cosmic particles and will push the energy threshold for radio detection down to overlap with the energy range probed by IceCube.
Physics Colloquium

December 6, 2018
KPTC 106 | Thursday, 4:00 pm

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Katlyn K. Meier, Stanford University

Spectroscopic Characterization of Unique Iron and Copper Active Sites in Biology


Chemistry

December 6, 2018
Kent 120 | Thursday, 12:30 pm

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Diana Qiu, University of California, Berkeley

Excitons in Flatland: Exploring and Manipulating Many-body Effects on the Optical Excitations in Quasi-2D Materials

Since the isolation of graphene in 2004, atomically-thin quasi-two-dimensional (quasi-2D) materials have proven to be an exciting platform for both applications in novel devices and exploring fundamental phenomena arising in low dimensions. This interesting low-dimensional behavior is a consequence of the combined effects of quantum confinement and stronger electron-electron correlations due to reduced screening. In this talk, I will discuss how the low-energy optical excitations (excitons) in quasi-2D materials, such as monolayer transition metal dichalcogenides and few-layer black phosphorus, differ from typical bulk materials. In particular, quasi-2D materials are host to a wide-variety of strongly-bound excitons with unusual excitation spectra and massless dispersion. The presence of these excitons can greatly enhance both linear and nonlinear response compared to bulk materials, making them ideal candidates for applications in optoelectronics, energy harvesting, and energy conversion. Moreover, due to enhanced correlations and environmental sensitivity, the electronic and optical properties of these materials can be easily tuned. I will discuss how substrate engineering, stacking of different layers, and the introduction or removal of defects can be used to tune the band gaps and optical selection rules in quasi-2D materials.
Molecular Engineering

December 6, 2018
ERC 201B | Thursday, 10:00 am

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Lou Charkoudian, Haverford College

Capturing Transient Interactions of Proteins Involved in Natural Product Biosynthesis

How do microorganisms produce chemically diverse and structurally complex molecules? How can humans harness this technology to better human health and the environment? These questions inspire our lab to study acyl carrier proteins (ACPs), which serve as central hubs in polyketide and fatty acid biosynthetic pathways. ACPs are notoriously challenging to study because the fast motions of the ACP phosphopantetheine (Ppant) arm make its conformational dynamics difficult to capture using traditional spectroscopic approaches. In this talk, I will present how the synthetic modification of the terminal thiol of the ACP Ppant arm can transform the ACP reactive site into a vibrational spectroscopic probe that can report on mechanistically-relevant movements of the ACP. I will share stories about how we leverage Ppant probes to resolve conformational dynamics on the picosecond time scale and visualize ACP complex formation with functional catalytic partners. We anticipate that these methods will be valuable in future structural and biosynthetic engineering studies because our approach is generalizable, practical, and scalable. Our studies combine concepts and techniques spanning biochemistry, organic chemistry, bioinformatics, and physical chemistry, and therefore I hope this talk will be of interest to a broad audience.
Chemistry

December 5, 2018
GCIS W301 | Wednesday, 1:00 pm

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David Lubensky, University of Michigan

Organ size, inflationary embryology, and the statistical physics of tissue growth

One of the enduring mysteries of biology is how organs know to stop growing at the correct size and how those sizes are coordinated so that the animal retains the correct proportions. Here, we discuss several studies that in different ways address the precision with which organ size can be controlled. We first show that there are severe limits to the coordination of the sizes of left and right organs (like the left and right wings of a fruit fly) by chemical signals, suggesting that organ size is set primarily autonomously. We then consider the noisy dynamics of the growth of individuals tissues in the presence of various feedback laws. We find that only certain forms of mechanical feedback can specify a unique organ size. We also show that, even in the simplest, homogeneous case, stochastic growth of an elastic tissue has unexpectedly rich behavior: For example, it exhibits power law correlation functions, reminiscent of those seen in cosmological models, and soft modes that allow for diffusive growth of labelled clones of cells.
Computations in Science

December 5, 2018
KPTC 206 | Wednesday, 12:15 pm

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Weixin Tang, Harvard University

From Peptide Antibiotics to CRISPR-mediated Synthetic Memories: Tools from the Microbial Arsenal


Chemistry

December 5, 2018
GCIS W301 | Wednesday, 11:00 am

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Prof. Christophe Delerue, IEMN- CNRS, Paris

Localized Surface Plasmon Resonance in Doped Semiconductor Nanocrystals

Nanocrystals of heavily-doped semiconductors have recently emerged as very promising materials for plasmonics. In contrast to nanocrystals of noble metals, their Localized Surface Plasmon Resonance (LSPR) can be easily tuned in energy by controlling the carrier concentration through doping. In addition, due to the low concentration of carriers compared to metals, the LSPR can be
extended to infrared and near-infrared ranges. Recent experimental studies have demonstrated the existence of LSPR in doped nanocrystals of Si and different types of oxides (ZnO, SnO2, In2O3). However, the physics of the LSPR in these nanocrystals is not totally understood. In the first part of my talk, I will give of general overview of the field of doped semiconductor nanocrystal
plasmonics. In the second part, I will review theoretical studies that we have performed in order to address fundamental issues which are still highly debated. The evolution with doping concentration of the optical processes from single-electron to many-electron transitions will be described. The conditions required for the emergence of collective modes will be discussed. The results of atomistic calculations will be compared with those of more classical approaches. The role of the quantum confinement and the influence of the dopant potential and location will be discussed. The intrinsic mechanisms at the origin of plasmon damping in doped nanocrystals will be analyzed. The results confirm that doped nanocrystals are very promising for the development of IR plasmonics.Host: Philippe Guyot-Sionnest,2-7161 or via email at pgs@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The 1st Tuesday JFI Colloquium

December 4, 2018
GCIS W301 | Tuesday, 4:00 pm

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Srimoyee Sen, University of Washington

Anyonic particle-vortex statistics and the nature of dense QCD

I discuss the recent theoretical observation of Z_3 -valued particle-vortex braiding phases in high density QCD and its implications for higgs-confinement complementarity. As a consequence of the braiding phases, certain mesonic and baryonic excitations, in the presence of a superfluid vortex, have orbital angular momentum quantized in units of 1/3. Such non-local topological features can distinguish phases whose realizations of global symmetries, as probed by local order parameters, are identical. If Z_3 braiding phases and angular momentum fractionalization are absent in lower density hadronic matter, as is widely expected, then the quark matter and hadronic matter regimes of dense QCD must be separated by at least one phase transition
Kadanoff Seminar

December 4, 2018
PRC 201 | Tuesday, 1:30 pm

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Mark Levin, Harvard University

Catalytic Manipulation of Reactivity and Selectivity at High-Valent Nuclei

This presentation will examine aspects of reactivity and selectivity discovered through the exploration of the chemistry of high-valent nuclei [Au(III), Pt(IV), and I(III)]. The first part concerns two examples wherein transition metals are examined as substrates for catalytic reactions rather than in their traditional role as catalysts. Operating from this perspective, supramolecular catalysis of C(sp3)-C(sp3) reductive elimination and organoborane catalyzed C(sp3)-CF3 reductive elimination will be discussed, with the latter applied to [18F]-radiotrifluoromethylation. The second section will continue the focus on fluorination through the development of a new aryliodine catalyst for enantioselective olefin difluorination, exploring structural features that improve catalyst robustness and selectivity and enabling the preparation of chiral fluorinated building blocks.
Chemistry

December 3, 2018
Kent 120 | Monday, 1:15 pm

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Brad P. Carrow, Princeton University

Leveraging Polarizability and Electrophilicity in Catalysts for Challenging Coupling Reactions

A general approach by our group for the development of new catalytic synthetic methods that occur with higher efficiency and selectivity, use simpler reagents, and proceed with lower energy demand involves new ancillary ligand design coupled with fundamental studies of how metal-ligand bonding dictates catalytic reactivity. In this context, the presentation will focus on our recent efforts to discover new phosphorus- and sulfur-based ligands and associated metal catalysts that manifest special properties from seemingly "weak" interactions, for instance London dispersion. Two case studies will be discussed that exemplify such effects and emphasize many lessons yet to be learned about how structure controls reactivity in synthetic catalysts. In one case, a new transmetalation mechanism can be triggered in reactions of low-coordinate Pd complexes possessing polarizable diamondoid substituents, which enables smooth coupling catalysis even with historically unstable organoboron reagents. Studies of oxidative dehydrogenative coupling reactions will also showcase evidence for a C−H bond activation mechanism, termed electrophilic CMD or "eCMD", which has characteristics distinct from established SEAr and concerted metalation-deprotonation (CMD) pathways for C−H functionalization. Transition state analyses suggest this reaction pathway could be a general class of C−H activation manifested by many other transition metal catalysts, and selection rules have been identified for predicting what catalyst structures manifest either classic CMD or eCMD, which occur with unique substrate preferences and selectivity.
Chemistry

November 30, 2018
Kent 120 | Friday, 1:15 pm

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Junqi Li, Yale University

From Automated Small Molecule Synthesis to Understanding Chiral Phosporic Acid Catalysis

Efforts to discover and optimize new small molecule function are often impeded by limitations in synthetic access to small molecules. This is because small molecule syntheses typically employ strategies and purification methods that are highly customized for each target. Furthermore, the molecular interactions between the catalyst and substrate are often not understood in catalyst-controlled selective reactions, thus impeding the design of new and more selective catalysts. In this seminar, an iterative cross-coupling strategy that enables the systematized and automated synthesis of different types of small molecules will be presented. The second part of the talk will discuss enantio- and site-selective reactions catalyzed by chiral phosphoric acids with a focus on understanding key catalyst-substrate interactions.
Chemistry

November 29, 2018
Kent 120 | Thursday, 1:15 pm

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Andrei Parnachev

Regge limit in Holographic Conformal Field Theories

We will discuss the Regge limit of correlators in holographic CFTs and its
physical implications. Examples include constraints on the three-point couplings of the stress tensor
and the relation between heavy states in CFT and black holes in dual gravity.
Theory Seminar

November 28, 2018
PRC 201 | Wednesday, 1:30 pm

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Felice Frankel

More Than Pretty Pictures

Graphics, images and figures — visual representations of scientific data and concepts — are critical components of science and engineering research. They communicate in ways that words cannot. They can clarify or strengthen an argument and spur interest into the research process.

But it is important to remember that a visual representation of a scientific concept or data is a re-presentation and not the thing itself –– some interpretation or translation is always involved. Just as writing a journal article, one must carefully plan what to “say,” and in what order to “say it.” The process of making a visual representation requires you to clarify your thinking and improve your ability to communicate with others.

In this talk, I will show my own approach to creating depictions in science and engineering—the successes and failures. Included will be a discussion about how far can we go when “enhancing” science images.
Computations in Science

November 28, 2018
KPTC 206 | Wednesday, 12:15 pm

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Wheland Lecture: Professor Jack W. Szostak, Harvard University

The Surprising Chemistry of Nonenzymatic RNA Replication

The RNA genomes of the first cells are thought to have emerged from the nonenzymatic replication of short RNA strands. We have recently found that the template-directed reaction of a primer with activated nucleotide substrates proceeds through an unexpected covalent intermediate. Our kinetic and crystallographic studies have provided insight into the mechanism of this key reaction, and to improvements in RNA copying chemistry that are both more prebiotically plausible and more accurate, efficient, and general.
Chemistry

November 28, 2018
GCIS W301 | Wednesday, 12:00 pm

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Prof. Zahra Fakhraai, Department of Chemistry, University of Pennsylvania

Understanding Glass Transition Through Interfacial Properties

Free surfaces and interfaces can affect properties of glassy systems over length scales that can be much longer than the intermolecular interaction potential. A fundamental understanding of the magnitude and length scale of these effects can allow us to understand the glass transition phenomenon and engineer nano-scaled materials with unique properties. In this presentation I show two examples of such effects and their use in producing thermally and kinetically stable glass materials. Extensive research in the past two decades has shown that the free surface of glasses, in particular for polymeric and organic glasses, have dramatically faster dynamics, resulting in strong reduction in their glass transition temperature, Tg, in ultra-thin films. We have recently shown that the surface dynamics can be faster by as much as eight orders of magnitude resulting in an apparent glass to liquid transition in molecular glass films as thick as 30 nm. The details of the thickness-dependent relaxation dynamics in thin films can elucidate properties of bulk glass that are key in verifying glass transition models. The enhanced mobility over such a large length scale can also help produce stable glasses with unique molecular packing upon physical vapor deposition.

In another example, we demonstrated that polymers’ thermal stability can be significantly improved in highly confined geometries. Capillary rise infiltration (CaRI) is used to load randomly closed-packed films of nanoparticles with various polymers. By changing the NP diameter, polymer can be confined in length scales as small as 2-3 nm. Under these conditions, entropic and enthalpic effects induced by interfaces play the dominant role in stabilizing the polymer, leading to higher Tg, higher viscosity, and improved resistance to burning and thermal degradation. We discuss the role of various parameters in achieving these thermally stable states. Host: Julia Murphy, jgmurphy102@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

November 27, 2018
GCIS W301 | Tuesday, 4:00 pm

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Yichen Hu, University of Pennsylvania

On the Brink of Fractionalization

Systems of strongly interacting particles can give rise to topological phases beyond non-interacting limit. Although unique features of strongly interacting topological phases, such as fractionalization of quantum degrees of freedom, have important applications in quantum information processing, these topological phases are still far from experimental realizations. In this talk, by presenting constructions of two strongly interacting topological phases, I will argue the key mechanism of their realizations is to add interactions near topological phase transitions. I will first introduce a model of interacting Majorana fermions that describes a superconducting phase with Fibonacci topological order. Then I will show that a correlated fluid of electrons and holes, dubbed fractional excitonic insulator phase, can exhibit a fractional quantum Hall effect at zero magnetic field. I will present physical evidence and conjecture that this phase can be realized in a higher angular momentum excitonic paired system in the presence of interactions.
Kadanoff Seminar

November 27, 2018
PRC 201 | Tuesday, 1:30 pm

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Ethan Garner, PhD, Molecular and Cellular Biology, Center for Systems Biology, Harvard

Quantitating the motions of filaments gives insight into how bacteria grow as rods & control their rate of growth

Prof. Garner is hosted by Ed Munro and Sean Crosson
Biophysical Dynamics

November 27, 2018
GCIS W301 | Tuesday, 12:00 pm

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Wheland Lecture: Professor Jack W. Szostak, Harvard University

The Origin of Cellular Life

To understand the origin of life on Earth, and to evaluate the potential for life on exoplanets, we must understand the pathways that lead from chemistry to biology. Recent experiments suggest that a chemically rich environment that provides the building blocks of membranes, nucleic acids and peptides, along with sources of chemical energy, could result in the emergence of replicating, evolving cells. I will discuss physical mechanisms that enable the growth and division of model protocells, the possible nature of primordial RNA, and the chemistry of its replication.
Chemistry

November 26, 2018
Kent 120 | Monday, 4:00 pm

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Emily Sprague-Klein, Northwestern University

Hot Electrons & Transient Molecular Dynamics in Plasmonic Nanomaterials

Excitation of localized surface plasmon resonances yield non-equilibrium carrier populations that can then be harnessed to drive site-specific chemical processes at the nanoscale. We demonstrate the first direct detection of the molecular anion radical generated from plasmon-driven electron transfer in tightly confined sub-nanometer gaps under intense visible light irradiation. The energetics of these transient hot electron chemical processes are catalogued in a range of polypyridyl complexes in corroboration with open-shell density functional theory. Techniques for the observation of molecule-surface structural dynamics with high temporal and spatial resolution are discussed. The findings have broad applicability towards designing organic-inorganic hybrid microelectronics and nanoscale chemical reactors for surface redox reactions on the subnanometer scale. Host: Sarah King, 4-3809 or via email to sbking@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI Special Seminar

November 26, 2018
GCIS W301 | Monday, 1:30 pm

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Tania Baker, Department of Biology, Massachusetts Institute of Technology


Biophysical Dynamics

November 21, 2018
GCIS W301 | Wednesday, 1:00 pm

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Gabriel Won

Glueing together Modular flows with free fermions

e revisit the calculation of multi-interval modular Hamiltonians for free fermions using a Euclidean path integral approach. We show how the multi-interval modular flow is obtained by glueing together the single interval modular flows. Our methods are based on a derivation of the non-local field theory describing the reduced density matrix, and makes manifest it's non-local conformal symmetry and $U(1)$ Kacs-Moody symmetry. We will show how the non local conformal symmetry provides a simple calculation of the entanglement entropy.
Kadanoff Seminar

November 20, 2018
PRC 201 | Tuesday, 1:30 pm

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Gregory R. Bowman, PhD, Washington University

Identifying & Exploiting Protein Shape-shifting

A protein is a dynamic shape-shifter whose function is determined by the set of different structures it adopts. Unfortunately, it is often impossible to experimentally characterize most of these structures with the atomic resolution one would like in order to gain mechanistic insight or design drugs and mutations. The Bowman lab is combining enhanced sampling methods, such as Markov state models (MSMs), with biophysical experiments to overcome this limitation. Using this integrative approach, we are coming to a better understanding of how allosteric signals are transmitted between distant parts of a protein. We are also uncovering cryptic pockets that are absent in available experimental structures and provide new targets for drug development. To test our insights, we are designing and experimentally characterizing small molecules and mutations that exert allosteric control over distant functional sites. Examples of ongoing projects include (1) understanding how mutations give rise to antibiotic resistance, (2) designing allosteric drugs to combat antibiotic resistant infections, (3) understanding allosteric networks in G proteins and designing allosteric anti-cancer drugs, and (4) understanding and interfering with the mechanisms of Ebola infection.
Biophysical Dynamics

November 20, 2018
GCIS W301 | Tuesday, 12:00 pm

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Professor Matthew Bogyo, Stanford University

Chemical Tools for Identification and Imaging of Hydrolases Involved in the Pathogenesis of Cancer and Infectious Disease

Hydrolases are enzymes that often play pathogenic roles in many common human diseases such as cancer, asthma, arthritis, atherosclerosis and infection by pathogens. Therefore, tools that can be used to dynamically monitor their activity can be used as diagnostic agents, as imaging contrast agents and for the identification of novel enzymes and drug leads. In this presentation, I will describe our efforts to design and synthesize small molecule probes that produce a fluorescent signal upon binding to a hydrolase target. In the first part of the presentation, I will discuss probes targeting the cysteine cathepsins and their application to real-time fluorescence guided tumor resection and other diagnostic imaging applications. In the second half of the presentation, I will present our efforts to identify novel hydrolases in the pathogenic bacteria Staphylococcus aureus that could be targeted to enable both treatment and non-invasive imaging of disease progression.
Chemistry

November 19, 2018
Kent 120 | Monday, 4:00 pm

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Professor Oren Petel, Department of Mechanical and Aerospace, Engineering Carleton University

Impact Injury Evaluation and Mitigation Strategies Using X-ray Imaging

Brain trauma from impact and/or blast and the resulting neurodegeneration has been linked to devastating health outcomes. While the use of helmets by athletes or soldiers can serve to drastically reduced the incidence of severe focal brain injuries, there continues to be a concerning level of incidence. While acute exposure to an injurious event can be detrimental to head health, there is building evidence suggesting that repeated low‐level exposure events are similarly of concern. Current helmet testing standards for impact events focus on the rigid‐body kinematics of head motion in the hope that they can be correlated to metrics of importance in leading injury mechanisms. These approaches typically use state‐of‐the‐art computational models that attempt to link these kinematic measures back to tissue strains and deformation profiles. Despite model validation against the same sets of cadaveric impact data, models predict vastly different strain profiles within tissue. In this presentation, I will provide an overview of our broad injury biomechanics research program at Carleton. This research program makes use of a state‐of‐the‐art X‐ray facility, designed by my research group, to achieve continuous X‐ray imaging speeds of 10,000 fps to investigate the dynamic response of cadaveric specimens, head models, and ex vivo tissue specimens as well as models for understanding impact mitigation using cellular materials and design strategies. Host: Heinrich Jaeger, 2-6074 or via email at h-jaeger@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI Special Seminar

November 19, 2018
GCIS E223 | Monday, 1:30 pm

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Alex Turzillo, Caltech

Free and Interacting Short-Range Entangled Phases of Fermions: Beyond the Ten-Fold Way

It is well-known that sufficiently strong interactions can destabilize some SPT phases of free fermions, while others remain stable even in the presence of interactions. It is also known that certain interacting phases cannot be realized by free fermions. In this talk, we will study both of these phenomena in low dimensions and determine the map from free to interacting SPT phases for an arbitrary unitary symmetry. We will also describe how to compute invariants characterizing interacting phases for free band Hamiltonians with symmetry (in any dimension) using only representation theory.
Kadanoff Seminar

November 16, 2018
PRC 364 | Friday, 1:30 pm

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Closs Lecture: Professor Lewis Rothberg, University of Rochester

What You Don't See Can Hurt You: The Dark Matter Problem in Luminescent Conjugated Polymers

High luminescence yields in solution bode well for easily processed conjugated polymers as the emissive species in photopumped film lasers, biological tags and display technology. The luminescence efficiency in the solid state, however, is often found to be low even when the polymer is doped dilutely into inert hosts. Our recent research involves trying to systematically vary morphology at the single chain level to illustrate the interplay between energy transfer amongst chromophores and aggregation of chromophores in determining the photophysics. We find dramatic variations in behavior as the polymer morphology evolves from extended to collapsed. In the intermediate case, we observe surprising and instructive phenomena that cannot be explained in the context of previous literature models. For example, we show that it is possible to greatly increase photoluminescence by deliberate selective photooxidation of low energy but poorly emitting chromophores. Consequences of this finding include intense luminescence spikes in single chain spectroscopy and the ability to post-process some bulk polymer samples to improve their luminescence efficiency. A revised model of the photophysics accounts for these phenomena and explains the failure of luminescence to scale with molecular weight, an observation fondly labeled “the dark matter problem” by Ivan Scheblykin.
Chemistry

November 16, 2018
Kent 120 | Friday, 1:15 pm

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Prof. Frederico Toschi, The Department of Applied Physics, Eindhoven University of Technology (ATU/e)

Genetic Competition in Weakly Compressible Turbulent Flows

The genetic competition for biological species living in marine environments can be severely influenced by fluid advection. Very often, in oceans and in lakes, cell generation times are precisely in the inertial range of eddy turnover times and therefore the influence of turbulence must be properly taken into account. We employ both an off-lattice agent-based simulation as well as an on-site density-based model to describe two competing populations in one and in two spatial dimensions under the influence of advecting (turbulent) velocity fields. The novel on-site density-based model allows to accurately and efficiently describe the dynamics of the population and the genetics of large number of individuals, making this the ideal tool to study populations in two dimensions. We find that the presence of compressible turbulent velocity fields can have a very strong effect on genetic competitions. In particular, even in regimes where the overall population structure is approximately unaltered, the flow can significantly diminish the effect of a selective advantage on fixation probabilities. We explain this effect in terms of the enhanced survival of organisms born at the sources in the flow and the influence of Fisher genetic waves. We find for both cases that even in a regime where the overall population structure is approximately unaltered, the flow can significantly diminish the effect of a selective advantage on fixation probabilities. We understand this effect in terms of the enhanced survival of organisms born at sources in the flow and of the influence of Fisher genetic waves. Host: Vincenzo Vitelli, 2-7206 or via email at vitelli@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
JFI / IME Seminar

November 16, 2018
GCIS E123 | Friday, 12:15 pm

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Giorgio Gratta, Stanford University

Measuring gravity at short distances and other fun tricks with levitated microspheres


Physics Colloquium

November 15, 2018
KPTC 106 | Thursday, 4:00 pm

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Chen-Te Ma, National Taiwan University

Bell’s Inequality, Generalized Concurrence and Quantum Entanglement

We demonstrate an alternative evaluation of quantum entanglement by measuring maximum violation of Bell's inequality without performing a partial trace operation in an n-qubit system by bridging maximum violation of Bell's inequality and a generalized concurrence of a pure state. This proposal is realized when one subsystem only contains one qubit and a quantum state is a linear combination of two product states. Finally, a relation of the generalized concurrence of a pure state and the maximum violation of Bell's inequality is also demonstrated in a 2n-qubit state.
Kadanoff Seminar

November 15, 2018
PRC 201 | Thursday, 2:00 pm

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Tony Gherghetta

Naturalizing SUSY with the Relaxion and the Inflaton


Theory Seminar

November 14, 2018
PRC 201 | Wednesday, 1:30 pm

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Oni Basu, University of Chicago

Single-cell Transcriptomics and Biology using Microfluidics

The basic units of biological structure and function are cells, which exhibit wide variation in regard to both type and state. We assess such variation by simultaneously profiling the transcriptomes of thousands of single mammalian cells (Drop-seq) or nuclei (DroNc-seq), using high-throughput emulsion microfluidics and DNA barcodes. These are accomplished by (a) encapsulating and lysing one cell/nuclei per emulsion droplet, and (b) barcoding RNA contents from each cell/nuclei using unique DNA-barcoded micro-beads, (c) performing Next-Gen Sequencing.

We are using these droplet-based techniques to profile cell types comprising complex tissues in a variety of tissue-types such as the heart and solid tumors in mouse models and human primary tissue. Besides, we are using Drop-seq and DroNc-seq to profile cell-states, particularly cellular heterogeneity in development and differentiation processes using a combination of cell lines, mouse embryonic tissue, in vitro culture, and human induced pluripotent stem cells.

We also develop custom microfluidic devices to study phenotypic responses of cells to different environmental stimuli including physical, bio-chemical and pathogenic stimuli; I will provide some examples to illustrate some applications.
Computations in Science

November 14, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - Prof. Aashish Clerk, IME, The University of Chicago

Driven-dissipative Quantum Phenomena: from Synthetic Non-reciprocity to New Kinds of Topology

In this talk, I’ll give an introduction to theory work in my group focused on understanding and exploiting driven-dissipative quantum phenomena in engineered quantum systems. I’ll start by discussing work showing how engineered dissipation can make almost any kind of interaction between two subsystems non-reciprocal (i.e. uni-direcitonal). This is provides a systematic approach for designing quantum systems with one-way interactions, with applications ranging from new kinds of quantum measurement devices to unusual many-body effects. In the second part of the talk, I’ll focus on work exploring how two-photon (parametric) driving can be used to realize new kinds of topological bosonic systems. While these systems have Hamiltonians analogous to topological superconductors, their physics is remarkably distinct from their fermionic partners. Among other things, I’ll discuss the surprising properties of a bosonic version of the Kitaev-Majorana chain, and how these ideas could be realized with superconducting quantum circuits. Host: Timothy Berkelbach, 4-9879 or via email at berkelbach@uchicago. Persons with a disability who may need assistance please contact Brenda Thomas 2-7156 or by email to bthomas@uchicago.edu.
The Tuesday JFI Seminar

November 13, 2018
GCIS W301 | Tuesday, 4:00 pm

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Hart Goldman, Illinois

Dirac Composite Fermions and Emergent Reflection Symmetry about Even Denominator Filling Fractions

Motivated by the appearance of a “reflection symmetry” in transport experiments and the absence of statistical periodicity in relativistic quantum field theories, we propose a series of relativistic composite fermion theories for the compressible states appearing at filling fractions 1/2n in quantum Hall systems. These theories consist of electrically neutral Dirac fermions attached to 2n flux quanta via an emergent Chern-Simons gauge field. While not possessing an explicit particle-hole symmetry, these theories reproduce the known Jain sequence states proximate to filling 1/2n, and we show that such states can be related by the observed reflection symmetry, at least at mean field level. We further argue that the lowest Landau level limit requires that the Dirac fermions be tuned to criticality, whether or not this symmetry extends to the compressible states themselves
Kadanoff Seminar

November 13, 2018
PRC 201 | Tuesday, 1:30 pm

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Zhen Gu, PhD, UCLA

Leverage Physiology for Bioresponsive Drug Delivery

Spurred by recent advances in materials chemistry, molecular pharmaceutics & nanobiotechnology, stimuli-responsive “smart” systems offer opportunities for precisely delivering drugs in dose-, spatial- & temporal-controlled manners. In this talk, I will discuss our ongoing efforts in developing physiological signal-triggered bio-responsive drug delivery systems. I will first present the glucose-responsive synthetic systems for biomimetic delivery of insulin for diabetes treatment. Bio-responsive microneedle patches and vesicle fusion-mediated synthetic beta cells will be emphasized.
I will further discuss the local & targeted delivery of immunomodulatory therapeutics for enhanced cancer therapy. Our latest study utilizing platelets and injectable gels for targeted/local delivery of immune checkpoint inhibitors will be specifically introduced.
Biophysical Dynamics

November 13, 2018
GCIS W301 | Tuesday, 12:00 pm

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Mulliken Lecture: Professor Peter Rossky, Rice University

Translating the Message in Spectroscopic Probes of Conjugated Molecular Materials

Over recent decades, there have been a steadily increasing number of studies on electronically conjugated materials for use in solar photovoltaic cells, organic transistors, and fluorescent probes. Progress in using semiconducting polymers has been limited by a fundamental lack of knowledge at the nanoscale underlying variations in electro-optical behavior. Hence, in contrast to familiar silicon-based technology, there is a dearth of principles to drive the bottom-up design of material building blocks.
Experiments probe such materials by their response to light, i.e., spectroscopically. The challenge is to interpret the observations in molecular terms. Computational modeling based on the physics of atomistic details and explicit electronic structure is ideally suited to enabling this connection of spectra to structure, since the connection in modeling is unambiguous while the experiment provides a strong constraint on the validity of the model. In this presentation, I will discuss examples of conjugated molecular material systems studied by theoretical, modeling, and experimental approaches that elucidate both atomistic and electronic structure and dynamics in a way inaccessible to either theory or experiment alone. Examples from the area of conjugated polymers and also from biosensors based on GFP will be presented.
Chemistry

November 12, 2018
Kent 120 | Monday, 4:00 pm

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Professor David Sarlah, University of Illinois at Urbana-Champaign

Dearomative Functionalization Strategies and Synthesis of Anticancer Natural Products"

Small complex molecules are highly desired in all areas of chemistry, but they are also often difficult to access. Selective transformations of aromatic compounds could provide a more direct route to such desirable targets; however, the many challenges associated with dearomative functionalization have left these types of reactions widely underdeveloped. Our group has been developing new strategies that bridge the gap between dearomatization functionalization and alkene chemistry. In pursuit of this goal, we have developed dearomative functionalizations using small molecules – arenophiles – that enable reactions of isolated alkenes in aromatic substrates. Thus, well-established olefin reactions, such as dihydroxylation and reduction, can now be more directly applied to arenes. Additionally, arenophiles in combination with transition metal catalysis provide unique platform and enable the rapid access to a diverse range of products that are both challenging to synthesize via existing methods and complementary to those acquired through biological or chemical dearomative processes. Finally, using this methodology we have recently completed the synthesis of several complex anticancer natural products.
Chemistry

November 9, 2018
Kent 120 | Friday, 1:15 pm

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Transient driving that kinetically converts a foe into a friend

body food 12:00
brain food 12:15
MRSEC Baglunch

November 9, 2018
GCIS E123 | Friday, 12:00 pm

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Helen Quinn, SLAC

Science, Engineering and Art as well –why it is hard to teach science well

will reflect on what we know about teaching science for k-12 students and for undergraduates, how we know it, and what it tells us about good teaching. To teach well you must engineer the right learning conditions with careful design goals for what is to be learned, you must understand both the subject area you wish to teach and something of what research on learning tells us about critical aspects of learning that area (this is known as pedagogical content knowledge or content knowledge for teaching) and then you must be a skilled improvisational performance artist to pull off the lessons as intended, responding to the needs of students who enter your classroom with a wide range of prior knowledge, engaging them all as active participants in the learning.

This talk is based on work I have been doing in the area of science education since my retirement in 2010 from physics research, summarizing what I have learned in the process. Illinois and approximately 30 other states have adopted new science standards based on the NAS study “A Framework for k-12 science education” that I led. This study tried to capture the learning about learning from science education research as well as to shift the goals for what needs to be learned. I will discuss how it, together with research studies focused on teaching physics or other sciences at the undergraduate level, suggests changes in undergraduate teaching approaches as well.
Physics Colloquium

November 8, 2018
KPTC 106 | Thursday, 4:00 pm

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IME Distinguished Colloquium Series - Shanhui Fan, Stanford

Concepts of Nanophotonics and Energy Applications

Light, or electromagnetic waves, represent one of the most important carriers of heat and energy. New capabilities to manipulate light, as enabled by new classes of electromagnetic structures such as photonic crystals, metamaterials and plasmonic systems, therefore have significant implications for energy applications. In this talk, we will discuss some of these implications, illustrated by examples of our own recent works ranging from radiative cooling to dynamic wireless power transfer.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

November 7, 2018
KCBD 1103 | Wednesday, 4:00 pm

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Brad Marston, Brown University

Topological Origin of Equatorial Waves

Topology sheds new light on the emergence of unidirectional edge waves in a variety of physical systems, from condensed matter to artificial lattices. Waves observed in geophysical flows are also robust to perturbations, which suggests a role for topology. We show a topological origin for two celebrated equatorially trapped waves known as Kelvin and Yanai modes, due to the Earth’s rotation that breaks time-reversal symmetry. The non-trivial structure of the bulk Poincaré wave modes encoded through the first Chern number of value 2 guarantees existence for these waves. The invariant demonstrates that ocean and atmospheric waves share fundamental properties with topological insulators, and that topology plays an unexpected role in the Earth climate system.
Computations in Science

November 7, 2018
KPTC 206 | Wednesday, 12:15 pm

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1st Tuesday Colloquium - Prof. Mark D. Ediger, University of Wisconsin-Madison

Exploring the Limits of Amorphous Packing with Ultrastable Glasses

Glasses formed by cooling a liquid inherit both their structure and their limited stability from the liquid state. In contrast, glasses prepared by vapor deposition can avoid both of these limitations. By utilizing the high mobility present near the free surface of many organic glasses, vapor deposition can build glasses with low enthalpy, high density, and high thermal stability. Based upon their position on the potential energy landscape, these materials approach “ideal glass” packing that otherwise could only be achieved by annealing a liquid-cooled glass for thousands or millions of years. Vapor deposition of organic semiconductors produces glasses with improved properties for organic electronics, including the ability to produce anisotropic glasses with a wide range of structures. Remarkably, this “anti-epitaxy” process uses the free surface structure as its template, rather than the substrate structure. Recent work has shown that optimizing vapor deposition can produce organic light emitting diodes (OLEDs) that are more efficient and have extended lifetimes. Host: Thomas Witten, 2-2-0948 or via email to t-witten@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The 1st Tuesday JFI Colloquium

November 6, 2018
GCIS W301 | Tuesday, 4:00 pm

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Andy LiWang, PhD, Quantitative and Systems Biol, UC Merced

Can proteins tell time?

Circadian clocks arose in organisms as an adaptation to the rotation of the earth. These clocks produce involuntary anticipation of sunrise and sunset by generating a succession of biochemical phases. In this talk, the mechanism of a model system, that of cyanobacteria, will be described. Briefly, it depends on phosphorylation, long-range allostery, dynamics, and protein metamorphosis. Because a simple mixture of clock proteins and ATP generate a persistent macroscopic rhythm, the mechanism of the clock can be studied in real time as it ticks. Now, signal transduction pathways have been reconstituted with the oscillator so that rhythmic transmission of clock signals can be studied in vitro.
Biophysical Dynamics

November 6, 2018
GCIS W301 | Tuesday, 12:00 pm

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Luca Delacretaz, Stanford University

Bounds on transport and thermalization from positivity


Kadanoff Seminar

November 6, 2018
PRC 215 | Tuesday, 12:00 pm

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Professor Daniel G. Nocera, Harvard University

Food and Fuel from Sunlight, Air and Water


Chemistry

November 5, 2018
Kent 120 | Monday, 4:00 pm

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Naama Barkai, PhD, Molec Genetics and Physics, Weizmann

Robustness & scaling in embryonic development

Naama Barkai, PhD, Departments of Molecular Genetics and of Physics of Complex Systems, Weizmann Institute of Science is the 2018-19 Frederick Seitz Lecturer in Interdisciplinary Science.

Informal reception will follow Dr. Barkai's presentation in the lobby of the KCBD
Biophysical Dynamics

November 5, 2018
KCBD 1103 | Monday, 1:30 pm

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Professor Peter G. Wolynes, Rice University

Energy Landscape Theory: From Folding Proteins to Folding Chromosomes

The statistical mechanics of energy landscapes has resolved the paradoxes of how information-bearing matter can assemble itself spontaneously. I will explain how our current understanding of protein folding landscapes not only leads to successful schemes for predicting protein structure from sequence but also has given quantitative insight into how folding and function shape molecular evolution. While protein folding is, in the main, thermodynamically controlled and not kinetically limited, longer structures in the cell can assemble in a kinetically controlled, nonequilibrium fashion. Nevertheless, I will show how energy landscape theory provides tools for extracting from low resolution experimental structural methods and kinetic information about the structure and cooperative dynamics of chromosomes.'
Chemistry

November 2, 2018
Kent 120 | Friday, 1:15 pm

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Transient driving that kinetically converts a foe into a friend

Eat 12:00
Action 12:15
MRSEC Baglunch

November 2, 2018
GCIS E123 | Friday, 12:00 pm

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Marcos Santander, The University of Alabama

Exploring the high-energy sky with neutrinos and gamma rays

In 2013 the IceCube neutrino observatory, a cubic-kilometer particle detector deployed deep within the South Pole glacier, announced the first detection of an astrophysical flux of high-energy neutrinos in the TeV-PeV range. This breakthrough discovery has prompted a wide-ranging observational effort aimed at identifying the sources of the neutrino flux by combining IceCube measurements with observations spanning the entire electromagnetic spectrum. Gamma rays in particular provide a powerful tool to search for neutrino source counterparts as both particles are produced in high-energy hadronic interactions. The detection and study of neutrino sources would not only signify the start of a new form of astronomy, but could also solve long-standing questions in high-energy astrophysics such as the origin of high-energy cosmic rays. This talk will introduce the IceCube detector, summarize recent results from multi-messenger searches of neutrino sources and present an overview of current and future gamma-ray follow-up observations, especially with the Cherenkov Telescope Array, a ground-based facility for very-high-energy gamma-ray astronomy currently under construction.
Physics Colloquium

November 1, 2018
KPTC 106 | Thursday, 4:00 pm

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Saebyeok Jeong, Stony Brook

Opers, surface defects, and Yang-Yang functional

In this talk, I will introduce a gauge theoretical derivation of a correspondence which relates quantization of integrable system to symplectic geometry [1]. First, I will briefly review how the Hitchin integrable systems are associated with the class S theories. The Hitchin moduli space is identified with the moduli space of flat connecitons, with a distinctive Lagrangian submanifold of opers. It is suggested that the holomorphic functions on the space of opers are the (off-shell) spectra of the quantum Hitchin Hamiltonians [2]. Moreover, the conjecture in [4] states that the generating function for the space of opers is equal to the effective twisted superpotential of the class S theory on the two-dimensional omega-background. I will show a gauge theoretical derivation of the correspondence. The derivation involves the following key ingredients:
1) Use half-BPS codimension-two (surface) defects in the class S theories to construct the opers and their solutions.
2) Analytically continue the surface defects partition functions to build connection formulas of the solutions.
3) Construct a Darboux coordinate system relevant to the correspondence.
4) Compute the monodromies of opers from 2) and compare with the expressions from 3) The direct comparison establishes the desired identity.
Theory Seminar

October 31, 2018
PRC 201 | Wednesday, 1:30 pm

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Timothy C. Berkelbach, University of Chicago

Stochastic Quantum Chemistry

Exact many-particle quantum mechanics has a prohibitive cost that grows exponentially with the size of the system. Most modern quantum chemistry is built on approximations that result in more tractable algorithms with polynomial scaling, but which qualitatively fail for many important problems. I will describe an alternative approach that uses stochastic techniques to circumvent this prohibitive cost (i.e. a flavor of quantum Monte Carlo). In particular, this approach is based on a very general and recently-developed framework for stochastic linear algebra called "fast randomized iteration", due to Lim and Weare. I will describe the FRI algorithm, its application to challenging problems in quantum chemistry, and its advantages over similar techniques.
Computations in Science

October 31, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - Prof. Christos Panagopoulos, Nanyang Techenilogical University, Singapore

Tunable Room Temparature Skyrmions

The electric field experienced by a travelling electron translates, in its rest frame, to a magnetic field proportional to its velocity – a relativistic effect which is notable in crystalline lattices with heavy atoms. The Zeeman interaction between the electron spin and this effective magnetic field is equivalent to the coupling of the electronic spin and momentum degrees of freedom, known as spin-orbit coupling (SOC). Importantly, SOC effects are greatly enhanced in reduced dimensions: inversion symmetry is broken at the surface or interface, and the resultant electric field couples to the spin of itinerant electrons. Host: Timothy Berkelbach, 4-9879 or via email to berkelbach@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.

The states induced by engineering SOC and inversion symmetry breaking in magnetic materials open a broad perspective, with impact in the technology of spin topology. For example, in conventional ferromagnets the exchange interaction aligns spins and the anisotropy determines energetically preferred orientations. Meanwhile, the interaction generated by SOC and broken inversion symmetry induces a relative tilt between neighbouring spins. Magnetic skyrmions – finite-size two-dimensional (2D) ’whirls’ of electron spin – form due to the competition between these ‘winding’ & ‘aligning’ exchange interactions.

Skyrmions have several compelling attributes as prototype memory elements, namely their (1) nontrivial spin topology, protecting them from disorder and thermal fluctuations, (2) small size and self-organization into dense lattices and (3) particle-like dynamics, manipulation and addressability. Using a novel materials architecture we developed recently, I will address quantifiable insights towards understanding skyrmion stability and dynamics, and directions for exploiting their properties in nanoscale devices at room temperature.
The Tuesday JFI Seminar

October 30, 2018
GCIS W301 | Tuesday, 4:00 pm

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Yizhi You, Princeton Center for Theoretical Physics

Fracton phase of matter: Lattice models, gauge theories and realizations

Fracton phase of matter shares many features of topological order, including long-range entangled ground states and non-trivial braiding statistics. At the same time, fracton phase contains subextensive ground-state degeneracy and the restricted mobility of quasiparticle which exclude itself from the TQFT paradigm. In this talk, I start from several fracton lattice models and demonstrate their relation with gauged subsystem symmetric SPT phase. Further, I will present a theoretical framework for higher Chern-Simons theory in 3D which realizes a deconfined U(1) fracton phase. In the end, I propose an experiment platform for realizing diverse fracton stabilizer codes based on interacting nanowires, which enables us to fabricate a zoology of fracton states and thus provides a powerful novel avenue to the realization of stable quantum memory and fault-tolerant quantum computing.
Kadanoff Seminar

October 30, 2018
PRC 201 | Tuesday, 12:00 pm

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Professor Daniel Palanker, Department Ophthamology & Hansen Experimental Physics Laboratory, Stanford University

Photovoltaic Restoration of Sight in Retinal Degeneration

Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well preserved. Information can be reintroduced into the visual system using electrical stimulation of the surviving inner retinal neurons. Some electronic retinal prosthetic systems have been already approved for clinical use, but they provide low resolution and involve very difficult implantation procedures. We developed a photovoltaic subretinal prosthesis which converts light into pulsed electric current, stimulating the nearby inner retinal neurons. Visual information is projected onto the retina from video goggles using pulsed near- infrared (~880nm) light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity. Optical activation of the photovoltaic pixels allows scaling the implants to thousands of electrodes.

In preclinical studies, we found that prosthetic vision with subretinal implants preserves many features of natural vision, including flicker fusion at high
frequencies (>20 Hz), adaptation to static images, center-surround organization and non-linear summation of subunits in receptive fields, providing high spatial resolution. Initial results of the clinical trial with our implants (PRIMA, Pixium Vision) having 100µm pixels, as well as preclinical measurements, confirm that spatial resolution of prosthetic vision can reach the sampling density limit. For a broad acceptance of this technology by millions of patients who lost central vision due to age-related macular degeneration, visual acuity should exceed 20/100, which requires pixels smaller than 25µm. I will describe the fundamental limitations in electro-neural interfaces and 3-dimensional configurations which should enable such a high spatial resolution. Ease of implantation of these wireless modules, combined with high resolution opens the door to highly functional restoration of sight.
Host: Bozhi Tian, 2-8749 or via email at btian@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
Special JFI Seminar

October 29, 2018
GCIS W301 | Monday, 1:30 pm

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Professor Matthew Kanan, Stanford University

Re-sourcing Chemicals

This talk will describe our recent efforts to turn CO2 into a carbon source for commodity chemicals. Our goal is to develop scalable processes in which the use of CO2 affords a clear chemical advantage over conventional fossil fuel–based routes. I will first describe new carboxylation chemistry to generate (di)-carboxylic acids that have high-volume applications. Conventional carboxylation methodology relies on extremely energy-intensive reagents. We have found systems in which simple carbonate salts deprotonate un-activated C–H bonds, generating carbon-centered nucleophiles that react with CO2 to form C–C bonds. As one application, we used this chemistry to develop a high-yielding route from inedible biomass to furan-2,5-dicarboxylic acid (FDCA), a monomer that is currently being pursued as a replacement for terephthalic acid in polyester synthesis. To generalize this strategy, we have recently developed nanostructured carbonates that can perform hydrocarbon C–H insertion. In a two-step cycles, these materials convert arenes, CO2, and alcohols into aromatic esters with no use of stoichiometric reagents or generation of waste products. In the second part of my talk, I will describe our work on electrochemical systems for generating C2 feedstock chemicals. We have pioneered the use of grain boundaries to create metastable active surfaces for CO2 and CO reduction and recently elucidated a structural model to explain grain boundary effects. I will discuss the prospects for exploiting grain boundary effects in electrosynthesis and the design of prototype reactors that provide high synthesis rates and concentrated product streams.
Chemistry

October 29, 2018
Kent 120 | Monday, 1:15 pm

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Professor Jiaoyang Jiang, University of Wisconsin-Madison

Specificity, Function and Regulation of Protein O-GIcNAc Modification

The N-acetylglucosamine (O-GlcNAc) modification is an essential glycosylation that has been identified on over 1,000 proteins. It dynamically modulates protein functions and regulates numerous biological processes in physiology and disease. O-GlcNAc modification is added by O-GlcNAc transferase (OGT) and removed by O-GlcNAcase (OGA). Despite recent progress, challenges remain to decipher the biological roles of O-GlcNAc modification and its regulation by OGT and OGA on a broad range of substrates that lack an apparent sequence motif. In this talk, I will present our recently developed structural biology and chemical biology approaches to start revealing the specificity, function and regulation of O-GlcNAc modification.
Chemistry

October 26, 2018
Kent 120 | Friday, 1:15 pm

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William Irvine, University of Chicago

Spinning Top-ology

Geometry, topology and broken symmetry play a powerful role in determining the physics of materials. In this colloquium I will talk of activated materials and fluids built out of mechanically spinning components and show how the subtle interplay of structure, time-reversal and parity leads to `odd' solid and fluid mechanics. In particular I will discuss a simple kind of active meta-material – coupled gyroscopes – that naturally encodes non-trivial topology in its vibrational spectrum. In particular, I will show how topology can emerge not only in ordered gyro materials but also their amorphous counterparts. We will then foray into activated colloidal gyro fluids and see how breaking symmetry under parity leads to chiral surface states and odd instabilities driven by viscous forces. We will use these chiral waves as a tool to observe the presence of odd (or Hall) viscosity in our chiral fluid.
Physics Colloquium

October 25, 2018
KPTC 106 | Thursday, 4:00 pm

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Professor Marc Fontecave, Collège de France

FeS Clusters and Thiolation Reactions: Lessons from tRNA- and Protein-modifying Enzymes

Living cells are full of molecules containing sulfur atoms, for example biotin, lipoic acid, thiamin but also a variety of nucleosides within transfer RNAs and inorganic cofactors such as iron-sulfur (FeS) clusters. However, how these compounds are biosynthesized and how sulfur atoms are incorporated into organic substrates are still open fascinating questions. The discovery that important enzymes involved in thiolation reactions are FeS enzymes belonging to the Radical-SAM (S-Adenosyl-Methionine) enzyme superfamily, such as biotin synthase or lipoate synthase, has suggested a novel function for FeS clusters. It is proposed that they serve, in these enzymes, as a sulfur storage system from which sulfur atoms can be delivered to activated substrates during thiolation. The chemistry of Radical-SAM enzymes in the specific context of these reactions will thus be presented. However, other results, in particular from our laboratory, have challenged this theory since we have shown, during our functional and structural characterization of tRNA- and protein-sulfurating FeS enzymes (methylthiotransferases and thiolases) that thiolation can occur without mobilization of the sulfur atoms of the FeS clusters. Here we discuss these alternative mechanisms.
Chemistry

October 25, 2018
Kent 120 | Thursday, 1:15 pm

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Pedro Saenz, MIT

Spin lattices of walking droplets

Understanding the self-organization principles and collective dynamics of non-equilibrium matter remains a major challenge despite considerable progress over the last decade. In this talk, I will introduce a hydrodynamic analog system that allows us to investigate simultaneously the wave-mediated self-propulsion and interactions of effective spin degrees of freedom. Millimetric liquid droplets can walk across the surface of a vibrating fluid bath, self-propelled through a resonant interaction with their own guiding wave fields. A walking droplet, or ‘walker', may be trapped by a submerged circular well at the bottom of the fluid bath, leading to a clockwise or counter-clockwise angular motion centered at the well. When a collection of such wells is arranged in a 1D or 2D lattice geometry, a thin fluid layer between wells enables wave-mediated interactions between neighboring walkers. Through experiments and mathematical modeling, we demonstrate the spontaneous emergence of coherent droplet rotation dynamics for different types of lattices. For sufficiently strong pair-coupling, wave interactions between neighboring droplets may induce local spin flips leading to ferromagnetic or antiferromagnetic order. Transitions between these two forms of order can be controlled by tuning the lattice parameters. More generally, our results reveal a number of surprising parallels between the collective spin dynamics of wave-driven droplets and known phases of classical condensed matter systems. This suggests that our hydrodynamic analog system can be used to explore universal aspects of active matter and wave-mediated particle interactions, including spin-wave propagation and topologically protected dynamics far from equilibrium.
Computations in Science

October 24, 2018
KPTC 206 | Wednesday, 12:15 pm

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Barry Bradlyn, UIUC

Wilson Loops, Wyckoff Positions, and Wannier Functions: New Developments in Stable and Fragile Topology

The interplay of topology and geometry has been -- and continues to be -- a rich area of study for condensed matter physics. Recently, we have realized that spatial symmetries allow for the stabilization of topological phases much more exotic than those that can be found with time-reversal symmetry alone. Examples include topological crystalline insulators, "hourglass Fermion" phases, and Dirac and double-Weyl semimetals. In this talk, I will review recent developments in the theory of band representations which highlight the role of Wannier functions and holonomy in explaining the origins of topological crystalline behavior. I will show how this relates to several new ideas, such as symmetry indicators, topological phases with high co-dimension boundary states, and the "fragile" topology of isolated groups of bands. Finally, I will discuss how non-symmorphic symmetries can protect novel topological surface states, which can be diagnosed through the holonomy of Bloch functions.
Kadanoff Seminar

October 24, 2018
PRC 201 | Wednesday, 11:00 am

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MRSEC Surface Metrology Workshop

in cooperation with Olympus


8:30 AM : Breakfast
9:00 AM: Introduction to LEXT OLS5000 Laser Confocal Microscope, Guangnan Meng, PhD
10:00 AM: Coffee Break
10:15 AM: MRSEC Student Talks: Applications
11:30 AM: A Few Things You Need to Know About Surface Roughness: Guangnan Meng, PhD
12:15 PM: Lunch (registration required)
1:00 PM - 5:00 PM: Sample Demonstrations and Discussions


Please register online for free lunch and sample demos
https://www.surveymonkey.com/r/9QBQFRN
MRSEC Workshop

October 24, 2018
GCIS W301 | Wednesday, 9:00 am

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Prof. Michael Grünwald, Department of Chemistry, University of Utah

Orientational Order in Self-Assembled Nanocrystal Superlattices

Self-assembly of nanocrystals into functional materials requires precise control over nanoparticle interactions in solution, which are dominated by organic ligands that densely cover the surface of nanocrystals. In this talk, I will present a computational study of ligand effects in the self-assembly of small, non-spherical nanocrystals. We focus on nanocrystals with cuboctahedral and truncated octahedral shape and determine their self-assembly behavior as a function of ligand length and solvent quality. Our model, which is based on a coarse-grained description of ligands and a schematic representation of solvent effects, reproduces the experimentally observed superstructures, including recently observed superlattices with partial and short-ranged orientational alignment of nanocrystals. We show that small differences in nanoparticle shape, ligand length and coverage, and solvent conditions, can lead to markedly different self-assembled superstructures due to subtle changes in the free energetics of ligand interactions. Our results help explain the large variety of different reported superlattices self-assembled from seemingly similar particles and can serve as a guide for the targeted self-assembly of nanocrystal superstructures. Host: Suri Vaikuntanathan, 2-7256 or via email at svaikunt@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

October 23, 2018
GCIS W301 | Tuesday, 4:00 pm

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Professor Marc Fontecave, Collège de France

Carbon Dioxide to Fuels: from Enzymes to Bioinspired Catalysts


Chemistry

October 23, 2018
Kent 120 | Tuesday, 1:15 pm

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Yuhai Tu, PhD, IBM

Nonequilibrium physics in biochemical oscillations

A central problem in systems biology is how living systems manage to perform precise functions (development, replication, signaling, etc.) by using inherently noisy biochemical networks. What are the molecular mechanisms for control? What are the design principles for the underlying biochemical networks? What are the energy costs for regulation? In this talk, we will present some recent results to address these general questions in biochemical oscillatory systems. We will discuss the molecular mechanism and energy cost for enhancing the accuracy and synchronization of biochemical oscillators [1]; and the design principles for oscillatory biochemical networks to achieve both high entrainability and low phase fluctuations [2].
[1] “The free-energy cost of accurate biochemical oscillations”, Y. Cao, H. Wang, Q. Ouyang, and Yuhai Tu, Nature Physics, 11, 772, 2015.
[2] “Design principles for enhancing phase sensitivity and suppressing phase fluctuations simultaneously in biochemical oscillatory systems”, C. Fei, Y. Cao, Q. Ouyang, and Yuhai Tu, Nature Communications, doi:10.1038/s41467-018-03826-4, 2018.
Biophysical Dynamics

October 23, 2018
GCIS W301 | Tuesday, 12:00 pm

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Chemistry Colloquium: Professor Naoto Chatani, Osaka University

Development of New Catalytic Reactions Involving the Activation of Traditionally Inert Bonds

Organic molecules contain a variety of chemical bonds. Organic synthesis involves the cleavage of a chemical bond and the formation of a new chemical bond. However, not all of the chemical bonds in organic molecules have been used in organic synthesis. Thus, organic synthesis is heavily dependent on the reactivity of chemical bonds. If so-called unreactive bonds were to be used directly in organic synthesis, new possibilities for developing new synthetic methodologies would arise. We have utilized, not only the activation of C-H bonds, but also the activation of unreactive single bonds, such as C-C, C-O, C-N, and C-F bonds, and the activation of C-C triple bonds and C-O double bonds, in our quest to develop new types of transformations that will lead to further diversification in the field of organic synthesis.
Chemistry

October 22, 2018
Kent 120 | Monday, 4:00 pm

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Professor Michael J. Hatridge, Department of Physics, University of Pittsburgh

Qubit Measurement with Two-Mode Squeezed Light

High fidelity qubit measurement is essential for scalable, fault-tolerant quantum computing. In superconducting circuits, qubit readout with fidelity above 99% has been achieved by using a quantum-limited parametric amplifier such as the Josephson Parametric Converter (JPC) as the first stage amplifier. However, the Signal-to-Noise Ratio (SNR) of such readout is fundamentally limited by quantum fluctuations in the coherent readout pulse. Alternatively, readout with squeezed light can be used to reduce fluctuation along certain quadratures and thus improve the SNR. In this talk, we demonstrate a readout scheme with two-mode squeezed light both produced and amplified by JPCs in an interferometer unbalanced by a transmon qubit/cavity. This configuration has been predicted to improve the SNR compared to readout with both coherent states and single-mode squeezed light. We have demonstrated a 50% improvement in SNR compared to coherent state readout, and find that the system actual works best when when we deliberately break the path for signals in the system, so that only the fluctuations passing through it interfere. We'll also discuss the prospects for placing qubits on both arms of the interferometer and performing measurements which generate remote entanglement between them.
JFI Special Seminar

October 22, 2018
GCIS E223 | Monday, 3:30 pm

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Inorganic/Organic Seminar: Professor Hemamala Karunadasa, Stanford University

Between the Sheets: The Molecular Chemistry of Hybrid Perovskites

The tools of synthetic chemistry allow us to tune molecules with a level of precision not yet accessible with inorganic solids. We have investigated hybrid perovskites that couple organic small molecules with the optical and electronic diversity of extended inorganic solids. I will share our current understanding of these materials, whose technologically relevant properties are highly amenable to synthetic design.
The 3D lead-iodide perovskites have recently been identified as low-cost absorbers for high-efficiency solar cells. Although the efficiencies of devices with perovskite absorbers have risen at an impressive rate, the materials’ intrinsic instability and toxicity may impede their commercialization. I will discuss methods developed by our group to address these problems. The 2D hybrid perovskites have dramatically different properties from their 3D congeners. We discovered that some 2D perovskites emit broadband white light (similar to sunlight) when excited by UV light. I will discuss how these materials, which do not contain extrinsic dopants or obvious emissive sites, could emit every color of visible light. Although the organic molecules in hybrid perovskites have mostly played a templating role, we have investigated their role in engendering reactivity. I will describe reactions that occur between the inorganic sheets, which allow these nonporous solids to capture small molecules.
Chemistry

October 19, 2018
Kent 120 | Friday, 1:15 pm

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Can a large packing be assembled from smaller ones ?

Eat 12
Answer revealed 12:15
MRSEC Baglunch

October 19, 2018
GCIS E123 | Friday, 12:00 pm

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Jean Dalibard, Collège de France

Exploring Flatland with cold atoms

The physics of many-body systems strongly depends on their dimensionality. For example, in a two-dimensional world, most standard phase transitions towards an ordered state of matter like crystals or magnets would not occur because of the increased role of fluctuations. However, non-conventional phase transitions can still take place, as understood by Kosterlitz and Thouless (2016 Nobel prize). In this talk I will present some important features of Flatland physics explored with cold atomic gases, such as the existence of a superfluid transition that occurs in the absence of Bose-Einstein condensation. I will also discuss out-of-equilibrium properties of these atomic 2D gases, in connection with the so-called Kibble-Zurek mechanism.
Physics Colloquium

October 18, 2018
KPTC 106 | Thursday, 4:00 pm

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IME Distinguished Colloquium Series - Prashant Kamat

Professor Prashant Kamat from University of Notre Dame will speak as part of the IME Distinguished Colloquium Series.

Event will be followed by a reception from 5 pm to 6 pm at ERC in IME’s 2nd floor lounge/atrium area
Molecular Engineering

October 17, 2018
KCBD 1103 | Wednesday, 4:00 pm

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Peizhi Du, Maryland University

Hybird seesaw leptogenesis and TeV singlets

The appealing feature of inverse seesaw models is that the neutrino mass emerges from the exchange of TeV scale singlets with sizable Yukawa couplings, which can be tested at colliders. However, the tiny Majorana mass splitting between TeV singlets is left unexplained. Moreover, we argue that these models suffer from a structural limitation that prevents a successful thermal leptogenesis if Yukawa couplings are unsuppressed. In this talk, I will introduce a hybrid seesaw model, where we replace the mass splitting with a coupling to a high scale seesaw module including a TeV scalar. I will show that this structure achieves the goal of filling both the above gaps with couplings of order unity. The necessary structure automatically arises embedding the seesaw mechanism in composite Higgs models. Our hybrid seesaw models have an interesting interplay between high scale and TeV scale physics in leptogenesis and enlarges the range of allowed high scale singlet masses.
Theory Seminar

October 17, 2018
PRC 201 | Wednesday, 1:30 pm

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Andrew Ferguson, University of Chicago

Machine learning design of self-assembling colloidal crystals and inference of protein folding funnels

Data-driven modeling and machine learning have opened new paradigms and opportunities in the understanding and design of soft and biological materials. Colloidal particles with tunable anisotropic surface interactions are of technological interest in fabricating responsive actuators, biomimetic encapsulants, and photonic crystals with omnidirectional band gaps. In the first part of this talk, I will describe our applications of nonlinear manifold learning to determine low-dimensional assembly landscapes for self-assembling patchy colloids. These landscapes connect colloid architecture and prevailing conditions with emergent assembly behavior, and enable inverse building block design by rational sculpting of the landscape to engineer the stability and accessibility of desired aggregates. Rational engineering of structural and functional polymers and proteins requires an understanding of the underlying free energy landscapes dictating thermodynamic stability and kinetic folding pathways. In the second part of this talk, I will describe an approach integrating ideas from dynamical systems theory and nonlinear manifold learning to reconstruct multidimensional protein folding funnels from the time evolution of single experimentally-measurable observables.
Computations in Science

October 17, 2018
KPTC 206 | Wednesday, 12:15 pm

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Lee Lecture: Professor Susumu Kitagawa, Kyoto University

Chemistry and Application of Soft Porous PCP/MOF

e have found unique porous properties of PCPs/MOFs, which possess flexible or dynamic porous frameworks, reversibly responding to external stimuli, not only chemical but also physical. They were developed in an effort to realize dynamic porous and collective functionality not found in conventional materials. Their compositions of metal ions and organic molecules have achieved diversity in the electronic states. That is, the spatial and electronic structures can be altered, realizing magnetic and dielectric properties as well as oxidation− reduction functions. Besides normal storage, such MOFs have vast potential for separation with an extremely high selectivity, high-efficiency storage, and catalysis, as well as sensing and actuator functions. For these reasons, many studies investigate these materials. In this lecture, I discuss porous materials with capabilities that exceed current ones and the future research direction.
Chemistry

October 17, 2018
GCIS W301 | Wednesday, 12:00 pm

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Jessica M.J. Swanson, The University of Chicago

Unraveling Multistep Kinetic Mechanisms Behind Coupled Ion Exchange: A Case Study on Cl-/H+ Exchangein ClC Antiporters

Understanding complex mechanisms such as transmembrane ion exchange by proteins in molecular, thermodynamic, and kinetic detail remains a significant challenge. In this talk, I will present a new approach to integrate experimental and simulation data to fully characterize Cl–/H+ exchange in ClC antiporters. Rate coefficients are first calculated with reactive and polarizable molecular dynamics simulations and then optimized within a coupled kinetic (Markov state) model to reproduce experimental data. This produces a set of solutions that not only predict new properties but also reveal insight into the series of transitions that define the mechanism, the molecular origin of the unusual 2.2:1 Cl–/H+ stoichiometry, and the influence of protein orientation. I will explain how the consistent exchange ratio is a consequence of kinetic coupling and how the lack of large protein conformational changes suggests a more facile evolutionary connection between chloride channels and more evolved antiporters. Finally, I will discuss how an ensemble of different stochastic exchange pathways, as opposed to a single series of distinct transitions, culminates in the macroscopic observables and thereby helps to explain the underlying molecular mechanism.
Biophysical Dynamics

October 16, 2018
GCIS W301 | Tuesday, 12:00 pm

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Lee Lecture: Professor Susumu Kitagawa, Kyoto University

Porous Coordination Polymers/Metal Organic Frameworks

Permanent porosity for coordination networks in solids was discovered and demonstrated with gas sorption experiments (1997), whose materials are now known as porous coordination polymers (PCPs) or metal-organic frameworks (MOFs). They are an emerging class of microporous solids combining the modularity of inorganic structural building units (nodes) with organic ligands (linkers) that can be tailored through organic synthesis. This particular combination of designability and the structural porosity of MOFs has led to explosive growth in their application to gas storage/separation, catalysis, ion conductivity, chemical sensing, and drug delivery systems. To date, MOFs are classified as a new category of porous materials, as opposed to the conventional classifications of inorganic and carbon materials. Researchers in the world synthesized a wide variety of MOFs and developed the comprehensive structural chemistry. We have developed the chemistry of coordination space, focusing on functionalities, and discovered flexible MOFs (soft porous crystals) which to date are another dimension of porous materials.
MOFs have been extensively researched in both academia and industry. Industrial syntheses are rapidly advancing. Researchers in both academia and industry are producing MOFs materials for use in purification, storage, transportation, and conversion, vital to addressing energy and environmental issues and contributing to human welfare.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

October 15, 2018
Kent 120 | Monday, 4:00 pm

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Dr. Christa Flühmann, Department of Physics, ETH Zurich

An Encoded Qubit in a Trapped-ion Oscillator

I will present recent experiments demonstrating a qubit encoded in the harmonic motion of a single trapped 40Ca+ ion [1]. The usage of the oscillator allows to study a logical qubit with a single quantum system, while in contrast commonly used error-correction schemes are based on arrays of many physical qubits. The approximate logical code states are formed from a periodically spaced superposition of displaced squeezed components, which has theoretically been shown to have optimal performance for a large set of errors [2, 3]. Our first time demonstration of these qubits is based on coupling the ion motional oscillator to an internal state ancillary qubit, which we can subsequently readout. This indirect readout of the oscillator via the ancillary qubit we have previously interpreted as a modular position or momentum measurement and explored the relations between sequences of these measurements [4]. Such sequences allow us to create the logical codes states as well as measure their spatial and momentum probability densities, revealing the non-local features simultaneously present in both densities. Using the modular measurements we further implement logical state readout in the Pauli basis which we demonstrate on the six cardinal states of the Bloch sphere for which we reach an average square fidelity of 87.3 ± 0.7%. We implement the logical Pauli gates by displacements of the oscillator and realize arbitrary single qubit operations by modifying the modular measurements slightly. We analyze the performance of a universal single logical qubit gate set by performing process tomography, for Pauli gates we reach process fidelities of ≈ 97%, while for continuous rotations we achieve fidelities of ≈ 89%.
JFI Special Seminar

October 15, 2018
GCIS E223 | Monday, 3:30 pm

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MRSEC Lunch 'n Learn Workshop

HORIBA Duetta Fluorescence and Absorbance Spectrometer

Come see the worlds’ fastest 2 in 1 Fluorescence and Absorbance Spectrometer
Duetta
A Game Changing Spectrometer Concept
• UV-Vis-NIR Fluorescence Detection Wavelength Range from 250 to 1,100 nm
• Full 3-D Fluorescence EEM Acquisition in Less Than One Second
• Best in Class Fluorescence Sensitivity Specification of 6,000:1 RMS for Water Raman
• Automatic Correction for Primary
and Secondary Inner Filter Effects (IFE)
• High Fidelity Molecular Fingerprinting with Unique A-TEEMTM
(Absorbance-Transmittance Excitation Emission Matrix) Technology
• Millisecond CCD Detection of Entire Fluorescence Spectrum
MRSEC Workshop

October 12, 2018
ERC 301B | Friday, 11:30 am

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Stephan Meyer

Equity, Diversity and Inclusion


Physics Colloquium

October 11, 2018
KPTC 106 | Thursday, 4:00 pm

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Paul Oehlmann, Virgina Tech

Gauged Superconformal matter from exotic F-theory fibrations

We consider 6 dimensional supergravity theories coupled to gauged superconformal matter. The physics is extracted from F-theory on smooth torus fibered Calabi-Yau threefolds. The superconformal matter resides at points in the base of the fibration that are either smooth, in the case of (1,0) superconformal matter, or orbifold singularities in the (2,0) case.
Smoothness of the the full geometry implies exotic fiber behavior over those points
such as non-flat and multiple fibers that we analyze in detail. The topology of those
fibers and the full geometry allows an interpretation for the superconformal matter which
can be verified by analyzing their deformation spaces.
Theory Seminar

October 10, 2018
PRC 201 | Wednesday, 1:30 pm

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Shinsei Ryu, University of Chicago

Topology and entanglement detected by partial transpose

Quantum many-body systems exhibit very rich phenomena unexpected from their classical counterparts. In this talk, I will focus on a quantum information theoretical operation -- partial transpose -- which is useful in detecting quantum entanglement. I will describe how partial transpose can be used to detect topology and entanglement in quantum many-body systems, ranging from topological phases of condensed matter to systems which have holographic dual descriptions. In particular, I will describe the constructions of topological invariants using partial transpose, and possible holographic dual objects corresponding to entanglement negativity, which is an quantum entanglement measure constructed by using partial transpose.
Computations in Science

October 10, 2018
KPTC 206 | Wednesday, 12:15 pm

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Omrie Ovdat, Technion

Vacancies in Graphene: Dirac Physics and Fractional Vacuum Charges

Significant interest has lately been devoted to the study of vacancies in graphene obtained by removing a neutral carbon atom. The presence of a single vacancy has interesting and unexpected consequences. It leads to the occurrence of a stable charge of order unity localized at the vacancy site and interacting with other charges of the conductor by means of an Coulomb potential. It also breaks the symmetry between the two triangular graphene sublattices hence inducing zero energy states at the Dirac point. These features have been noticed, however, their precise underlying mechanism and its relation to Dirac physics, if any, are yet to be investigated. Here we show the fractional and pseudo-scalar nature of this stable vacancy charge originating from the vacuum and insensitive to screening effects. A continuous Dirac model is presented which relates zero modes to vacuum fractional charge and to parity symmetry breaking. This relation, constitutes an Index theorem and is achieved by using particular chiral boundary conditions, which map the vacancy problem onto edge state physics and link zero energy states to topological features of the bulk alike the Hall effect or physics of kinks, vortices and monopoles. Vacancies in graphene thus allow to realize prominent features of $2+1$ quantum electrodynamics, e.g., charge fractionalization and parity breaking, but without coupling to a gauge field.This essential difference makes vacancy physics relatively easy to implement and an interesting playground for topological charge switching.
Kadanoff Seminar

October 9, 2018
PRC 201 | Tuesday, 4:00 pm

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JFI Tuesday Seminar - Prof. Jean Dalibard - College de France

Topological Protection in Quantum Gases

How can one classify the states of matter? Beyond well-known
arguments based on geometrical symmetries, the application of concepts
originating from topology is currently leading to fascinating
developments. These concepts were initially proposed in condensed matter
physics in order to describe the Quantum Hall effect, and they are now
spreading over many fields of research, notably in atomic physics and
optics. In this lecture, I will present some robust properties that
characterize topological matter formed with atomic gases, which persist
when one modifies the system parameters or add some disorder. I will
also explain how these concepts can lead to novel devices that take
advantage of topological robustness. Host: Cheng Chin, 2-7192 or via email to cchin@jfi.uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

October 9, 2018
GCIS W301 | Tuesday, 4:00 pm

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Nathan Seiberg, IAS

Recent advances in 2+1d QFT

We will review recent developments in the study of quantum field theory in 2+1 dimensions. Newly discovered subtleties in the analysis of the short distance behavior of these theories have uncovered surprising properties. They help motivate a rich web of conjectures about the long distance behavior of these systems. These conjectures describe new phases and new phase transitions between them. Also, in many cases these transitions have several different dual descriptions. These new developments were motivated by ideas in high energy physics, string theory, and condensed matter physics. And they have potential applications in these fields.
Kadanoff Seminar

October 9, 2018
PRC 215 | Tuesday, 1:30 pm

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Chemistry Colloquium: Professor Masaru Kuno, University of Notre Dame

Single Semiconductor Nanostructure Extinction Spectroscopy

There has been thirty years of emission-based single particle microscopy and spectroscopy since Moerner’s seminal single molecule study. While highly successful in revealing the properties of matter hidden by ensemble averages, the limits of emission-based microscopies have now become apparent. To address recognized future needs and, in particular, the need to go beyond fluorescent specimens, single particle extinction techniques have been developed. Motivating this has been the desire to acquire information about the electronic structure of nanoscale materials difficult to obtain otherwise using either ensemble or emission-based single particle measurements. Circumstances where single particle extinction measurements offer superior alternatives to traditional microscopies/spectroscopies include situations where the material of interest is non-emissive or where current syntheses yield ensembles with large size and/or compositional distributions that hide the underlying spectral response of a material. Most relevant, though, are cases where information about the underlying electronic structure of a material -something directly encoded in its absorption- is less forthcoming and is at best inferred indirectly using emission-based approaches.
This talk describes the inherent problems associated with measuring the extinction of low dimensional semiconductors. It simultaneously describes the fundamental operating principles of two common extinction techniques while highlighting their achievements. It then reviews what exactly we have learned about the fundamental physics of CdSe, a model semiconductor nanosystem. The talk ends by describing the future development of new single particle extinction methodologies such as infrared photothermal heterodyne imaging.
Chemistry

October 8, 2018
Kent 120 | Monday, 4:00 pm

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Inorganic/Organic Seminar: Professor Keary Mark Engle, The Scripps Research Institute

Catalytic Methods for Selective Functionalization of C–C π-Bonds

Vicinal (1,2-disubstituted) functional group motifs are ubiquitous in structurally complex small molecules that are of academic and industrial importance, including many widely used pharmaceutical agents. Many such functional group combinations, however, remain exceptionally challenging to synthesize. The goal of research in the Engle lab is to develop a general catalytic platform for alkene and alkyne difunctionalization to introduce a diverse array of functional groups at each of the two carbon atoms in a programmable fashion. Our central hypothesis is that is that coordination of a π-Lewis acidic metal, such as palladium(II), to the alkene will promote nucleophilic attack and that the resultant organometallic species can be trapped with an electrophile to furnish the desired 1,2-difunctionalized product. In the overall net transformation, one of the two new functional groups is introduced in the form of a nucleophile, and the other in the form of an electrophile. Directing groups are used to control the regiochemical course of the reaction and stabilize key alkylmetal intermediates. These concepts have been used to expand the synthetic toolkit to include new retrosynthetic disconnections, including “homo-Michael” addition and β,γ-vicinal dicarbofunctionalization of alkenyl carbonyl compounds.
Chemistry

October 5, 2018
Kent 120 | Friday, 1:15 pm

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David Schimitz, University of Chicago

Neutrino Physics at Long and Short Baselines: The DUNE and SBN Experiments at Fermilab

The study of neutrinos over the past 60 years has revealed an incredible amount about the Standard Model of elementary particles, despite neutrinos being one of the most challenging areas of exploration in particle physics. This combination, a seeming contradiction, motivates continued experimental effort at a grand scale to reveal the neutrinos’ further secrets. One of the global centers of neutrino physics research is at Fermilab, forty miles west of campus, which hosts the future Deep Underground Neutrino Experiment, DUNE, and the ongoing Short-Baseline Neutrino experiment, SBN. In this talk, I will review some of the biggest past discoveries in neutrino physics and preview the exciting future ahead with these new experiments at unprecedented scales and with world-leading reach for new discoveries.
Physics Colloquium

October 4, 2018
KPTC 106 | Thursday, 4:00 pm

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Xiao Chen, KITP, UC Santa Barbara

Operator dynamics and quantum chaos: an approach from Brownian circuit

Operator scrambling is a crucial ingredient of quantum chaos. Specifically, in the quantum chaotic system, a simple operator can become increasingly complicated under unitary time evolution. This can be diagnosed by various measures such as square of the commutator (out-of-time-ordered correlator), operator entanglement entropy etc. In this talk, we discuss operator dynamics in three representative models: a 2-local spin model with all-to-all interaction, a chaotic spin chain with long-range interactions, and the quantum linear map. In the first two examples, we explore the operator dynamics by using the quantum Brownian circuit approach and transform the operator spreading into a classical stochastic problem. Although the speeds of scrambling are quite different, a simple operator can eventually approach a "highly entangled" operator with operator entanglement entropy taking a volume law value (close to the Page value). Meanwhile, the spectrum of the operator reduced density matrix develops a universal spectral correlation which can be characterized by the Wishart random matrix ensemble. In contrast, in the third example (the quantum linear map), although the square of commutator can increase exponentially with time, a simple operator does not scramble but performs chaotic motion in the operator basis space determined by the classical linear map. We show that once we modify the quantum linear map such that operator can mix in the operator basis, the operator entanglement entropy can grow and eventually saturate to its Page value, thus making it a truly quantum chaotic model.
Kadanoff Seminar

October 4, 2018
PRC 215 | Thursday, 2:30 pm

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Special Seminar: Professor Li Deng, Brandeis University / Westlake University

Activation of Nucleophiles for Asymmetric Reaction with Organic Molecules

Organic molecule-mediated selective catalysis (i.e. selective organocatalysis) has evolved into a generally applicable, powerful strategy for asymmetric synthesis over the past few years. This lecture will present synthetic and mechanistic studies focusing on the development of weak-bonding organocatalysis directed towards the activation of nucleophiles for realizing asymmetric transformations of synthetic importance.
Chemistry

October 4, 2018
GCIS W301 | Thursday, 2:30 pm

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Marija Vucelja, University of Virginia

Adaptation of a bacterial population and the adaptive immune system of bacteria with CRISPR

The CRISPR (clustered regularly interspaced short palindromic repeats) mechanism allows bacteria to defend adaptively against phages and other invading genomic material. The CRISPR machinery acquires short genomic sequences from the "invaders" and in this way builds up a memory of past infections. With a new encounter of an invading sequence, this memory is accessed, and in a successful outcome, the invader is neutralized. I will introduce a population dynamics model where immunity can be both acquired and lost. I will describe the predictions of this model and suggest experiments.

Adaptation, where a population evolves increasing _x000C_fitness in a fixed environment is often thought of as a hill climbing process on a _x000C_fitness landscape. With a fi_x000C_nite genome, such a process eventually leads the population to a _x000C_fitness peak, at which point _x000C_fitness can no longer increase through individual beneficial mutations. Instead, the ruggedness of typical landscapes due to epistasis between genes or DNA sites suggests that the accumulation of multiple mutations can allow the population to continue increasing in _x000C_fitness. By using a spin-glass type model for the _x000C_fitness function that takes into account microscopic epistasis, we _x000C_find that hopping between metastable states can mechanistically and robustly give rise to a slow, logarithmic average _x000C_fitness trajectory.
Computations in Science

October 3, 2018
KPTC 206 | Wednesday, 12:15 pm

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IME Distinguished Colloquium Series - Arup Chakraborty

Professor Arup Chakraborty from Massachusetts Institute of Technology will kick off the IME Distinguished Colloquium Series with an hour-long talk.
Molecular Engineering

October 3, 2018
ERC 161 | Wednesday, 11:00 am

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1st Tuesday Colloquium - Prof. David DeMille, Yale University

Diatomic Molecules as Quantum Tools

Our group is pursuing a wide range of physics goals, by applying techniques of modern atomic physics to the more complex system of diatomic molecules. For example, we use the strong electric field inside a polar molecule to amplify the observable effect from an electric dipole moment (EDM) of the electron, a CP-violating effect predicted in many extensions to the Standard Model of particle physics. We recently set a new upper limit on the electron EDM, placing severe bounds on many models of new physics at the TeV energy scale. In parallel, our group has developed the first methods for laser cooling and trapping of molecules. These techniques will enable interesting new frontiers in quantum many-body physics and quantum chemistry, as well as next-generation EDM searches. Host: Cheng Chin, 2-7192 or via email to cchin@jfi.uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The 1st Tuesday JFI Colloquium

October 2, 2018
GCIS W301 | Tuesday, 4:00 pm

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Tobias Walther, PhD, Harvard

The Phase of Fat: Mechanisms & Physiology of Lipid Storage


Biophysical Dynamics

October 2, 2018
GCIS W301 | Tuesday, 12:00 pm

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Stuck Inside a Protein With the Deformation Blues Again

Noon is when we eat and laugh and talk
12:15 is when the subject is revealed
MRSEC Baglunch

September 28, 2018
GCIS E123 | Friday, 12:00 pm

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Dr. Quentin Ficheux, Ecole Normale Superieure

Dynamics of a Qubit while Simultaneously Monitoring its Relaxation and Dephasing

Measuring a spin-1/2 along one direction projectively maximally randomizes the outcome of a following measurement along a perpendicular direction. Here, using either projective or weak measurements, we explore the dynamics of a superconducting qubit for which we measure simultaneously the three components x, y and z of the Bloch vector.

The x and y components are obtained by measuring the two quadratures of the fluorescence field emitted by the qubit. Conversely the z component is accessed by probing an off-resonant cavity dispersively coupled to the qubit. The frequency of the cavity depends on the energy of the qubit and the strength of this last measurement can be tuned from weak to strong in situ by varying the power of the probe.
In this experiment, the tracked system state diffuses inside the Bloch sphere and performs a random walk whose steps obey specific rules revealing the backaction of incompatible quantum measurements. The associated quantum trajectories follow a variety of dynamics ranging from diffusion to Zeno blockade. Their peculiar dynamics highlight the non trivial interplay between the backaction of the two aforementioned incompatible measurements.
JFI Special Seminar

September 27, 2018
GCIS E123 | Thursday, 11:00 am

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Frontiers of Molecular Engineering

Join us in Chicago to discover how molecular engineering approaches are driving significant breakthroughs across a broad range of research disciplines and applications, from batteries to biotechnology, and learn of the key challenges for the future. Attendees will be exposed to the current state of the art across diverse areas of research, with an emphasis on the development of an interdisciplinary approach.

This two-day symposium is supported by Molecular Systems Design & Engineering, The Institution of Chemical Engineers (IChemE), the National Science Foundation (NSF), and the Institute for Molecular Engineering at the University of Chicago.

The programme will feature invited speakers plus a poster session.

Topics will include:

Energy storage and conversion
Biotechnology
Computational material design
Capture and separations technologies
Assembly of soft and biological materials
Catalysis
Machine learning and data science in material design
Molecular Engineering

September 27, 2018
ERC 161 | Thursday, 9:00 am

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Lorenz Eberhardt, ETH

Holography on AdS3xS3xS3xS1 and stringy AdS3 spectra

The purpose of the talk is twofold. I will first report on progress made on the problem of finding a holographic dual of the large N=4 background AdS3xS3xS3xS1. I will discuss the BPS spectrum of the background in detail, both from a string theory and a supergravity point of view. This allows us to make a proposal for the CFT dual, at least for specific values of the fluxes.
In a second part of the talk, I will discuss the string theory spectrum on AdS3 backgrounds away from the pure NS-NS flux point, where a WZW description of the worldsheet theory exists. The theory with R-R flux can be described in the hybrid formalism by a sigma-model on a supergroup coupled to ghosts. I will explain how to solve this sigma-model in the plane-wave limit and reproduce the plane-wave spectrum from the hybrid formalism
Theory Seminar

September 26, 2018
PRC 201 | Wednesday, 1:30 pm

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Professor Yoon-Young Kim, Seoul National University

Total Longitudinal-Transverse Mode Conversion through Anisotropic Elastic Metamaterials

Professor Yan Yoon’s research is focused on elastic metamaterials and mechanics-based design and optimization. His research has been recognized with many awards including, most recent awards, Seoul National University Award for Academic Excellence (2017), KSCM (Korean Society for Computational Mechanics) Computational Mechanics Award (2017), APACM (Asian-Pacific Association for Computational Mechanics) Award for Computational Mechanics (2016), and ASSMO (Asian Society for Structural and Multidisciplinary Optimization) Award (2016). He has also given a number of keynote/plenary lectures in international conferences, including recent plenary lectures at the World Congress of Computational Mechanics (2016), World Congress of Structural and Multidisciplinary Optimization (2017) and the International Conference on Emerging Technologies in Mechanical Engineering (2018).



Elastic waves in solids carry both longitudinal and transverse waves. The particle motions in the longitudinal and transvere modes take place along the parallel and perpendicular directions to the direction of propagation, respectively. Their propagation speeds are also different due to the difference in their impedances. Therefore, no longitudinal (transverse) mode can be totally converted to the transverse (longitudional) mode unless the wave propagation direction is allowed to alter. Here, we show that the unidirectional total mode conversion from the longitudinal mode to the transvese mode (and vise versa) is possible if our elaborately designed anisotropic metamaterial converter is used. As a critical application of the discovered phenomenon of total mode conversion that is enabled by a metamaterial, we will present new-generation ‘ultrasonic non-invasive flow sensors’ that clamp to the outside of a fluid-flowing pipe. We will show how the new sensors can overcome the technical limiations of currently available flow sensors.



Prof. Yoon led the National Creative Research Initiatives Centers designated by the Korean Ministry of Science and Technology from 2002 to 2011. He was the President of the KSME (Korean Society of Mechanical Engineers) and is the President of the KSCM (Korean Society for Computational Mechanics). He is also a Vice-President of the ISSMO (International Society of Structural and Multidisciplinary Optimization) and the President of the ASSMO (Asian Society of Structural and Multidisciplinary Optimization). He (has) served as editors in several international journals. He is a member of KAST (Korean Academy of Science and Technology) and a member of NAEK (National Academy of Engineering), Korea. He also works as advisory professors for Samsung Electronics, Samsung Advanced Institute of Technology, and SEMES. He also (has) served as an international board member of KTH (Royal Institute of Technology, Sweden), an external review member of University of Tokyo, RACE, and a foreign review member of Beijing Institute of Technology, the Mechanics Program.
JFI Special Seminar

September 25, 2018
GCIS E123 | Tuesday, 4:00 pm

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David McGady, Niels Bohr International Academy

Path integrals, finite temperature, and lattices

Surprisingly, partition functions for some model systems in statistical mechanics are invariant under formally reflecting the sign of temperature, T: +T -> -T. We call this T-reflection invariance. Clearly, partition functions for generic statistical systems cannot be invariant under T-reflection. However, in this talk we focus on finite-temperature path integrals and give a general picture for why finite-temperature path integrals in quantum field theory *should* behave well under T-reflection. We probe this general picture in the context of the harmonic oscillators (in one-dimension) and in conformal field theories on the two-torus (in two-dimensions) and in the mathematics of modular forms. We find that the relevant path integrals are often invariant only up to overall T-independent phases, which could be naturally interpreted as new anomalies under large coordinate transforms.
Kadanoff Seminar

September 25, 2018
PRC 201 | Tuesday, 12:00 pm

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Special Seminar: Professor Thomas Teets, University of Houston

Synthetic Strategies to Optimize Photophysical and Photoredox Properties of Organometallic Complexes

This talk describes complementary synthetic approaches to control and enhance the excited-state properties of organometallic complexes. Bis-cyclometalated iridium complexes have emerged as champion compounds in a number of applications requiring efficient phosphorescence and excited-state redox chemistry. Outstanding challenges include the design of compounds with efficient, stable blue luminescence, and overcoming the typically poor photoluminescence quantum yields of red to near-infrared-emitting complexes. Our efforts have resulted in new designs for robust blue-emitting complexes, using strongly σ-donating acyclic diaminocarbene supporting ligands. These complexes are prepared by unconventional routes relying on the electrophilic reactivity of coordinated isocyanides. In a separate effort, we have employed nitrogen-containing, π-donating ancillary ligands in the development of new bis-cyclometalated iridium complexes which are efficient red and near-infrared phosphors or potent photoreductants. And finally, a more recent thrust in our group has produced a modular self-assembly strategy to prepare multi-chromophore arrays featuring cyclometalated iridium, providing easy access to a class of supramolecular constructs which are rich platforms for studying fundamental aspects of excited-state dynamics and may function as ratiometric environmental sensors.
Chemistry

September 20, 2018
GCIS W301 | Thursday, 1:00 pm

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Anomalous subdiffusion of highly-charged, membrane-covered nanoparticles

munch bites: 12:00
Crunch bytes: 12:15
MRSEC Baglunch

September 14, 2018
GCIS E123 | Friday, 12:00 pm

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Mind the gap: Fluctuations as a mechanism for thickness selection

Eat at noon. Talk at 12:15
MRSEC Baglunch

August 31, 2018
GCIS E123 | Friday, 12:00 pm

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My simulated discontinuous shear thickening---a first-order transition?

Eat: noon
Delve: 12:15
MRSEC Baglunch

August 24, 2018
GCIS E123 | Friday, 12:00 pm

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Closs Lecture: Professor Jin-Quan Yu, The Scripps Research Institute

Enantioselective and Remote C-H Activation Reactions


Chemistry

August 13, 2018
Kent 120 | Monday, 4:00 pm

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Professor Yu Zhao, National University of Singapore

Catalytic Enantioselective Redox-Neutral Processes for Efficient Chemical Synthesis

The development of economical and selective catalytic processes is essential for the promotion of sustainable chemical synthesis. My research group at National University of Singapore focuses our efforts on the development of catalytic enantioselective redox-neutral transformations to access valuable chiral building blocks in organic synthesis. Such methods have the significant advantage of circumventing the redundant oxidation/reduction steps to reduce waste production in chemical synthesis. In particular, the stereo-convergent preparation of chiral amines and N-heterocycles from readily available racemic alcohols through borrowing hydrogen, and new processes of enantioselective isomerization of alkenyl alcohols will be discussed in details.
Chemistry

July 30, 2018
Kent 120 | Monday, 4:00 pm

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Bacteria communication on a glowing film?

Eat: 12:00
Meet: 12:15
MRSEC Baglunch

July 27, 2018
GCIS E123 | Friday, 12:00 pm

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We learn from papers, but what can paper learn?

Meet, eat 12:00
Brainy meat 12:15
MRSEC Baglunch

July 20, 2018
GCIS E123 | Friday, 12:00 pm

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NAMBU,FANO AND MY FIRST MARCH MEETING ABSTRACT

by regular participant James E. Clark

Bring food at 12:00
Talk begins at 12:15
MRSEC Baglunch

July 13, 2018
GCIS E123 | Friday, 12:00 pm

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Tuan Tran, Nanyang Technological University

Critical conditions for jumping of electrowetting droplets

A droplet resting on a solid surface stretches further with an applied electric field. Turning off the field, the droplet pulls back to its initial state and may jump up from the surface against gravitational force. In this study, we ask and attempt to answer a simple question: What is the condition for such droplets to detach from the surface? We found that the key factors of jumping condition include the friction and pinning effect at the contact line. The friction at the contact line is responsible for most of the viscous dissipation, while contact line pinning acts as an energy barrier to prevent detachment. We propose a simplified model capturing these effects in the jumping condition and provide an experimental validation to the model. The results highlight the crucial role of contact line dynamics in dynamical wetting phenomena.
Computations in Science

July 11, 2018
KPTC 206 | Wednesday, 12:30 pm

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Dr. Abhinendra Singh, City College of New York

Towards a General Constitutive Model of Dense Frictional Suspensions

The mechanism of shear thickening in dense suspensions has been shown to be consistent with a transition from lubricated rheology, where close interactions between suspended particles take place through a thin liquid film, to a frictional rheology, wherein particles experience frictional contacts. Particle simulations that led to this concept have been successful in quantitatively reproducing the non-Newtonian shear behavior of discontinuous shear thickening suspensions [1].



As a step towards developing a constitutive model for such materials, we extend the method presented by Wyart-Cates [2] for lubricated and frictional rheologies that is applicable to both shear and normal stresses for non-colloidal suspensions and demonstrate the agreement between such a model and the simulation results [3]. Through this approach we develop a flow-state map of this material.



The challenge of extension of this framework for constitutive modeling of colloidal suspensions remains. In order to guide the efforts to tackle this challenge, we examine the role of cohesive forces on the shear rheology of colloidal suspensions. This is achieved through the inclusion of interparticle repulsive and cohesive forces in addition to hydrodynamic and frictional forces that have been present in our particle simulations [4]. These simulations at low to intermediate strength of cohesion show yield stress at low stress, followed by shear thinning and eventual shear thickening at high values of stress. For high strength of cohesion shear thickening is obscured. Including the details about yield stress and shear thinning, an extension to the shear thickening model to cohesive non-Brownian dense frictional suspension is proposed.


JFI / IME Seminar

June 25, 2018
ERC 201 | Monday, 12:00 pm

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cell networks that won't make your skin crawl

Bring food 12:00
Listen 12:15
MRSEC Baglunch

June 22, 2018
GCIS E123 | Friday, 12:00 pm

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Eun-Gook Moon, KAIST, Korea

Topological defects and phase transitions in 2D correlated systems

The Landau paradigm of phase transitions is one of the backbones in critical phenomena. With a Z2 symmetry, it describes the Ising universality class whose central charge is one half (c = 1/2) in two spatial dimensions (2D). Motivated by recent experiments in strongly correlated systems, which show possibilities beyond the Landau paradigm, we propose an exotic universality class of a Z2symmetry breaking transition with c=1. We argue that controlling topological defects may realize the exotic class. In addition to novel critical exponents, we find that the onset of an order parameter may be super-linear in contrast to the sub-linear onset of the Ising class. We argue that a super-linear onset of a Z2 order parameter without breaking a bigger symmetry than Z2 is evidence of exotic phenomena, and our results are applied to recent experiments in phase transitions at pseudo-gap temperatures. If time allows, we discuss topological phase transitions in Kitaev quanatum spin liquids and their signals
Kadanoff Seminar

June 21, 2018
PRC 201 | Thursday, 1:30 pm

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Professor Kazuaki Ishihara, Nagoya University

Rational Design of High Performance Catalysts on Acid-Base Combination Chemistry


Chemistry

June 15, 2018
Kent 120 | Friday, 1:15 pm

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You CAN teach an old foam new tricks

come and see how

12:00 the seance, with eating
12:15 the main event
MRSEC Baglunch

June 15, 2018
GCIS E123 | Friday, 12:00 pm

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2018 Science@theInterface Symposium

Microscopy: Advances and Applications

Session 1
10:30-11:30 Joerg Bewersdorf, PhD, Yale University
3D and Multicolor Live-cell Super-resolution Microscopy for Cell Biological Research

11:30-12:00 Marco Allodi, PhD, University of Chicago
Optical Resonance Imaging: an Optical Analog to MRI for Widefield Ultrafast Imaging

12:00-12:45 lunch

Session 2
12:45-1:45 Sara Abrahamsson, PhD, University of California, Santa Cruz
Multi-Focus SIM development for studying transcription and chromatin dynamics

1:45-2:45 Aydogan Ozcan, PhD, University of California, Los Angeles
Deep Learning-enabled Computational Imaging

2:45-3:00 break

Session 3
3:00- 3:30 Xiaolei Wang, PhD, University of Chicago
3D single insulin granule tracking reveals anisotropic dynamics in Beta cells

3:30-4:30 Fei Chen, PhD, Broad Institute
From cells to tissues: Tools for understanding in situ tissue organization
Biophysical Dynamics

June 15, 2018
BSLC 109 | Friday, 10:30 am

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JFI Presents - "Women in Chemistry" -Francesca Serra, John Hopkins University

Liquid Crystals for Self-Assembly

Soft materials are a promising tool to explore controllable energy landscapes. Liquid crystals, in particular, combine reconfigurability, unique optical properties and the possibility of directing their self-assembly via the bounding surfaces. These fluids with long-range orientational order possess elastic energy and can generate topological defects, two useful tools for assembly. I will show two examples of interplay between liquid crystal confinement and control of assembly. In one setting, microparticles can be precisely directed to desired locations by modulating the orientation of nematic liquid crystals using topography. An undulated boundary generates small elastic distortions in liquid crystals that can precisely direct the motion of colloidal particles and induce a transformation of the topological defect associated to the particle. In my second example, an array of topological defects in nematic liquid crystals is generated by applying an electric field and it is made regular by appropriate patterning of the electrodes. The defect array can thus form a square lattice of defects, regular over several millimeters, and ideal to create tunable optical gratings. For further information please contact the Host, Sara Zinn via email at szinn@uchicago.edu. Persons who has a disability and may need assistance please contact Brenda Thomas at 2-7156 or bthomas@uchicago.edu. Hosted by Women in Chemistry (WIC)
Funded in Part by Student Government
JFI Special Seminar

June 12, 2018
GCIS W301 | Tuesday, 4:00 pm

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Stephanie Palmer, The University of Chicago


Physics Colloquium

June 8, 2018
KPTC 106 | Friday, 2:30 pm

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Driving creepy repulsive flow

(with movies)

Eat 12:00 (before movies)
Talk 12:15
MRSEC Baglunch

June 8, 2018
GCIS E123 | Friday, 12:00 pm

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Prof. Zhi Ping (Gordon) Xu, University of Queensland

Tailoring Inorganic Nanoparticles for Efficient Cancer Therapy and Imaging

I will first introduce two types of inorganic nanoparticles, i.e. layered double hydroxide (LDH) and lipid-coated calcium phosphate (LCP) nanoparticles, and then demonstrate their high potential as the drug/gene delivery platforms. I will present a few examples to show efficient co-delivery of functional small interfering RNA (siRNA) and anti-cancer drug to cancer cells for the synergic inhibition. I will also talk about our recent results for target delivery of siRNA to treat cancers.

In the second part, I will present our recent research using clay nanoparticles as vaccine adjuvants to promote higher and long-term immune responses against cancer and bacteria. We have noted that LDH is able to readily load model antigen ovalbumin (OVA) and the toll-like receptor ligand CpG together, promote higher levels of specific antibodies, and modulate the immune response from Th2 bias towards the preferred polarity Th1 for anti-cancer purpose. We have found that LDH and hectorite (HEC) nanoparticles as adjuvants to promote stronger and long-lasting immune responses against the infectious bacteria.

In the final part, I will demonstrate the capability of inorganic nanoparticles as positron emission tomography (PET) and magnetic resonance imaging (MRI) contrast agents for cancer imaging and detection.
Chemistry

June 7, 2018
GCIS 500B | Thursday, 4:00 pm

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Andrei Tokmakoff, University of Chicago

The Ultrafast Structural Dynamics of Protons in Liquid Water

As omnipresent as liquid water is, we still struggle to understand its chemistry at a molecular scale. It is not just a solvent but its rapidly
changing network of hydrogen bonds shapes and changes solutes within it. The conceptual and technical challenges of studying such problems are nowhere more apparent than when investigating the transport of an excess proton in water, since it is only distinguishable as an excess charge imbedded in the liquid. Proton transfer in water has long been attributed to a sequential displacement of protons along a chain of hydrogen bonds, but there is little experimental evidence to describe the solvation structure of this charge defect and how it changes in charge transfer. I will describe research being performed to visualize the molecular dynamics of excess protons in liquid water using new techniques in ultrafast 2D IR spectroscopy.
Molecular Engineering

June 7, 2018
ERC 201 | Thursday, 11:00 am

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Raghu Mahajan, IAS, Princeton

The Conformal Bootstrap at Finite Temperature


Kadanoff Seminar

June 4, 2018
PRC 201 | Monday, 1:30 pm

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Dr. Reatha Clark King

Distinguished Alumna Lecture

Dr. Reatha Clark King received her early education in a one-room schoolhouse at Mt. Zion Baptist Church. After graduating as valedictorian of Moultrie High School for Negro Youth, she attended Clark College in Atlanta on scholarship, where she earned a double BS in chemistry and mathematics. A Woodrow Wilson Fellowship brought her to the University of Chicago for her MS in Chemistry, which she obtained in 1960. She remained for her PhD under Ole Kleppa, graduating in 1963 with a thesis titled “Contributions to the Thermochemistry of the Laves Phases.” Dr. King then became the first female African American research chemist at the National Bureau of Standards, where she won the Meritorious Publication Award for a paper on fluoride flame calorimetry. In 1968, Dr. King joined York College (CUNY) as a faculty member, eventually becoming associate dean for the Division of Natural Science and Mathematics and associate dean for academic affairs. She earned an MBA from Columbia College during a sabbatical. In 1977, Dr. King became president of Metropolitan State University in Minneapolis. Her eleven-year tenure in this position is remembered for substantial expansion of the college, as well as increased recruitment of women and minorities. Following a stellar career in research and academia, Dr. King spent the next fourteen years in industry as vice president of General Mills Corporation and President/Executive Director of General Mills Foundation. She has served on the boards of several corporations and nonprofit organizations, including Exxon Mobil, H. B. Fuller, Wells Fargo, Allina Health Systems, and American Council on Education, and has been a trustee of Clark Atlanta University, Carleton College, and the University of Chicago. She has received many awards, including the Defender of Democracy Award from the Martin Luther King, Jr. National Memorial Project Foundation, National Association of Corporate Directors Director of the Year, Exceptional Black Scientist Award from CIBA-GEIGY, International Citizen Award from the International Leadership Institute, Louis W. Hill, Jr. Fellowship in Philanthropy, and Ebony Magazine’s Top 50 Black Executives in Corporate America. She has been inducted into the Delta Sigma Theta sorority for public service and recognized with 14 honorary doctorate degrees.
Chemistry

June 1, 2018
GCIS W301 | Friday, 3:30 pm

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Thomas Faulkner, The University of Illinois, Urbana-Champaign

Why is negative energy density bad, and how does quantum information constrain it

Negative energy density can arise naturally in Quantum Field Theory, the theoretical framework with which we describe fundamental particle physics and the matter which makes up our universe. However too much negative energy density can lead to pathologies when considering the dynamics of spacetime in which this matter resides. This dynamics is governed by Einstein’s equations which relates such energy densities to the curvature of spacetime. In this talk I will discuss conjectured bounds on negative energy density and sketch very recent general proofs of these bounds. The methods we use combine causality considerations with concepts taken from the study of quantum information.
Physics Colloquium

May 31, 2018
KPTC 106 | Thursday, 4:00 pm

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The Tuesday JFI Seminar - Prof. Yan Yu, Department of Chemistry, Indiana University

Spatially Organizing Biointerfaces to Interrogate Immune Functions

The immune system functions on the basis of intricately organized chemical reactions and physical forces. Examples range from the engulfment of invading bacteria that relies on a fine balance of competing mechanical forces, to the activation of T-lymphocytes that requires collective interactions between thousands of receptors at the junction between cells. Owing to the complexity of these processes, understanding immune functions using traditional biological tools is highly challenging. In this talk, I will present my group’s research progress towards designing unique biointerfaces to enable the quantitative understanding and manipulation of immune functions. Our research so far has capitalized on Janus particles, which, like the two-faced Roman god Janus, are made chemically, biologically, optically or magnetically asymmetric. We developed Janus particle-based toolsets for measuring cell dynamics in multi-dimensions beyond translational motion and for spatiotemporally controlling cell functions. Using these methods, we uncovered new dynamics and mechanisms in immune processes, from phagocytosis to intracellular trafficking, which would otherwise be difficult to access with traditional means. For further information please contact Brenda Thomas at 773-702-7156 or via email at bthomas@uchicago.edu. You may also contact the Host, Bozhi Tian at 773-702-8749 or via email to btian@uchicago.edu.
The Tuesday JFI Seminar

May 29, 2018
GCIS W301 | Tuesday, 4:00 pm

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The Academic Job Market

MRSEC presents: A Mini Workshop

Presentation: 10:00 a.m. - 10:45 a.m.
Short break
Faculty Panel: 10:45 a.m. - 11:30 a.m.
MRSEC Workshop

May 29, 2018
GCIS W301 | Tuesday, 10:00 am

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Grayson L. Jackson, University of Minnesota

Nanoconfined Water and Water-mediated Ion Transport in Model Membrane Materials

The ill-defined pore morphologies and connectivities of conventional membrane materials have hampered a clear understanding of the relationship between pore geometry, pore interfacial chemistry, and ultimate membrane performance. Derived from the self-assembly of ionic amphiphiles in concentrated aqueous media, lyotropic liquid crystals (LLCs) are a well-defined materials platform for uncovering these fundamental membrane structure-property relationships due to their monodisperse, sub-3 nm pores decorated with amphiphile headgroup chemical functionalities (Figure 1). Beyond fundamental studies, network (N) phase LLCs are coveted for membrane applications by virtue of their co-continuous aqueous and hydrocarbon domains, yet their non-constant mean curvature interfaces limit their thermodynamic stabilities. In this presentation, I will describe our efforts to understand how pore diameter and interfacial curvature (concave or convex) affects H+ transport in LLCs formed by sulfonate amphiphiles, which unexpectedly reveal that convex nanopores have significantly higher H+ conductivities. Complementary quasielastic neutron scattering (QENS) studies of the confined water dynamics in LLCs with convex nanopores indicate that water diffusion depends sensitively on nanopore geometry and interfacial esults suggest that proton exchange membranes (PEMs) with convex nanopores may exhibit enhanced performances.

JFI Special Seminar

May 25, 2018
GCIS E223 | Friday, 3:00 pm

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Christopher Uyeda, Purdue University

Catalysis at Metal–Metal Bonds

The discovery of new catalysts is central to the pursuit of more efficient and sustainable processes in organic synthesis. Whereas mononuclear transition metal complexes have been widely utilized in reaction methodology, the scope of both stoichiometric and catalytic processes for complexes of higher nuclearity is comparatively limited. In principle, multinuclear complexes might engage in unprecedented modes of reactivity by binding substrates or engaging in redox processes that span multiple metal centers. New classes of catalysts that can capitalize on these cooperativity effects have the potential to exhibit activity or selectivity profiles that complement or surpass existing mononuclear systems.
Our group has been developing new platforms that support coordinatively unsaturated and reactive metal–metal bonds. In pursuit of this goal, we have developed a naphthyridine–diimine ligand that was used to prepare dinuclear complexes of mid-to-late first-row transition metals. The redox-active nature of these ligands imparts rich redox chemistry to these complexes, enabling an array of multielectron oxidation and reduction reactions. The applications of these complexes to catalytic processes relevant to organic synthesis will be presented.
Persons with a disability may call (773) 702-0388 in advance for assistance.
Chemistry

May 25, 2018
Kent 120 | Friday, 1:15 pm

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Rudolf Grimm, The University of Innsbruck

Impurities in an ultracold Fermi sea: Quasiparticles, phase separation, and more

Impurity physics has emerged as a new branch of research in the field of atomic quantum gases. A central feature is the wide tunability of interactions between the impurities and the surrounding medium. By using magnetically controlled Feshbach resonances, regimes of strong interactions can be reached, which reveal intriguing many-body physics. After a general introduction into the field, I will present our experiments on fermionic and bosonic potassium impurities immersed in a deeply degenerate Fermi sea of lithium atoms. For fermionic impurities, we study the spectrum of quasiparticle excitations and the regime where the Fermi-liquid picture breaks down. Moreover, we observe the formation dynamics of quasiparticles in real time. For bosonic impurities, we observe small-sized Bose-Einstein condensates and, for strong repulsive interactions, their phase separation from the Fermi sea. If time permits, I will also introduce a new quantum gas mixture (dysprosium and potassium) with great prospects for future research on fermionic quantum gases.
Physics Colloquium

May 24, 2018
KPTC 106 | Thursday, 4:00 pm

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Charles M. Lieber, Harvard University

Nanoelectronic Tools for Brain Science

Nanoscale materials enable unique opportunities at the interface between the physical and life sciences, for example, by integrating nanoelectronic devices with cells and/or tissue to make possible bidirectional communication at the length scales relevant to biological function. In this presentation, I will overview a new paradigm for seamlessly merging nanoelectronic arrays and circuits with the brain in three-dimensions (3D). First, the design consideration of matching structural, mechanical and topological characteristics of neural probes and brain tissue will be discussed, thus leading to the new concept of tissue-like mesh electronics. Second, quantitative time-dependent histology studies demonstrating the absence of a tissue immune response on at least a year time-scale, as well as interpenetration of neurons and neurofilaments through the open mesh electronics structures will be presented. Third, uniquely, stable electrophysiology data demonstrating the capability to track and stably record from the will describe several current directions of research, including studies that push the limits of the mesh design paradigm and work focused on fundamental brain science problems, including aging and vision. Finally, the opportunities for future developments will be discussed.
Chemistry

May 24, 2018
GCIS W301 | Thursday, 4:00 pm

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Louise Berben, University of California, Davis

Redox Chemistry of Al(III) Metal-Ligand Complexes

In this talk I will describe the chemistry of Group 13 metal complexes with redox-active ligands. The synthesis and characterisation of iminopyridine and bis(imino)pyridine complexes of Al(III), Ga(III) and In(III) will be described along with a presentation of their structural and electronic properties. Bis(ligand) complexes of Al, Ga and In are each shown to undergo five reversible electron transfer events and each of the charge states have been structurally characterized. Using techniques including EPR and NIR spectroscopy, we characterized the mixed-valent states for each complex and characterize them as Class III, fully delocalized (Al), and Class II/III (Ga and In). The lowered electronic coupling in complexes of the heavier Group 13 elements arises from involvement of a three-state MV system where the unpaired electron spends more time on the Group 13 ion. The reactivity of the Al complexes will also be discussed in detail, including the mechanisms for ligand-based proton transfer that mediate the activation of polar bonds such as those in alcohols and amines. Dehydrogenation reactions are initiated by the bond activation reactions and these include the conversion of formic acid into CO2 and H2 and the conversion of benzylamine into imine with loss of H2 and NH3. Ligand-based proton and electron transfer is also promoted by various redox active ligands supported by Al. Control of the electrocatalytic mechanism for H2 evolution, based on ligand design, will be described.
Chemistry

May 24, 2018
Kent 120 | Thursday, 1:00 pm

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Niall M. Mangan, Northwestern University

Identification of Hybrid Dynamical Systems via Clustering and Sparse Regression

Inferring the structure and dynamical interactions of complex systems is critical to understanding and controlling their behavior. Hybrid systems are challenging to identify because the parameters and equation structure may change across multiple dynamical regimes. Key examples include varying transmission rates in epidemiological problems and legged locomotion. Many current methods focus on inferring a model for the system and detecting switching points in a time-centric framework. One can reframe the problem by clustering in data-driven coordinates, such that similar dynamical behavior is close together, and then use the sparse identification of nonlinear dynamics (SINDy) method to identify different dynamical regimes. I will discuss model selection using SINDy and information criteria. I will then demonstrate the success of the method hybrid-SINDy on a spring-mass model and a simple infectious disease model with time-dependent transmission rates. I will also investigate robustness to noise and cluster-size.
Computations in Science

May 23, 2018
KPTC 206 | Wednesday, 12:15 pm

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Debanjan Chowdhury, MIT

Towards a universal description of non-Fermi liquid metals with critical Fermi surfaces

Numerous strongly correlated materials display non-Fermi liquid properties over a broad range of temperatures. One of the remarkable features observed in many of these systems is the apparent universality of the phenomenology, in spite of the completely distinct microscopic details. Inspired by the rich phenomenology of such non-Fermi liquids, I will construct examples of translationally invariant solvable models of metals, composed of lattices of Sachdev-Ye-Kitaev dots with identical local interactions. These models display crossovers as a function of temperature into regimes with local quantum criticality and non-Fermi liquid behavior. I will show the existence of sharply defined critical Fermi-surfaces in the non-Fermi liquid regime, that give rise to quantum oscillations in the magnetization as a function of an external magnetic field, in the absence of quasiparticle excitations. I will discuss the implications of these results for fundamental bounds on relaxation rates and speculate on possible coarse grained descriptions of a class of intermediate scale non-fermi liquid behavior in generic correlated metals.
Kadanoff Seminar

May 22, 2018
PRC 201 | Tuesday, 1:30 pm

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Stefano di Talia, PhD, Duke Medical Center

Cell cycle synchronization in development and regeneration


Biophysical Dynamics

May 22, 2018
GCIS W301 | Tuesday, 12:30 pm

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Valeria Molinero, Univesity of Utah

ce formation in the atmosphere: a molecular perspective

Crystallization of water in clouds is critical for precipitation and to determine the radiative properties of the atmosphere. Despite decades of research, there are still significant uncertainties in the prediction of the rates of ice nucleation, and about what is the structure of the ice crystals that form under different atmospheric conditions. In this presentation I will discuss our work using molecular simulations and theory to elucidate the microscopic pathways of ice formation, the structure and interfaces of atmospheric ices, and the role of soluble molecules, surfaces, and pores on controlling the rates and mechanisms of ice nucleation.
Molecular Engineering

May 22, 2018
ERC 201B | Tuesday, 11:00 am

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Harry Gray, Caltech

Living with Oxygen

High-valent iron-oxos are intermediates in biological reactions critical to life on earth, notably including oxygen reduction to water by cytochrome oxidase and steroid oxygenation by cytochrome p450. Jay winkler and i recently discovered that oxygenases and other enzymes that require oxygen for function have chains of tryptophans and tyrosines that extend from active-site regions to protein surfaces. We think it likely that hole tunneling through these trp/tyr chains protects redox enzymes from oxidative destruction.
Chemistry

May 21, 2018
Kent 120 | Monday, 4:00 pm

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Sergei Moroz, Technical University Munich

Effective field theory of a vortex lattice in a bosonic superfluid

Using boson-vortex duality, we formulate a low-energy effective theory of a two-dimensional vortex lattice in a bosonic Galilean-invariant compressible superfluid. The excitation spectrum contains a gapped Kohn mode and an elliptically polarized Tkachenko mode that has quadratic dispersion relation at low momenta. External rotation breaks parity and time-reversal symmetries and gives rise to Hall responses. We extract the particle number current and stress tensor linear responses and investigate the relations between them that follow from Galilean symmetry. We argue that elementary particles and vortices do not couple to the spin connection which suggests that the Hall viscosity at zero frequency and momentum vanishes in a vortex lattice.
Kadanoff Seminar

May 21, 2018
PRC 201 | Monday, 1:30 pm

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Mark Lautens, University of Toronto

Improving Efficiency Through Catalytic and Multicatalytic Reactions

Oxidative addition and reductive elimination are two fundamental steps common to many different catalytic reactions. Insertion into C-X bonds is particularly prevalent as one of the first steps in a catalytic cycle.
We have been exploring the synthetic potential associated with reversible oxidative addition into carbon-halogen bond and recently developed a palladium catalyzed carboiodination reaction.1 This lecture will describe the scope and limitations of the reaction including recent work that has expanded the scope. 2-3
We have also been exploring the value of combining catalysts and substrates in a multicomponent multicatalyst strategy (MC)2R.4 Recent advances will be presented.
C-H Functionalization remains one of the most active areas of research in organic chemistry.5 We will present our recent advances in this field.
Chemistry

May 18, 2018
Kent 120 | Friday, 1:15 pm

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What stops my heavy fluid film from from falling?

12:00 time to eat
12:15 time to ponder
MRSEC Baglunch

May 18, 2018
GCIS E123 | Friday, 12:00 pm

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Michel Devoret, Yale University

Catching and Reversing a Quantum Jump Mid-flight

The basic phenomenon of quantum jumps between two states of a system driven by a deterministic force while undergoing continuous monitoring is exploited in precision quantum measurements and plays a key role in our fundamental understanding of open quantum systems. Quantum jumps are emblematic of the special nature of randomness in quantum theory. Although it had been argued in the past that their nature is discontinuous, modern measurement theory stipulates that the state of the system evolves continuously during a jump. Even more remakable, in the case of a system possessing at least 3 states, it was shown theoretically that it is possible i) to obtain an advance warning that the jump is about to occur, and consequently ii) to reverse it if was initiated by a coherent drive. We have successfully implemented the indirect QND measurement of a superconducting artificial atom transition from its ground state G to a dark state D by monitoring the occupancy of an auxiliary bright level B connected to G by a Rabi drive. By conditioning the tomography and manipulation of the G-D manifold on the non-occupancy of the B level for a deterministic duration, we catch and even reverse the jump (1). Our experimental results, in agreement with the predictions of quantum trajectories theory with essentially no adjustable parameters, supports the point of view that a single system under continuous, efficient observation can have a time-dependent wavefunction inferred from the record of previous measurements. [1] Z. Minev, S.O. Mundhada, S. Shankar, P. Reinhold, R. Guttierez, R.J. Schoelkopf, M. Mirrahimi, H. Carmichael, M.H. Devoret (2017).
Physics Colloquium

May 17, 2018
KPTC 106 | Thursday, 4:00 pm

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Professor Michael L. Neidig, University of Rochester

Intermediates and Mechanism in Iron-Catalyzed Cross-Coupling

Despite the increasing development of iron-based catalysts for organic synthesis, a detailed molecular level understanding of these systems has remained largely elusive. This limitation is in stark contrast to palladium chemistry, where detailed studies of active catalyst structure and mechanism have provided the foundation for the continued design and development of catalysts with novel and/or improved catalytic performance. The use of an experimental approach combining advanced inorganic spectroscopies (Mössbauer, magnetic circular dichroism, electron paramagnetic resonance), density functional theory studies, synthesis and kinetic analyses enables the direct evaluation of the active iron species and insight into the mechanisms of catalysis in iron-catalyzed reactions in organic synthesis, including iron-catalyzed cross-coupling. Previous studies from our group using this approach have established the active iron species in iron-bisphosphine catalyzed cross-coupling of mesityl Grignard reagents and primary alkyl halides1 as well as phenyl nucleophiles and secondary alkyl halides.2 Of particular interest are iron-catalyzed cross-couplings with simple ferric salts where we have previously reported the isolation and characterization of [MgCl(THF)5][FeMe4], an intermediate in the reduction pathway of simple ferric salts with methylmagnesium bromide.3 This presentation will focus on recent studies, including the isolation, characterization and reactivity of iron-ate species of relevance to cross-coupling such as [MgCl(THF)5][Fe8Me12],4 as well as recent developments in systems combining iron salts and ligand additives.
Chemistry

May 17, 2018
GCIS W301 | Thursday, 1:00 pm

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Douglas Tobias, University of California - Irvine

Protein Hydration Water

Proteins present rough, chemically heterogeneous and dynamic surfaces to their surrounding solvent, which for many proteins is primarily aqueous. Roughly a monolayer of water, the so-called "hydration water", is perturbed structurally and dynamically by interaction with a protein molecule. I will present results from experimental and molecular dynamics simulation studies that exemplify the anomalous properties of protein hydration water and reveal differences in the behavior of water near folded soluble proteins, intrinsically disordered proteins, and membrane proteins. Hydration water is crucial for protein function. I will also present both experimental and simulation results that elucidate the mechanism by which functionally important protein motions are coupled to water dynamics. Finally, I will discuss teh nature and range of protein-water collective fluctuations, and the similarities and differences between the dynamics of protein-confined water at ambient temperature and bulk water at low temperature.
Molecular Engineering

May 17, 2018
ERC 201 | Thursday, 11:00 am

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Ariel Amir, Harvard

From single-cell variability and correlations across lineages to the population growth

Cells of all domains of life must coordinate their cell cycle meticulously in order for protein levels, cell size and DNA replication to be appropriately regulated and to be able to prevent stochastic fluctuations from accumulating over time. These control mechanisms will lead to correlations in various cellular traits across the lineage tree (notably, size and generation times). I will present a recent model we developed for understanding cellular homeostasis and characterizing these correlations and fluctuations. I will discuss the implications of these correlated fluctuations on the population growth. In contrast to the dogma, we find that variability may be detrimental to the population growth, suggesting that evolution would tend to suppress it.
Computations in Science

May 16, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - CLOSS LECTURE - Prof. Lauren Webb, Department of Chemistry, University of Texas-Austin

Electrostatic and Electrodynamic Fields in Lipid Bilayer Membranes

Lipid bilayer membranes are complex, dynamic, and functional structures composed of a wide diversity of lipids, proteins, small molecules, and water organized in heterogeneous domains through noncovalent interactions. The structure and motion of these molecules generate large electric fields within the interior of the membrane that are critical to membrane structure and function. Here, we describe how vibrational spectroscopy of unnatural nitrile chromophores places throughout the membrane structure is used to measure electrostatic fields in peptides intercalated in free-standing lipid bilayer membranes of increasing chemical complexity. In combination with electrodynamics simulations, these experiments highlight how common small molecules such as cholesterol dramatically affect membrane structure and dynamics through large changes to membrane electric fields.For further information please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu. You may also contact the Host,Sara Massey at chamberlainsc@uchicago.edu.
The Tuesday JFI Seminar

May 15, 2018
GCIS W301 | Tuesday, 4:00 pm

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Robert G. Roeder, PhD, Rockefeller University

Mechanisms underlying the cooperative functions of transcriptional coactivators


Biophysical Dynamics

May 15, 2018
GCIS W301 | Tuesday, 1:30 pm

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Lee Lecture: Professor Peidong Yang, University of California Berkeley

CO2 + H2O + Sunlight = Chemical Fuels + O2

Solar-to-chemical (STC) production using a fully integrated system is an attractive goal, but to-date there has yet to be a system that can demonstrate the required efficiency, durability, or be manufactured at a reasonable cost. One can learn a great deal from the natural photosynthesis where the conversion of carbon dioxide and water to carbohydrates is routinely carried out at a highly coordinated system level. There are several key features worth mentioning in these systems: spatial and directional arrangement of the light-harvesting components, charge separation and transport, as well as the desired chemical conversion at catalytic sites in compartmentalized spaces. In order to design an efficient artificial photosynthetic materials system, at the level of the individual components: better catalysts need to be developed, new light-absorbing semiconductor materials will need to be discovered, architectures will need to be designed for effective capture and conversion of sunlight, and more importantly, processes need to be developed for the efficient coupling and integration of the components into a complete artificial photosynthetic system. In this talk I will begin by discussing the challenges associated with fixing CO2 through traditional chemical catalytic means, contrasted with the advantages and strategies that biology employs through enzymatic catalysts to produce more complex molecules at higher selectivity and efficiency. I then discuss a number of different photosynthetic biohybrid systems (PBS) architectures from the last few years, and the numerous strategies to interface biotic and abiotic components. Each demonstrates the advantages of PBSs in converting sunlight, H2O and CO2 into food, fuels, pharmaceuticals, and materials. Finally, I will outline the future of this field, opportunities for improvement, and its role in sustainable living here on Earth, and beyond.
Persons with a disability may call (773) 795-5843 in advance for assistance
Chemistry

May 15, 2018
Kent 120 | Tuesday, 12:00 pm

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Lee Lecture: Professor Peidong Yang, University of California Berkeley

Semiconductor Nanowire Building Blocks: From Flux Line Pinning to Artificial Photosynthesis

Semiconductor nanowires, by definition, typically have nanoscale cross-sectional dimensions, with lengths spanning from hundreds of nanometers to millimeters. These subwavelength structures represent a new class of semiconductor materials for investigating light generation, propagation, detection, amplification, and modulation. After more than two decade of research, nanowires can now be synthesized and assembled with specific compositions, heterojunctions, and architectures. This has led to a host of nanowire photonic and electronic devices, including photodetectors, chemical and gas sensors, waveguides, LEDs, microcavity lasers, and nonlinear optical converters. Nanowires also represent an important class of nanostructure building blocks for photovoltaics as well as direct solar-to-fuel conversion because of their high surface area, tunable bandgap, and efficient charge transport and collection. In this talk, I will present a brief history of nanowire research for the past two decades and highlights several recent examples in our lab using semiconductor nanowires and their heterostructures for photonic and energy applications.
Chemistry

May 14, 2018
Kent 120 | Monday, 4:00 pm

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Bertrand Halperin, Harvard University

What's going on at v=5/2?

Recentexperiments have cast doubt on our understanding of the even-denominatorfractional quantized Hall state with quantum number ν=5/2, which was first observed in1987, in GaAs. Based on numerical calculations, it has long been believed thatthe ground state should be topologically equivalent to either the “Pfaffian”wave function, proposed by Moore and Read, or its particle-hole conjugate, the“Anti-Pfaffian”. Though the two states have many common features, and they haveexactly the same energy in a model that ignores perturbations that break theparticle-hole symmetry of a spin-polarized half-filled Landau level, they aretopologically distinct. In particular,their chiral central charge K, whichdetermines the quantized thermal conductance of their edge states, should havedifferent values, viz., K=7/2 and K=3/2, respectively. Recent measurements designed to distinguishbetween these two possibilities point, instead, to a value K=5/2. I shall review somerecent attempts to understand this situation, as well as speculations aboutother even-denominator quantized Hall states observed in various materials.
Kadanoff Seminar

May 14, 2018
PRC 201 | Monday, 1:30 pm

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SPECIAL JFI Seminar- CLOSS LECTURE - Prof. David Liu, Department of Chemistry & Chemical Biology

Base Editing: Chemistry on a Target Nucleotide in the Genome of Living Cells

Point mutations represent the majority of known human genetic variants associated with disease but are difficult to correct cleanly and efficiently using standard genome editing methods. In this lecture I will describe the development, application, and evolution of base editing, a novel approach to genome editing that directly converts a target base pair to another base pair in living cells without requiring DNA backbone cleavage or donor DNA templates. Through a combination of protein engineering and protein evolution, we recently developed two classes of base editors (BE4 and ABE) that together enable all four types of transition mutations (C to T, T to C, A to G, and G to A) to be efficiently and cleanly installed at target positions in genomic DNA. The four transition mutations collectively account for most known human pathogenic point mutations. Base editing has been successfully performed in a wide range of organisms including bacteria, fungi, plants, fish, frogs, mammals, and even human embryos. We have recently expanded the scope of base editing by enhancing its efficiency, product purity, targeting scope, and DNA specificity. We also show that base editing can function in vivo in post-mitotic somatic cells that do not support efficient homology-directed repair. Finally, we have used our phage-assisted continuous evolution (PACE) system to rapidly evolve Cas9 and base editor variants (xCas9, xCas9-BE3, and xCas9-ABE) with both broadened PAM compatibility and higher DNA specificity. Base editing can be used to correct pathogenic point mutations, introduce disease-suppressing mutations, and create cell and animal models of human disease. Host: Chang Liu via email at changliu@uchicago.edu. Persons with a disability who may need assistace please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu
JFI Special Seminar

May 11, 2018
GCIS W301 | Friday, 4:00 pm

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Shouheng Sun, Brown University

Synthetic Tuning of Nanoparticles to Achieve High Efficiency in Electrocatalysis

Developing highly efficient catalysts is crucial for building practical electrochemical devices for energy conversions and for fuel generation. Here we present a new strategy to control Pt-alloy nanoparticle (NP) catalytic efficiency in acid for highly efficient electrochemical reduction or oxidation reactions.

Using FePt as a model system, we have demonstrated that solid solution structured A1-FePt NPs can be converted to chemically ordered tetragonal L10-FePt NPs. These L10-FePt NPs are not only magnetically hard but also chemically robust against Fe leaching in acid. The fully ordered core/shell L10-FePt/Pt NPs show much enhanced catalysis for not only oxygen reduction reaction (ORR) in 0.1 M HClO4, but also hydrogen evolution reaction (HER) in 0.5 M H2SO4. The concept has been successfully extended to other alloy NP systems. For example, the core/shell L10-CoPt/Pt NPs show even higher activity than the L10-FePt/Pt for ORR, surpassing DOE 2020 targets in both activity and durability. Interestingly, by doping a small percentage of Au into the L10-MPt/Pt, the L10-MPt/PtAu NPs become highly efficient in catalyzing electrochemical oxidation of formic acid, methanol or ethanol without noticeable CO poisoning on the Pt surface. Our studies demonstrate a reliable way of tuning NP core/shell structure to enhance shell catalysis for important energy conversion reactions.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

May 11, 2018
Kent 120 | Friday, 1:15 pm

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Daniel McKinsey, The University of California, Berkeley

Probing Sub-GeV Dark Matter with Superfluid Helium

I will describe a dark matter detection technology that will be sensitive to nuclear recoils of sub-GeV dark matter, using superfluid helium as a target. I will briefly review the state of the field of direct dark matter detection, describe motivations to search for sub-GeV dark matter particles and then explain the merits of superfluid helium as a detector material. These include good kinematic matching to low mass dark matter, excellent intrinsic radiopurity, and its unique ability to be cooled down as a liquid to milli-Kelvin temperatures. We propose to read out the recoil signals by calorimetry based on transition edge sensor readout. Calorimeters submerged in the liquid will measure prompt scintillation photons with near-100% efficiency, while the long-lived rotons and phonon excitations will be detected by quantum evaporation of helium atoms from the liquid surface, into vacuum, and then onto a calorimeter array. The binding energy from helium absorption to the calorimeter surface allows for the amplification of these quantum evaporation signals, allowing sub-eV recoil energy thresholds. Taking into account the relevant backgrounds and detector discrimination power based on the light:heat ratio, sensitivity projections show that a small detector (~kg scale) can already explore new parameter space.
Physics Colloquium

May 10, 2018
KPTC 106 | Thursday, 4:00 pm

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Daniel Mindiola, University of Pennsylvania

Titanium-Carbon Multiple Bonds and Their Roles in the Catalytic Dehydrogenation of Volatile Alkanes and Methane Olefination


Chemistry

May 10, 2018
Kent 102 | Thursday, 4:00 pm

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Entrapment into orderly growth

¿Coming soon? Come at noon! to eat.
MRSEC Baglunch

May 10, 2018
GCIS E123 | Thursday, 12:00 pm

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Suchitra Sebastian, The University of Cambridge

The Emergent Fundamental – Exotic Collective Phenomena in Correlated Materials

n the quest to understand our universe, complex materials comprising billions of interacting electrons provide new insight akin to probing alternative universes. Where elementary excitations are considered the fundamental fabric of our universe, we find exotic phenomena defined by novel collective excitations to emerge in correlated electron systems, offering a glimpse of the new fundamental. I will discuss experimental tools by which we can discover and understand such unconventional phases of matter, in particular by fine-tuning materials universes under extreme conditions such as applied pressure and high applied magnetic fields. I will explore examples from my work on materials families such as copper oxide high temperature superconductors, and dual metal-insulating rare earth systems, which display strikingly unusual emergent physical properties requiring new paradigms of understanding.
Physics Colloquium

May 9, 2018
KPTC 106 | Wednesday, 4:00 pm

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Ralf Riedinger, University of Vienna

Optical Quantum Control of Mechanical Oscillators

Mechanical memory elements, directly coupled to photons at designed telecom wavelengths, possess many advantageous features as nodes for large area quantum networks. While impressive experiments like ground state cooling and phonon lasing have recently been demonstrated, genuine non-Gaussian optical quantum control thus far remains elusive. In this talk, I will discuss how the non-linearity of single photon detection can be employed to create non-trivial quantum states. I present recent experimental results on the optical generation of single phonon Fock states and remote entanglement of two massive mechanical oscillators, using silicon optomechanical crystals. Our work introduces mechanical memory elements based in silicon photonics as a new resource for future quantum information systems.
JFI Special Seminar

May 9, 2018
GCIS E223 | Wednesday, 1:30 pm

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Leigh Orf, University of Wisconsin

Simulating and visualizing the most devastating thunderstorms

Tornadoes are among nature's most destructive forces. The most violent, long-lived tornadoes form within supercell thunderstorms. In this seminar, results from simulations of tornado-producing supercell thunderstorms at ultra-high resolution will be presented, as well as the technical challenges involved in conducting, analyzing and visualizing such simulations.

In a control simulation, tornado formation occurs in concert with processes not clearly seen in previous supercell simulations. Visualizations of model fields presented at very high temporal resolution (up to 1/6 of a second, the model time step) will be presented. These animations reveal a fascinating combination of processes that lead to the formation of a long lived very violent tornado that persists for well over an hour. In order to facilitate the saving and visualizing of large amounts of model data, a file system was developed that utilizes the HDF file format and ZFP lossy file compressio! n, and th is file system and associated middleware, dubbed LOFS, will be also described.
Computations in Science

May 9, 2018
KPTC 206 | Wednesday, 12:15 pm

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Johannes Jotterbach

Unsupervised Machine Learning on the Rigetti Quantum Computer

The fourth tutorial in the Quantum Computing Tutorial Series
Molecular Engineering

May 9, 2018
ERC 161 | Wednesday, 12:00 pm

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Nicholas Melosh, PhD, Materials Science & Engineering, Stanford

Engineering Inorganic-Biological Interfaces: Nanofluidic Cell Access & Massively Parallel Brain-Machine Interfaces


Biophysical Dynamics

May 8, 2018
GCIS W301 | Tuesday, 12:30 pm

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Delia Milliron, University of Texas at Austin

Surface Depletion in Conducting Metal Oxide Nanocrystals

Synthetic control over colloidal metal oxide nanocrystals has advanced so that aliovalent dopants can be introduced, producing degenerately doped semiconductors, such as indium tin oxide (ITO), with metal-like optical properties. The localized surface plasmon resonance (LSPR) absorption of these nanocrystals lies in the infrared range, while their large bandgap makes them transparent to visible light. Since the LSPR absorption can be modulated electrochemically, applications including smart windows that dynamically control solar heat gain can be envisioned. I will discuss how the depletion of electron density near the surface of the conducting nanocrystals controls the extent of modulation achievable; material parameters such as dopant concentration and nanocrystal size can be tuned to achieve desirable dynamic response. Depletion also creates a barrier to electron transport between nanocrystals in a thin film. Orders of magnitude enhancement in conductivity of transparent conductive thin films is demonstrated by tuning dopant spatial distribution and nanocrystal surface chemistry to minimize depletion.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

May 7, 2018
Kent 120 | Monday, 4:00 pm

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Katherine A. Schreiber, Purdue University

Hydrostatic Pressure Studies of the Second Landau Level of a Two-Dimensional Electron System

The fractional quantum Hallstates are important phases of the two dimensional electron system in galliumarsenide, known for displaying perfect quantization of the Hall resistance. Ofparticular interest are the ν = 5/2 and ν = 7/2 quantum Hall states, predictedto host non-Abelian statistics. However, these states are not yet wellunderstood because they are so fragile, so new and refined experimentaltechniques are required to learn more about them. Hydrostatic pressure appliedto a semiconductor system changes the band structure, so we may use it tochange the energy scales influencing the quantum Hall states. Motivatedtherefore to probe the ν = 5/2 and ν = 7/2 quantum Hall states, we appliedpressure up to 30 kbar to our GaAs sample. Excitingly, we observed apressure-induced phase transition at ν = 5/2 and ν = 7/2 from fractionalquantum Hall state to nematic phase, a spontaneously broken rotational symmetryphase displaying significant resistance anisotropy. This was the first time atransition from a fractional quantum Hall state to nematic phase was observedat ν = 5/2 and ν = 7/2 in a two-dimensional electron system in the absence ofan external symmetry breaking field. The transition appears to be a quantumphase transition that occurs at the same critical magnetic field for both the ν= 5/2 and ν = 7/2 states, suggesting that electron-electron interactions play adominant role as a mechanism for this transition.
Kadanoff Seminar

May 7, 2018
PRC 201 | Monday, 1:30 pm

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Chi Wu, The Chinese University of Hong Kong

Anti-biofouling: How a polymer brush repels proteins and our novel integrated design

Grafting a layer of chains on a surface to form a polymer brush has been considered as an effective approach to make it anti-biofouling (less protein adsorption). The anti-biofouling property has been qualitatively attributed to the hydration of such a polymer brush with a layer of immobile water molecules and the steric effect; namely, the adsorption decreases monotonically as the polymer grafting density (σ) increases. However, there is no quantitative and satisfactory explanation why the adsorption starts to increase when σ is sufficiently high and why polyethylene glycol (PEG) still remains as one of the best to repel proteins. We have looked the captioned question from another angle: the entropic elasticity instead of the protein-surface interaction, i.e., the enthalpy change.

Considering that each grafted chain is confined inside a cylindrical “pore/tube” made of its neighboring chains, as shown in the right figure, we found its optimal length by minimizing its free energy (A) that contains the exclude volume interaction and the chain elasticity (both of them have an entropic nature) [1, 2]; estimated how A depends on σ and the chain length (L); and calculated its thermal energy-agitated chain conformation fluctuation that slows down the adsorption kinetically. After comparing A with the thermal energy, we are able to predict how both L and  affect the protein repelling and explain why PEG performs better than others. Our predictions are surprisingly and quantitatively comparable with those literature results [3, 4].

We will also illustrate how to develop some novel anti-biofouling coatings for shipyard/marine applications by using an integrated design that combines different existing strategies; namely, the self-polishing, the self-structure and the self-generated soft and dynamic surface [5, 6].

Molecular Engineering

May 7, 2018
ERC 301B | Monday, 11:00 am

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Ming-Yu Ngai, Stony Brook University

Development of Novel Chemical Tools for Accessing Unexplored Chemical Spaces

Synthetic methodologies that allow access to new chemical spaces are of paramount importance to modern drug discovery. Fluorine-containing compounds represent a unique c2hemical space that has caused a fundamental paradigm change in life science research over the past 50 years. There is a significant gap, however, between the needs of the chemical industry and the current methodological efficiency of incorporating fluorinated moieties into organic compounds. To bridge this gap, one of our research programs aims to develop novel reagents and general transformations for the synthesis of fluorinated compounds. In this lecture, I will present our recent efforts to establish mild and operationally simple reactions for the installation of understudied trifluoromethoxy (OCF3) group and polyfluoroalkoxy (ORf) groups into organic molecules. These groups are appealing as they can often enhance molecular efficacy by increasing metabolic stability, promoting binding affinity with targets, and improving cellular membrane permeability of the parent compounds. Nevertheless, due to the lack of general synthetic methods for the introduction of these fluorinated groups, their potential has not been fully exploited in pharmaceutical, agrochemical, and materials applications. Thus, we hope that our research program will allow access to and study of unexplored chemical spaces to aid the discovery and development of new drugs, biocompatible materials, bio-probes, and imaging agents.
Chemistry

May 4, 2018
Kent 120 | Friday, 1:15 pm

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Lena F. Kourkoutis, Cornell University

New frontiers in cryo-electron microscopy: From Probing Low Temperature Electronic Phases to Processes at Liquid/Solid Interfaces

Scanning transmission electron microscopy techniques have enables direct visualization and quantification of the structure, chemistry and bonding of interfaces, reconstructions, and defects. So far, most efforts in the physical sciences have focused on room temperature measurements where atomic resolution spectroscopic mapping has been demonstrated. For many materials, including those that exhibit electronic and structural phase transitions below room temperature and systems that involve liquid/solid interfaces, measurements at low temperature are required. Operating close to liquid nitrogen temperature gives access to a range of emergent electronic states in solid materials and allows us to study processes at liquid/solid interfaces immobilized by rapid freezing.

In this talk, I will discuss our approach to study two processes at the anode-electrolyte interface in lithium metal batteries (LMBs), uneven deposition of lithium metal leading to dendrite growth and the breakdown of electrolyte to form a “solid-electrolyte interphase” (SEI) layer, processes which result in capacity fade and safety hazards. By combining cryo-electron microscopy with cryo-FIB lift out, we provide nanoscale compositional information about intact SEI layers in cycled LMBs and track local bonding states at interfaces, leading to new insights into SEI and dendrite formation (Figure right).

We further demonstrate sub-Å resolution imaging of crystalline solids at cryogenic temperature, and map the nature and evolution of incommensurate charge order in a manganites. We measure picometer-scale displacive modulations of the cations, distinct from existing manganite charge-order models, and reveal temperature-dependent phase inhomogeneities in the modulations, such as shear deformations and topological defects. At temperatures well below T c phase coherence emerges (Figure left). Using cryo- STEM, the role of the lattice in a variety of low temperature electronic phases can now be quantified with high resolution and precision.
Physics Colloquium

May 3, 2018
KPTC 106 | Thursday, 4:00 pm

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IME Distinguished Colloquium Series: Ronald Germain

Combining Imaging and Cell-based Systems Analysis to Develop a Deep Understanding of Immunity

Recent advances in genomic, flow cytometric, and imaging technologies have increasingly emphasized highly multiplexed examination of biological systems at the single cell level. Our dynamic and static imaging methods, including newly devised highly multiplex 3D methods, have begun to provide a comprehensive spatiotemporal understanding of immune system operation in situ. A key theme that has emerged from this work is the role of fine grained levels of tissue organization in producing efficient adaptive immune responses from an inherently inefficient, sparse system. Our studies have also revealed that several paradigmatic views of cell behavior are not accurate when examined in vivo, while studies of innate immune myeloid cells have provided new insights into regulation of inflammatory tissue damage. At the system biology level, RNA-seq as well as mass-spectrometric examination of cell state (CyTOF analysis) have led to the putative definition of an increasingly large number of cell subsets, approaching the ‘snowflake’ paradigm of every cell being unique. In this lecture, I will discuss some of the key issues pertaining to the origin of variation in RNA and protein expression among what appear to be members of a single cell subset (e.g., TCR transgenic, naïve, resting CD8+ T cells), how such variation affects cellular responses to stimulation, and how predictable, functional biology emerges in an organism with cells, especially rare members of the adaptive immune system, occupying diverse microstates at any given time. Issues to be discussed include: (i) whether cells respond in an ‘instantaneous’ manner dependent on momentary microstate or integrate signals over time as the state changes to decrease the heterogeneity of response, (ii) whether clustering algorithms applied to RNA-seq data reveal stable differentiated subsets of cells or transient fluctuation in sets of co-regulated genes, and (iii) whether individual cells with multiple receptors whose expression varies in time respond with full integration of multiple signals or if biology emerges from the sum of distinct behaviors of individual cells.

This research was supported by the Intramural Research Program of NIAID, NIH.
Molecular Engineering

May 3, 2018
ERC 161 | Thursday, 11:00 am

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Ray Moellering, University of Chicago

Integrated Chemical Proteomic Platforms to Probe Metabolic Signaling Across Scales of Space, Time and Reactivity

Biological systems are inherently heterogeneous, both at the molecular level (e.g., encoded proteins existing in distinct posttranslational modification states) and the cellular level (e.g., organization of biomolecules to distinct regions of a cell or distinct cells within a tissue). To understand regulatory mechanisms in these systems under normal or diseased states, we must be able to probe biomolecular function in native environments across scales of space and time. Existing proteomic platforms provide quantitative snapshots of the proteins present in a biological sample, yet these methods typically require homogenization of samples, signal-averaging over thousands-to-millions of cells, and provide no information on protein function. Therefore, innovation in the development chemical probes and technology platforms is needed to study protein activity within complex native environments. In the first part of this talk I will describe the development of new chemical probes and complimentary proteomic technologies to enable quantitative measurements in the proteome in native biological contexts – ranging from subcellular complexes, single cells, primary tissues to live animals. In the second half of this talk I will describe the integration of these platforms to discover new roles for reactive endogenous metabolites as intracellular signals in normal and diseased biological states, as well as the potential to regulate these signals for therapeutic benefit. Both halves of the talk will emphasize the role of these integrated chemical proteomic platforms as a discovery engine to identify novel targets for diagnostic and therapeutic development in human disease.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

May 2, 2018
Kent 120 | Wednesday, 4:00 pm

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Ned Wingreen, Princeton

Magic numbers in protein phase transitions

Biologists have recently come to appreciate that eukaryotic cells are home to a multiplicity of non-membrane bound compartments, many of which form and dissolve as needed for the cell to function. These dynamical "condensates" enable many central cellular functions – from ribosome assembly, to RNA regulation and storage, to signaling and metabolism. While it is clear that these compartments represent a type of separated phase, what controls their formation, how specific biological components are included or excluded, and how these structures influence physiological and biochemical processes remain largely mysterious. I will discuss recent experiments on phase separated condensates both in vitro and in vivo, and will present theoretical results that highlight a novel “magic number” effect relevant to the formation and control of two-component phase separated condensates.
Computations in Science

May 2, 2018
KPTC 206 | Wednesday, 12:15 pm

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Phillip L. Geissler, PhD, Chemistry, UC Berkeley

Driven to distraction: Nonequilibrium fates in biomolecular self-assembly


Biophysical Dynamics

May 1, 2018
GCIS W301 | Tuesday, 12:00 pm

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Bloch Lecture: Dr. Carl Decicco, Bristol-Myers Squibb

Innovation in Drug Discovery and Promising New Medicines

Developing medicines is a complex process. Recent advances in drug discovery have led to transformational new drugs in cardiovascular disease, hepatitis C, Auto-immunity and the exciting and rapidly advancing field of Immuno-oncology. As we investigate new compounds, we are building off of a growing body of evidence that has accumulated over time, illuminating pathways of disease and providing insight into the optimal drug targets. These breakthroughs are leading to transformational new therapies that are having a profound impact on the lives patients and their families. This lecture will focus on important contributions to medicine from the BMS laboratories.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

April 30, 2018
Kent 120 | Monday, 4:00 pm

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Zlatka Minev, Department of Applied Physics, Yale University

To Catch and Reverse a Quantum Jump Mid-Flight

A quantum system driven by a weak deterministic force while under strong continuous energy measurement exhibits quantum jumps between its energy levels. This celebrated phenomenon is emblematic of the special nature of randomness in quantum physics. The times at which the jumps occur are reputed to be fundamentally unpredictable. However, certain classical phenomena, like tsunamis, while unpredictable in the long term, may possess a degree of predictability in the short term, and in some cases it may be possible to prevent a disaster by detecting an advance warning signal. Can there be, despite the indeterminism of quantum physics, a possibility to know if a quantum jump is about to occur or not? In this paper, we answer this question affirmatively by experimentally demonstrating that the completed jump from the ground to an excited state of a superconducting artificial atom can be tracked, as it follows its predictable "flight," by monitoring the population of an auxiliary level coupled to the ground state. Furthermore, we show that the completed jump is continuous, deterministic, and coherent. Exploiting this coherence, we catch and reverse a quantum jump mid-flight, thus preventing its completion. This real-time intervention is based on a particular lull period in the population of the auxiliary level, which serves as our advance warning signal. Our results, which agree with theoretical predictions essentially without adjustable parameters, support the modern quantum trajectory theory and provide new ground for the exploration of real-time intervention techniques in the control of quantum systems, such as early detection of error syndromes.
JFI Special Seminar

April 30, 2018
GCIS E223 | Monday, 3:00 pm

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Eric Bergshoeff, University of Goettingen

Newton-Cartan Gravity in Action

In the first part of this talk I will give a short review of the frame-independent formulation of Newtonian gravity, called Newton-Cartan Gravity, and explain why there is a renewed interest into non-relativistic gravity in general. In the second part I will discuss, as a particular application, a recent proposal for an Effective Field Theory describing a massive spin-2 mode (the so-called GMP mode) in the Fractional Quantum Hall Effect.
Kadanoff Seminar

April 30, 2018
PRC 201 | Monday, 1:30 pm

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Timothy Newhouse, Yale

Total Synthesis of Neurologically Active Terpenoid Natural Products

This talk will describe the total synthesis of neurologically active terpenoid natural products using novel strategies and methodologies for step-efficient syntheses. Methodological developments in the area of allyl-palladium catalysis will be described in detail that have allowed for alpha,beta-dehydrogenation of a variety of carbonyl compounds. Unique strategies and key retrosynthetic disconnections are guided by computational investigation.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

April 27, 2018
Kent 120 | Friday, 1:15 pm

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Cooperative swirling within cell colonies

We eat our food at noon
We watch swirling at 12:15
MRSEC Baglunch

April 27, 2018
GCIS E123 | Friday, 12:00 pm

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Martin Zwierlein, Massachusetts Institute of Technology

Strongly Interacting Fermi Gases under the Microscope

Strongly interacting fermions govern the physics of e.g. high-temperature superconductors, nuclear matter and neutron stars. The interplay of the Pauli principle with strong interactions can give rise to exotic properties that we do not even understand at a qualitative level. In recent years, ultracold Fermi gases of atoms have emerged as a pristine platform for the creation and study of strongly interacting systems of fermions. Near Feshbach resonances, such gases display superfluidity at 17% of the Fermi temperature. Scaled to the density of electrons in solids, this corresponds to superfluidity far above room temperature. Confined in optical lattices, fermionic atoms realize the Fermi-Hubbard model, believed to capture the essence of cuprate high-temperature superconductors. In recent experiments on two-dimensional Fermi gases under a microscope, we observe metallic, Mott insulating and band insulating states with single-site, single-atom resolution. The microscope allows for the site-resolved detection of charge and spin correlations, and for a direct measurement of the transport properties of the Fermi-Hubbard model.
Physics Colloquium

April 26, 2018
KPTC 106 | Thursday, 4:00 pm

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Martin van Hecke, Leiden Institute of Physics

Sequential Mechanical Metamaterials

Ordered sequences of motions govern the morphological transitions of a wide variety of natural and man-made systems, while the ability to interpret time-ordered signals underlies future smart materials that can be (re)programmed and process information. After a short introduction to mechanical metamaterials, we introduce here two novel classes of mechanical metamaterials, that can (1) exhibit sequential output and (2) are sensitive to sequential input. To obtain metamaterials that translate a global uniform compression into a precise multistep pathway of reconfigurations, we combine strongly nonlinear mechanical elements with a multimodal hierarchical structure, and demonstrate multi-step reconfigurations of digitally manufactured metamaterials. To obtain metamaterials that are sensitive to a sequence of mechanical inputs, we introduce the notion of non-commuting metamaterials. Our work aims to establish generic principles for infusing metamaterials with sequential input and output.
Computations in Science

April 25, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - CLOSS LECTURE - Prof. Garnet Chan, Department of Chemistry, Princeton University

Recent Progress in Quantum Chemistry

I will review some of the recent progress made in my group in quantum chemistry methodology and its applications across a variety of problem areas, including metalloenzyme electronic structure, the precision modeling of materials, and the theory of high temperature superconductivity. If time permits, I will also discuss some recent ideas in the areas of quantum dynamics and quantum algorithms on quantum computers.For further information please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu. You may also contact the Host, Polina Navotnaya at pnavotnaya@uchicago.edu
The Tuesday JFI Seminar

April 24, 2018
GCIS W301 | Tuesday, 4:00 pm

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Harkins Lecture: Xiaowei Zhuang, Howard Hughes Medical Institute, Harvard University

Illuminating Biology at the Nanoscale and Systems Scale by Imaging

Dissecting the inner workings of a cell requires imaging methods with molecular specificity, molecular-scale resolution, and dynamic imaging capability such that molecular interactions inside the cell can be directly visualized. However, the diffraction-limited resolution of light microscopy is substantially larger than molecular length scales in cells, making many sub-cellular structures difficult to resolve. Another major challenge in imaging is the low throughput in the number of molecular species that can be simultaneously imaged, while genomic-scale throughput is desired for investigating systems level questions. In this talk, I will describe two imaging methods that overcome these challenges and their biological applications. I will first describe STORM, a super-resolution imaging method that overcomes the diffraction limit. This approach allows multicolor and three-dimensional imaging of living cells with nanometer-scale resolution. I will present both technological advances and biological applications of STORM, with focus on recent biological discoveries enabled by STORM. I will then describe MERFISH, a single-cell transcriptome and chromosome imaging method that allows numerous RNA species and genomic loci to be imaged in individual cells. This approach enables mapping of the spatial organization of the transcriptome and genome inside cells and distinct cell types in complex tissues.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

April 23, 2018
Kent 120 | Monday, 4:00 pm

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K.C. Nicolaou, Rice University

The Art and Science of Organic Synthesis and its Impact on Biology and Medicine

This lecture will cover advancements in chemical synthesis and their applications to biomedical research. A number of examples of total syntheses featuring cascade reactions and other novel strategies and methods will be presented. The impact of the synthetic strategies and technologies developed in these endeavors on biology and medicine through analogue design, synthesis and biological investigations will also be discussed.
Chemistry

April 20, 2018
Kent 120 | Friday, 1:15 pm

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As I Lie Dying: A nanoparticle spins towards its demise

It's not as sad as it sounds…

Eat 12:00
Saga: 12:15
MRSEC Baglunch

April 20, 2018
GCIS E123 | Friday, 12:00 pm

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Geoff Coates, Cornell University

In Pursuit of the Perfect Plastic

Society depends on polymeric materials more now than at any other time in history. Although synthetic polymers are indispensable in a diverse array of applications, ranging from commodity packaging and structural materials to technologically complex biomedical and electronic devices, their synthesis and disposal pose important environmental challenges. The focus of our research is the development of sustainable routes to polymers that have reduced environmental impact. This lecture will focus on our research to transition from fossil fuels to renewable resources for polymer synthesis, as well as the development of polymeric materials designed to bring positive benefits to the environment.
Molecular Engineering

April 20, 2018
SCL 240A&B | Friday, 11:00 am

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Rama Ranganathan, The University of Chicago


Physics Colloquium

April 19, 2018
KPTC 106 | Thursday, 4:00 pm

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William Dichtel, Northwestern University

Rapid Sequestration of Organic Micropollutants From Water Using Porous Cyclodextrin Polymers

Organic micropollutants, such as pesticides and pharmaceuticals, have raised concerns about negative effects on ecosystems and human health. These compounds are introduced into water resources by human activities, and current wastewater treatment processes do not remove them. Activated carbons are the most widespread adsorbents used to remove organic pollutants from water, but they have several deficiencies, including poor removal of relatively hydrophilic micropollutants, inferior performance in the presence of naturally occurring organic matter, and energy intensive regeneration processes. β-cyclodextrin, an inexpensive, sustainably produced derivative of glucose, encapsulates micropollutants in water. We link β-cyclodextrin into permanently porous polymers that bind micropollutants with adsorption rate constants 15 to 200 times greater than competing adsorbent materials. The polymers bind pollutants with high affinity, yet can be easily regenerated and reused. We also recently modified our original polymer design to target perfluorinated compounds such as PFOA, which are environmentally persistent associated with negative effects at trace concentrations.

Molecular Engineering

April 19, 2018
ERC 201 | Thursday, 11:00 am

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Alfred Crosby, University of Massachusetts Amherst

Materials Mechanics for Impulsive Movement

Nature provides amazing examples of high velocity, high acceleration, impulsive movements that can be repeated numerous times over the course of an organism’s lifetime. Synthetic, or engineered, devices, on the other hand, are often challenged to achieve comparable performance across a wide range of size scales. Common to nature’s examples, including mantis shrimp and trap-jaw ants, is the integration of three essential components for elasticity-assisted movement: an actuator, spring, and latch. Elasticity-assisted motion has been utilized for thousands of years to amplify the power of natural or synthetic actuators; however, the scaling physics of these multi-component systems, especially in light of materials design, have not been widely considered. Here, we discuss our group’s efforts, within a multi-university collaborative team, to lay a foundation for understanding the role that materials properties and structure play in the performance of impulsive systems in nature with an eye toward aiding the development of engineered devices that can overcome current limitations. We first discuss the mechanics of elastic recoil and a set of systematic experiments on a resilin-like synthetic material. The results from this study leads to a common framework for describing the roles of geometry and materials properties for controlling duration, velocity, and acceleration. We then introduce recent advances of using mesoscale polymers, which build upon previously introduced concepts from our group, to develop high rate, large strain, microscale actuators. Collectively, these examples highlight the integrative approach of our group and how we use bio-inspired materials mechanics to inspire new technologies and provide fundamental insight.
Computations in Science

April 18, 2018
KPTC 206 | Wednesday, 12:15 pm

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Sriram Kosuri, UCLA

Synthetic Approaches to Understanding Biology

I will discuss three projects in our lab where we develop new technologies to allow for the construction and functional testing of large libraries of reporters to explore (1) human genetic variation and splicing, (2) structure/function of antibacterial gene target homologs, and (3) human G-protein coupled receptors.
Molecular Engineering

April 18, 2018
ERC 161 | Wednesday, 10:00 am

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Susan Marqusee MD/PhD, UCBerkeley

Watching protein folding on & off the ribosome


Biophysical Dynamics

April 17, 2018
GCIS W301 | Tuesday, 12:00 pm

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Mulliken Lecture: Professor John P. Perdew, Temple University

The SCAN Density Functional: Predictive Power of 17 Exact Constraints

Kohn-Sham density functional theory in principle predicts the exact ground-state energy and electron density of a many-electron system via the solution of self-consistent one-electron Schrödinger equations. Only the exchange-correlation energy as a functional of the density needs to be approximated. For materials discovery, the approximations need to be computationally efficient, predictive, and usefully accurate. The SCAN (strongly constrained and appropriately normed) meta-generalized gradient approximation was constructed to satisfy all 17 known exact constraints that a semi-local functional can satisfy (compared to 11 for the PBE GGA). SCAN is further fitted to appropriate norms, non-bonded systems for which a semi-local functional can be accurate for exchange and correlation separately. SCAN recognizes and provides different GGA-like descriptions for covalent single bonds, metallic bonds, and van der Waals (vdW) bonds. Here I will review the functional itself, along with its long-range vdW extension SCAN+rVV10. I will also review applications to properties of diversely-bonded systems, including ferroelectricity, density and structure of liquid water, crystal structure stability, surface properties of transition metals, and critical pressures for structural phase transitions of semiconductors. The accuracy of SCAN is often comparable to or better than that of a hybrid functional, at lower computational cost and without any fitting to bonded systems.
Chemistry

April 16, 2018
Kent 120 | Monday, 4:00 pm

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Jian Kang, National High Magnetic Field

Interplay between nematicity and superconductivity in tron-based superconductors

Theiron-based high-Tc superconductors exhibit several remarkable features,including the multi-orbital character and the ubiquity of the nematic phase. One consequence of the multi-orbital Fermi surface isthat the spin-fluctuation mediated pairing interactions are sensitive to theorbital spectral weight at the Fermi surface, leading to several differentpossible gap structures, such as nodeless s±, nodal s±, and d-wave. Focused on the orbital order induced in the nematic phase,I will discuss how the nematic order can manipulate the properties of SC. Ourcalculation shows that not only Tc is enhanced, but moreimportantly, the gap structure becomes a mixture of nearly degenerate s andd-wave states by increasing the external strain. This mixture of s and d wavepairing channels has been recently found in the superconducting phase of thebulk FeSe, when SC occurs deeply insider the nematic phase.
Kadanoff Seminar

April 16, 2018
PRC 201 | Monday, 1:30 pm

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Poul Nissen, PhD, Aarhus University, Denmark

Structure and dynamics of P-type ATPase

Active transport plays a major role in cells. In brain, Na,K-ATPase activity alone accounts for an estimated 40-70% of ATP hydrolysis. Also Ca2+-ATPases of the same P-type ATPase family contribute critically to ion homeostasis in all cell types. These activities are fundamental to life, and malfunction is linked to a range of disorders such as neurological and cardiovascular diseases. Using primarily membrane protein crystallography combined with biochemical and electrophysiological studies, single-molecule FRET, molecular dynamics simulations, modelling, & in vivo models, we have contributed to our growing insight into the mechanistic concepts and functional cycle of the mammalian Na,K-ATPase and Ca2+-ATPase ion pumps. Recently we have also initiated cryoEM studies supported by a large Danish-Swedish cryoEM network, and defined rationales for new X-ray and neutron scattering studies based on the emerging facilities at the MAX IV synchrotron and European Spallation Source in Lund and the European XFEL and Petra3 X-ray sources in Hamburg. Hosted by Benoit Roux and Eduardo Perozo
Biophysical Dynamics

April 16, 2018
BSLC 205 | Monday, 12:00 pm

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Wesley A. Chalifoux, University of Nevada

Alkyne Annulations: A Toolkit for Accessing Chemical Diversity from Terpenoids to Conjugated Materials

Readily available alkyne-containing compounds are attractive as high-energy starting materials that allow an efficient, step- and atom-economical synthesis of a host of useful chemical products. Alkynes and polyynes can be used as linchpins in multicomponent and tandem reactions to provide rapid access to biologically pertinent terpenoid scaffolds. The alkyne functional group also allows for the facile synthesis of novel nanographenes and contorted – even chiral – polycyclic aromatics. Alkynes even allow for a mild, non-oxidative (non-Scholl) bottom-up synthesis of atomically precise graphene nanoribbons (GNRs). Synthetic achievements in both of these areas (terpenoid scaffolds and carbon-rich materials) will be presented in this seminar.
Chemistry

April 13, 2018
Kent 120 | Friday, 1:15 pm

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Transient structured fluctuations in a two-dimensional liquid with shouldered pair interaction

Eat and Kibbitz: 12:00
Hear: 12:15
MRSEC Baglunch

April 13, 2018
GCIS E123 | Friday, 12:00 pm

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Heather Knutson, California Institute of Technology

Seeking Clues to Explain the Diverse Architectures of Exoplanetary Systems

Over the past two decades ongoing surveys have detected thousands of new planetary systems around nearby stars. These systems include apparently single gas giant planets on short period orbits, closely packed systems of up to 5-6 “mini-Neptunes”, and solar-system-like architectures with either one small planet or no planets interior to 0.5 AU. Despite our success in cataloguing the diverse properties of these systems, we are still struggling to develop narratives that can explain their divergent evolutionary paths. In my talk I will describe two promising new avenues of investigation, including constraints on the compositions of short-period planets and statistical studies of the frequency of outer gas giant and stellar companions in these systems. Taken together, these observations provide important clues that can be used to determine whether or not the observed population of short period exoplanets formed in situ or migrated in from farther out in the disk.
Physics Colloquium

April 12, 2018
KPTC 106 | Thursday, 4:00 pm

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Professor Hisashi Yamamoto, Professor and Director of Molecular Catalyst Research Center, Chubu University; Arthur Holly Compton Distinguished Professor Emeritus, The University of Chicago; Professor of Emeritus, Nagoya University

From Lewis Acid Catalyst to Catalytic Peptide Synthesis

Catalytic peptide synthesis is the long-standing problems for chemical synthesis. One of the most difficult problems for previous synthesis is that the required activated carboxylic acid which caused 1) the racemization of the product and 2) the equimolar usage of the activated ester unit results significant amounts of side products. These issues result difficult to purify the product from by-products.
Generally, Lewis acid catalyst interacts the basic site of molecule and activates another functional group nearby the activated site. Because of the activation by Lewis acid catalyst, even simple methyl ester is able to be used for the reaction. This activation process will avoid any racemization path since the coordination of Lewis acid to the methyl ester may not be attacked by the amide oxygen intramoleculaly. For the basic site (anchor) of the molecules, we are able to use hydroxyl group or equivalents, such as hydroxyl amine, oxime, or BOC protecting amino groups. Lewis acid catalyst can be used various metal alkoxides such as Ta or Nb alkoxides with 1-10 mol% loading. Generally, the amidation proceeds without using any solvent from room temperature up to 80oC in quantitative yields.
With this simple procedure in hand, we are able to introduce the new amino acid unit to the polypeptide chain in two steps with high yields. The proposed process has huge potential for future drug industry.
Chemistry

April 12, 2018
GCIS W301 | Thursday, 1:00 pm

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Thomas Cech, PhD, Chemistry and Biochemistry, University of Colorado Boulder, HHMI

Shedding some Light on the Dark Matter of the Genomic Universe

In all of life on Earth, information flows from DNA to RNA to Protein. Thus, RNA has a role as a message, transmitting the information encoded in our chromosomal DNA. LncRNAs (long noncoding RNAs) have long been the “dark matter” of the genome, but they also have active roles in biology, even acting as enzymes (ribozymes). Another lncRNA is found in the telomerase RNP, which extends the DNA at chromosome ends and thereby contributes to genome stability. Finally, the binding of lncRNAs to PRC2 helps regulate epigenetic silencing of gene expression.
Biophysical Dynamics

April 11, 2018
BSLC 115 | Wednesday, 2:00 pm

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Ward Lopes, NVIDIA

A Careers-in-science discussion with a UChicago Alumnus

Ward Lopes is a Sr. Research Scientist who works on display research. His main research interests are applications of dynamic, computer generated holography and holographic optical elements in virtual-, augmented-, and mixed-reality. Prior 2015, Ward focused on self-assembly processes in soft condensed matter and applications of holography in optical micromanipulation and microscopy. Ward has publications on a variety of topics from nano-scale self-assembly and nanotechnology, bio-physics, holographic optical trapping, laser physics, to measurement techniques in the geosciences. Prior to joining NVIDIA, Ward was a physics professor at Williams College and at Mount Holyoke college, and was the Director of Product Research at Arryx, Inc. While at Arryx, he was awarded the R&D 100 Award by R&D Magazine for the 100 “most technologically significant products introduced into the marketplace” for the BioRyx200 system (a holographic optical trapping system).
Careers In Science

April 11, 2018
KPTC206 | Wednesday, 2:00 pm

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Michael Shelley, NYU Courant, Flatiron Institute

Active Mechanics in the Cell

Many fundamental phenomena in eukaryotic cells -- nuclear migration, spindle positioning, chromosome segregation -- involve the interaction of often transitory structures with boundaries and fluids. I will discuss the interaction of theory and simulation with experimental measurements of active processes within the cell. This includes understanding the force transduction mechanisms underlying nuclear migration, spindle positioning and oscillations, as well as how active displacement domains of chromatin might be forming in the interphase nucleus.
Computations in Science

April 11, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - Prof. Sriram Ramaswamy, Indian Institute of Science

Active Soft Matter and Other Stories

Active Matter was formulated to incorporate living materials into the capacious fold of condensed-matter and statistical physics. My talk will discuss the successes of this approach on scales from micrometres to kilometres in living and artificial systems; relate active-matter problems to more familiar nonequilibrium phenomena such as sedimentation; and highlight our recent work on (in)stability, defects, flocking and collective trapping, especially in artificial realisations of collective motility.
For further information please contact Brenda Thomas at 773-702-7156 or via email at bthomas@uchicago.edu. You may also contact the Host, Suri Vaikuntanathun at 773-702-7256 or by email at svaikunt@uchicago.edu.
The Tuesday JFI Seminar

April 10, 2018
GCIS W301 | Tuesday, 4:00 pm

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Aron Pinczuk, Columbia University

Experimental studies of magnetoroton modes of fractional Quantum hall fluids

Quantum Hall phases are archetypes of the remarkable many-electron physics that emerges in electron fluids under conditions of greatly reduced dimensionality.
Magnetoroton modes are characteristic low-energy excitations that manifest underlying fundamental interactions in fractional quantum Hall fluids.
Inelastic light scattering methods at very low temperatures are experimental venues to study low-lying excitations of quantum Hall fluids. Of particular interest are the
excitation modes that demonstrate novel quantum liquid behavior and that offer insights on unexpected collective responses. Besides magnetorotons, low-lying spin wave modes that probe rotational invariance of spin are of interest here.
This presentation considers inelastic light scattering studies of low-lying excitations that probe intriguing physics of quantum Hall fluids. Early results in the partially populated lowest Landau level, at filling factors n=1/2 and n=1/3, will be reviewed. More recent results considered are observations of excitations of the electron fluids that reside in the partially populated second Landau level (filling factors n=5/2 and n=7/3).
Kadanoff Seminar

April 9, 2018
PRC 201 | Monday, 1:30 pm

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Lucy Colwell, Department of Chemistry, University of Cambridge

Using Evolutionary Sequence Variation to Build Predictive Models of Protein Structure and Function

The evolutionary trajectory of a protein through sequence space is constrained by its function. Collections of sequence homologs record the outcomes of millions of evolutionary experiments in which the protein evolves according to these constraints. The explosive growth in the number of available protein sequences raises the possibility of using the natural variation present in homologous protein sequences to infer these constraints and thus identify residues that control different protein phenotypes. Because in many cases phenotypic changes are controlled by more than one amino acid, the mutations that separate one phenotype from another may not be independent, requiring us to understand the correlation structure of the data. We show that models constrained by the statistics of the multiple sequence alignment are capable of predicting key aspects of protein function. These include (i) the inference of residue pair interactions that are accurate enough to predict all atom 3D structural models; and predictions of (ii) binding interactions between different proteins and (iii) binding between protein receptors and their target ligands.

The challenge is to distinguish true interactions from the noisy and under-sampled set of observed correlations in a large multiple sequence alignment. Current methods ignore the phylogenetic relationships between sequences, potentially corrupting the identification of covarying positions. Here, we use random matrix theory to demonstrate the existence of a power law tail that distinguishes the spectrum of covariance caused by phylogeny from that caused by phenotypic interactions. The power law is essentially independent of the phylogenetic tree topology, depending on just two parameters - the sequence length, and the average branch length of the tree. We demonstrate that these power law tails are ubiquitous in the large protein sequence alignments used to predict contacts in 3D structure, as predicted by our theory, and confirm that truncating the corresponding eigenvectors improves contact prediction. Finally, I will discuss current efforts to further enhance these methods using recent advances in deep learning. Persons with disability who may need assistance please contact Brenda Thomas at 773-702-7156 or by at bthomas@uchicago.edu or Host: Stephanie Palmer, 773-702-0771 or via email at sepalmer@uchicago.edu
JFI Special Seminar

April 9, 2018
KPTC 206 | Monday, 12:00 pm

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Sylvia T. Ceyer, Massachusetts Institute of Technology

Delving Below and Beyond the Surface

Catalytic surface reactions depend not only on adsorbed species but also on absorbed species. Experiments that document the distinctive reactivity of a H atom embedded in the bulk of a Ni metal catalyst are described. In particular, a H atom emerging from the bulk onto the surface is transiently more energetic by about 24 kcal/mol compared to a H atom adsorbed on the surface. Consequently, it is the reactive species in hydrogenation of adsorbed ethylene and acetylene, respectively, while a H atom adsorbed on the Ni surface is not reactive. These results demonstrate that bulk H is not solely a source of surface bound H in catalytic hydrogenation as proposed 60 years ago, but rather, a reactant with a distinctive chemistry of its own.

In cases where the surface is a reactant rather than a catalyst, a scattering approach has shown two likely origins for the factor of 103 to 104 high etching rate of Si by XeF2 than by F2: significant vibrational excitation of the Si lattice upon initial collision of the massive XeF2, prior to abstraction of the first F atom by Si, and second, the gas phase dissociation of the XeF abstraction product that produces a small fraction of F atoms that are aimed back at the Si surface. This study is a possible example of collisional energy transfer to a surface playing a critical role in the probability of a molecule-surface reaction and is the first documentation of dissociation of a product of a surface reaction in the gas phase.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

April 9, 2018
Kent 120 | Monday, 9:00 am

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Kharasch Lecture: Professor Stephen Buchwald, MIT

Palladium-Based Methodology in Imaging and Bioconjugation

We have started to apply methodology related to Pd-catalyzed C-N coupling to the preparation of isotopically labelled compounds for the purposes of imaging (cf. J. Am. Chem. Soc. 2017, 139, 7152). Additionally, we are working in a variety of areas dealing with the functionalization of biomolecules including peptides, proteins and antibodies (Nature, 2015, 526, 687, Org. Lett. 2017, 19, 4263).

This lecture will describe: 1) Our work on the preparation of 11C-labelled small molecules and peptides. 2) The development of technology for the functionalization of peptides and proteins. 3) A new method for the synthesis of stapled peptides. 4) Applications to the preparation of antibody drug conjugates.
Chemistry

April 6, 2018
Kent 120 | Friday, 1:15 pm

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How sound makes turtles and trees in mid-air

Come with food at noon
Get ready to fly at 12:15
MRSEC Baglunch

April 6, 2018
GCIS E123 | Friday, 12:00 pm

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Michael Brenner, Harvard University

The quest to observe the Turbulent Cascade in real time


Physics Colloquium

April 5, 2018
KPTC 106 | Thursday, 4:00 pm

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Novartis Lecture: Professor Shannon S. Stahl, University of Wisconsin-Madison

Practical Aerobic and Electrochemical Oxidation Reactions

Research in the Stahl lab targets the discovery, development, and mechanistic understanding of new catalysts and catalytic processes, especially related to oxidation reactions. As the most abundant and environmentally benign oxidant available, molecular oxygen is the quintessential oxidant, but controlling its reactivity to achieve selective oxidation of organic molecules presents considerable fundamental and practical challenges. Until recently, aerobic oxidation reactions were virtually never used in process-scale synthesis of fine chemicals, agrochemicals or pharmaceuticals, and they were rarely used in laboratory syntheses. This talk will present a general catalytic strategy for aerobic oxidation reactions, inspired by oxidase enzymes, that is designed to enable widespread use of O2 as an oxidant in chemical synthesis. Fundamental and practical advances in this area will be presented, including highlights of industrial collaborations that have played an important role in these efforts. The "oxidase" approach to aerobic oxidation reactions is conceptually similar to electrochemical redox reactions. Both reaction classes feature the coupling of two independent half-reactions. The aerobic oxidation reactions employ a single catalyst site for both steps, while the electrochemical half-reactions take place at independent electrodes. The relationship between these reactions will be presented, together with recent examples of electrosynthetic oxidation reactions that we have developed.
Chemistry

April 5, 2018
GCIS W301 | Thursday, 3:45 pm

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Novartis Lecture: Professor Tianning Diao, New York University

Strategies for Promoting Nickel-Catalyzed Alkene Functionalization

Ni catalysts have recently emerged as appealing tools in organic synthesis, allowing access to new reactivity in cross-coupling and opening up new avenues in synthesis. Despite the growing use of Ni catalysts, mechanistic understanding of Ni-catalyzed reactions is inadequate, partly due to complex radical intermediates that complicate mechanistic studies. Our group explores the unique reactivity of Ni catalysts from a fundamental perspective, combining mechanistic approaches with method development. I will present three strategies to tame the reactivity of Ni catalysts. Redox-active ligands stabilize Ni(I) and Ni(III) intermediates and allow classic two-electron transformations to take place on a Ni(I)/Ni(III) platform. In addition, we explored Ni-initiated radical formation from alkyl halides to reductively functionalize alkenes. Finally, we show that dinuclear Ni complexes can react cooperatively, facilitating two-electron redox processes by accepting/donating one electron at each metal center.
Chemistry

April 5, 2018
GCIS W301 | Thursday, 3:00 pm

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Novartis Lecture: Professor Mikhail G. Shapiro, California Institute of Technology

Molecular Engineering for Non-Invasive Imaging and Control of Cellular Function

The study of biological function in intact organisms and the development of targeted cellular therapeutics necessitate methods to image and control cellular function in vivo. Technologies such as fluorescent proteins and optogenetics serve this purpose in small, translucent specimens, but are limited by the poor penetration of light into deeper tissues. In contrast, most non-invasive techniques such as ultrasound and magnetic resonance imaging – while based on energy forms that penetrate tissue effectively – are not effectively coupled to cellular function. Our work attempts to bridge this gap by engineering biomolecules with the appropriate physical properties to interact with magnetic fields and sound waves. In this talk, I will describe our recent development of biomolecular reporters and actuators for ultrasound. The reporters are based on a unique class of gas-filled protein nanostructures from buoyant photosynthetic microbes. These proteins produce nonlinear scattering of sound waves, enabling their detection with ultrasound. I will describe our recent progress in understanding the biophysical and acoustic properties of these biomolecules, engineering their mechanics and targeting at the genetic level, developing methods to enhance their detection in vivo and expressing them heterologously as acoustic reporter genes. Our actuators are based on temperature-dependent transcriptional repressors, which provide switch-like control of bacterial gene expression in response to small changes in temperature. We have genetically tuned these repressors to activate at thresholds within the biomedically relevant range of 32ºC to 46ºC, and constructed genetic logic circuits to connect thermal signals to various cellular functions. This allows us to use focused ultrasound to remote-control engineered bacteria in vivo.
Chemistry

April 5, 2018
GCIS W301 | Thursday, 2:00 pm

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Novartis Lecture: Dr. Katsumasa Nakajima, Novartis Institutes for BioMedical Research

Building an Arsenal of Small Molecule DGAT1 Inhibitors to Battle Metabolic Syndrome

Obesity is characterized as excess accumulation of body fat (triglyceride) and contributes to a diagnosis of metabolic syndrome, which is associated with increased risk of cardiovascular disease and diabetes. To battle metabolic syndrome, we initiated a drug discovery program targeting diacylglycerol acyltransferases 1 (DGAT1) which catalyzes the final committed step of triglyceride synthesis. After screening using recombinant human DGAT1 enzyme, diamide and benzimidazole classes of DGAT1 inhibitors were discovered. The diamide compounds were potent DGAT1 inhibitors in vitro but initially lacked suitable molecular properties to inhibit DGAT1 in vivo. Introduction of an aromatic ring as the amide N substituent was found effective to produce an orally bioavailable molecule that potently inhibits DGAT1 in vivo from this series. The benzimidazole series required first optimization of in vitro potency by adding amide and propionic acid groups to the core structure, though these groups kept the molecule from being effectively absorbed in vivo after oral administration. Conversion of the amide to oxadiazole as amide bioisostere and dimethylation at ɑ position in the propionic acid successfully addressed the issue, providing another potent, orally bioavailable DGAT1 inhibitor. This compound demonstrated chronic efficacy by reducing body weight gain in a diet induced obese dog model and was advanced to the clinical investigation along with pradigastat, aminopyridine class of DGAT1 inhibitor that was also developed in our group.
Chemistry

April 5, 2018
GCIS W301 | Thursday, 1:15 pm

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IME Distinguished Colloquium Series: Demetri Psaltis, EPFL


Molecular Engineering

April 5, 2018
ERC 161 | Thursday, 11:00 am

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Benjamin B. Machta, Princeton University

When and why is a simpler model better?

Science is filled with toy models: abstractions of complicated systems that ignore microscopic details even when they are known. For a special class of models in physics, the renormalization group rigorously justifies the use of effective theories containing just a small number of relevant parameters. This philosophy seems to apply more broadly, even when the renormalization group cannot be used. But why? In this talk I will discuss an information theory approach to answering this question, or at least towards quantifying it. I will first review that typical models are sloppy, defined by a hierarchy in parameter importance. I will argue that sloppiness is both necessary and sufficient for a microscopic system to be amenable to description by a simpler effective theory. I will then show how renormalizable models become sloppy as their data is coarse-grained. Finally I will discuss our recent efforts to use the structure of these models to choose simpler effective theories automatically.
Computations in Science

April 4, 2018
KPTC 206 | Wednesday, 12:15 pm

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Kharasch Lecture: Professor Stephen Buchwald, MIT

Asymmetric Hydrofunctionalization Processes for Organic Synthesis

The availability of a general method for the catalytic conversion of olefins into enantiomerically enriched amines has eluded chemists for decades. We have recently developed a simple copper-catalyzed technique to effect such a transformation. This lecture will describe our progress, applications of our methodology as well as our current view of the mechanism of the hydroamination process. In addition, we will describe our progress in developing new catalytic processes for carbon-carbon bond formation that utilize alkyl copper intermediates.
Chemistry

April 4, 2018
GCIS W301 | Wednesday, 12:00 pm

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The JFI First Tuesday Colloquium - Prof. Ignacio Franco, Department of Chemistry, University of Rochester

Stark Control of Electrons

A general goal in our quest to control matter and energy is the design of strategies to control electronic properties and electron dynamics using coherent laser sources. In addition to its interest at a fundamental level, lasers permit manipulation on an ultrafast timescale opening the way to control the ability of matter to chemically react, conduct charge, absorb light, or other properties, in a femto to attosecond timescale.

In this talk, I will summarize our efforts to understand electronic decoherence processes in molecules that are deleterious to interference-based scenarios for the laser control. In addition, I will discuss how, through Stark effects, non-resonant light of intermediate intensity (non-perturbative but non-ionizing) can be used to generate “laser-dressed” molecules and materials with non-equilibrium properties that can be very different from those observed by matter near thermodynamics equilibrium. In particular, I will discuss how Stark effects can be employed to turn transparent nanomaterials into broadband absorbers, and to generate currents in nanoscale junctions.For further information please contact Brenda Thomas at 773-702-7156 or via email at bthomas@uchicago.edu. You may also contact the Host: Timothy Berkelbach 773- 834-9879 or by email at berkelbach@uchicago.edu.
The 1st Tuesday JFI Colloquium

April 3, 2018
GCIS W301 | Tuesday, 4:00 pm

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Thomas T. Perkins, PhD, JILA & University of Colorado Boulder

Probing the equilibrium folding dynamicsof individual bacteriorhodopsin molecules with 1-μs resolution


Biophysical Dynamics

April 3, 2018
GCIS W301 | Tuesday, 12:00 pm

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Kharasch Lecture: Professor Stephen Buchwald, MIT

Palladium-Catalyzed Carbon-Heteroatom Bond-Forming Reactions for Organic Synthesis

Cross-coupling methodology is an indispensable part of the everyday repertoire of synthetic organic chemists. Among the many possibilities, we have focused a great deal of attention on the Pd-catalyzed formation of C-N bonds (Chem. Rev., 2016, 116, 12564); a mechanistic pathway for this transformation is shown below. This methodology has been widely utilized throughout academia and industry.

Crucial to our success in the development of new and more generally applicable methods has been our discovery and use of biaryl monodentate phosphine ligands. These have been licensed for manufacture on large scale to eight companies and are available, in many cases, on very large scale (100's of Kg produced). This methodology has been widely utilized throughout academia and industry.

The history of our work up to the most recent developments will be discussed.
Chemistry

April 2, 2018
Kent 120 | Monday, 4:00 pm

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Jiehang Zhang, University of Maryland

Engineered Quantum Spin Systems: Out-of Equilibrium

Quantum mechanics prescribes exponential scaling of the Hilbert space dimension in many-body systems, which presents both challenges and new opportunities for understanding strongly correlated matter, especially since novel custom-built systems are now available. I will describe such efforts on engineering quantum systems atom by atom, precisely controlling them with laser-driven interactions, and increasing the system size up to a regime where the capabilities of classical computers are challenged.



I will focus on the platform of trapped atomic ions, where a combination of excellent coherence time and high-fidelity measurements has enabled many applications, ranging from simulating condensed matter physics, to quantum computation. We represent spin qubits with electronic levels of ions in a Coulomb crystal, and entangle them through tailored laser pulses. I will present recent experiments using these systems to study dynamical phase with individual resolution for more than 50 spins, as well as non-equilibrium driven matter. I then conclude with future prospects.
JFI Special Seminar

April 2, 2018
GCIS E223 | Monday, 3:00 pm

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Jennifer Cano, Princeton University

Topological Quantum Chemistry

The past decade's apparent success in predicting and experimentally discovering distinct classes of topological insulators (TIs) and semimetals masks a fundamental shortcoming: out of 200,000 stoichiometric compounds extant in material databases, only several hundred of them are topologically nontrivial. Are TIs that esoteric, or does this reflect a fundamental problem with the current piecemeal approach to finding them? To address this, we propose a new and complete electronic band theory that highlights the link between topology and local chemical bonding, and combines this with the conventional band theory of electrons. We classify the possible band structures for all 230 crystal symmetry groups that arise from local atomic orbitals, and show which are topologically nontrivial. We show how our topological band theory sheds new light on known TIs, and demonstrate the power of our method to predict new TIs.
Kadanoff Seminar

April 2, 2018
PRC 201 | Monday, 1:30 pm

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Dr. Jordan Meier, National Cancer Insitute

Illuminating Acetylation's Dark Matter with Chemoproteomics

A paradox of modern acetylation biology is that the while number of sites of acetylation has climbed rapidly, the number of enzymes thought to catalyze this process has stayed relatively constant. Here we describe the utility of chemical proteomic methods to discover and characterize novel mechanisms of acetylation in endogenous cellular contexts. Our studies highlight an expanded landscape of regulatory acetylation in gene expression control, as well as new strategies to investigate the metabolic regulation and small molecule inhibition of acetyltransferases in cells.
Persons with a disability may call (773) 795-5843 in advance for assistance.
Chemistry

March 30, 2018
Kent 120 | Friday, 1:15 pm

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Fred Chong, The University of Chicago

Scaling up Quantum Computers

Quantum computing is at an inflection point, where 50-qubit (quantum bit) machines have been built, 100-qubit machines are just around the corner, and even 1000-qubit machines are perhaps only a few years away. These machines have the potential to fundamentally change our concept of what is computable and demonstrate practical applications in areas such as quantum chemistry, optimization, and quantum simulation.
Yet a significant resource gap remains between practical quantum algorithms and near-term machines. Programming, compilation and control will play a key role in increasing the efficiency of algorithms and machines to close this gap.
I will outline the grand research challenges in closing this gap, including programming language design, software and hardware verification, defining and perforating abstraction boundaries, cross-layer optimization, managing parallelism and communication, mapping and scheduling computations, reducing control complexity, machine-specific optimizations, and many more. I will also describe the resources and infrastructure available for tackling these challenges.
Physics Colloquium

March 29, 2018
KPTC 106 | Thursday, 4:00 pm

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Ken Kamrin, MIT

Modeling flowing granular material as a continuum: Surprising complexity meets surprising simplicity

Granular materials are common in everyday life but are historically difficult to model. This has direct real-world ramifications owing to the prominent role granular media play in multiple industries and in terrain dynamics. One can attempt to track every grain with discrete particle methods, but realistic systems are often too large for this approach and a continuum model is desired. However, granular media display unusual behaviors that complicate the continuum treatment: they can behave like solid, flow like liquid, or separate into a “gas”, and the rheology of the flowing state displays remarkable subtleties.

To address these challenges, in this talk we develop a family of continuum models and numerical solvers, which permit quantitative modeling capabilities for general problems and certain reduced-order approaches for problems of intrusion, impact, driving, and locomotion in grains. To calculate flows in general cases, a rather significant nonlocal effect is evident, which is well-described with our recent nonlocal model accounting for grain cooperativity within the rheology. On the other hand, to model just intrusion forces on submerged objects, we will show, and explain why, many of the experimentally observed results can be captured from a much simpler tension-free frictional plasticity model. This approach gives way to some surprisingly simple general tools, including the granular Resistive Force Theory, and a broad set of scaling laws inherent to the problem of granular locomotion. These scalings are validated experimentally and in discrete particle simulations suggesting a new down-scaled paradigm for granular locomotive design, on earth and beyond, to be used much like scaling laws in fluid mechanics. We close with ongoing efforts expanding into wet granular flows, multi-scale approaches, and self-optimizing wheels for off-road traction.
Computations in Science

March 28, 2018
KPTC 206 | Wednesday, 12:15 pm

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Seppe Kuehn, University of Illinois at Urbana-Champaign

Constraints on eco-evolutionary dynamics in bacterial communities

Can we predict evolutionary and ecological dynamics in microbial communities? I argue that understanding constraints on biological systems provides a path forward to build predictive models. I present two vignettes which illustrate the power of elucidating constraints. First, we ask how constraints on phenotypic variation can be exploited to predict evolution. We select Escherichia coli simultaneously for motility and growth and find that a trade-off between these phenotypes constrains adaptation. Using genetic engineering, high- throughput phenotyping and modeling we show that the genetic capacity of an organism to vary traits can qualitatively depend on its environment, which in turn alters its evolutionary trajectory [eLife, 2017]. Our results suggest that knowledge of phenotypic constraints and genetic architecture can provide a route to predicting evolutionary dynamics. Second, in nature microbial populations are subjected to nutrient fluctuations but we know little about how communities respond to these fluctuations. Using automated long-term single cell imaging and custom continuous-culture devices we subject bacterial populations to nutrient fluctuations on multiple timescales._x000B_We find populations recover faster from large, frequent fluctuations. Our observation is explained by a model that captures constraints on the rate at which populations transition from planktonic and aggregated lifestyles.
Molecular Engineering

March 27, 2018
ERC 161 | Tuesday, 11:00 am

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Epistasis: the link between protein sequence and function

A new approach shows promise

Epstasis is the observed statistical correlation of mutations affecting a given protein.
A new approach shows promise

Come at noon to eat and talk
Discussion launch time 12:15
MRSEC Baglunch

March 23, 2018
GCIS E123 | Friday, 12:00 pm

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Bill Archer, Los Alamos Laboratory

Computing in the Los Alamos Weapons Program


Los Alamos has continuously been on the forefront of scientific computing since it helped found the field. This talk will explore the rich history of computing in the Los Alamos weapons program. The current status of computing will be discussed, as will the expectations for the near future.
Physics Colloquium

March 21, 2018
KPTC 106 | Wednesday, 4:00 pm

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March Meeting rehash: moiré graphene superconductivity, etc.

I hope you can make it to the baglunch tomorrow. If you went to the March meeting, I hope you'll bring your favorite tidbit to tell us about. One dramatic announcement was the report of superconductivity in a bilayer of graphene. How does that work?? Come with your daffiest ideas.

12:00 would be a great time to show up with your food if you don't want to miss anything
12:15 ---you won't miss too much.
MRSEC Baglunch

March 16, 2018
GCIS E123 | Friday, 12:00 pm

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Aleksandra Vojvodic, University of Pennsylvania

Computationally predicting chemistry of transition-metal compound materials

Fueling the planet with energy, chemicals and food are central challenges of the 21st century. Most materials we see in our everyday life have seen at one point or another a catalyst material of a complex nature. I will demonstrate how we today can computationally predict new catalyst materials through a careful analysis of the surface chemistry at the atomic-scale level enabled by access to advanced computational approaches.

I will present our studies on electrochemical water splitting including both of its subreactions: the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Computationally we have identified a new highly active two-dimensional (2D) transition-metal carbide HER catalyst and transition-metal oxide OER catalysts that have been experimentally synthesized, characterized and tested. The OER catalysts belong to the perovskite group of oxide materials or are oxides based on earth abundant metal elements. I will also share our recent insights on the reactivity and activity of metal-supported thin layers, nanoparticles of oxides and heterostructured oxide systems. Finally, I will discuss our recent findings on oxygen incorporation chemistry into non-stoichiometric oxides.

Molecular Engineering

March 15, 2018
ERC 201 | Thursday, 11:00 am

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Gediminas Juzeliūnas, Vilnius University, Lithuania

Synthetic spin-orbit coupling for ultracold atoms

Currently there is a great deal of activities in studying the spin-orbit coupling (SOC) for ultracold atoms. One of the challenges is to experimentally produce a two-dimensional (2D) SOC of the Rashba type, as well as a 3D Weyl SOC for the center of mass motion of ultracold atoms [1]. In particular, it was proposed that the 2D and 3D SOC can be generated by laser-dressing atomic internal states [1] or using a periodic sequence of magnetic gradient pulses [2]. Here we shall review these activities and also talk about the omnidirectional Spin-Hall effect [3] which can manifest for Weyl spin-orbit coupled ultracold atoms. We shall also discuss another way of creating the 2D SOC using ultracold atoms confined in bilayer structures [4-5]. An interplay between the inter-layer tunneling, intra-layer Raman coupling and intra-layer atom-atom interaction gives rise to an effective 2D SOC providing diverse ground-state configurations for bilayer Bose-Einstein condensates (BEC) [4] and degenerate Fermi gases [5].
JFI Special Seminar

March 14, 2018
KPTC 206 | Wednesday, 4:00 pm

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Roy Beck-Barkai , Tel-Aviv University

From kB to kB: Universal and efficient entropy estimation using a compression algorithm

Entropy and free-energy estimation are key in thermodynamic characterization of simulated systems ranging from spin models through polymers, colloids, protein structure, and drug-design. Current techniques suffer from being model specific, requiring abundant computation resources and simulation at conditions far from the studied realization. In this talk, I will present a novel universal scheme to calculate entropy using lossless compression algorithms and validate it on simulated systems of increasing complexity. Our results show accurate entropy values compared to benchmark calculations while being computationally effective. In molecular-dynamics simulations of protein folding, we exhibit unmatched detection capability of the folded states by measuring previously undetectable entropy fluctuations along the simulation timeline. Such entropy evaluation opens a new window onto the dynamics of complex systems and allows efficient free-energy calculations.
Computations in Science

March 14, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - Lutz Maibum, Department of Chemistry, University of Washington

Spatial Organization of Complex Lipid Bilayers: Emergent Order Across Multiple Scales

Cellular membranes are bilayers made of a large number of different types of phospholipids, sterols, and proteins. Their spatial organization is of fundamental importance for a large number of elementary biological processes including cell signaling and membrane trafficking. It has become clear that phospholipids and sterols contribute significantly to the lateral structure of such membranes. The order that emerges from their interactions spans multiple length scales, which necessitates the use of a wide range of models to study membrane organization with computational methods. In this talk I present our principal discoveries of membrane structure across multiple scales, including new aspects of the condensing effect of cholesterol, the rich phase behavior of multicomponent bilayers, and the effect of membrane fluctuations on protein interactions.


The Tuesday JFI Seminar

March 13, 2018
GCIS W301 | Tuesday, 4:00 pm

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Charles M. Lieber, Harvard University

Nanoelectronic Tools for Brain Science


Chemistry

March 12, 2018
Kent 120 | Monday, 4:00 pm

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Peter Schauss, Princeton University

Quantum gas microscopy of many-body dynamics in Fermi-Hubbard and Ising systems

The ability to probe and manipulate cold atoms in optical lattices at the atomic level using quantum gas microscopes enables quantitative studies of quantum many-body dynamics. While there are many well-developed theoretical tools to study many-body quantum systems in equilibrium, gaining insight into dynamics is challenging with available techniques. Approximate methods need to be benchmarked, creating an urgent need for measurements in experimental model  systems. In this talk, I will discuss two such measurements.
First, I will present a study that probes the relaxation of density modulations in the doped Fermi-Hubbard model. This leads to a hydrodynamic description that allows us to determine the conductivity. We observe bad metallic behavior that we compare to predictions from finite-temperature Lanczos calculations and dynamical mean field theory.
Second, I introduce a new platform to study the 2D quantum Ising model. Via optical coupling of atoms in an optical lattice to a low-lying Rydberg state, we observe quench dynamics in the resulting Ising model and prepare states with antiferromagnetic correlations.
JFI Special Seminar

March 12, 2018
KPTC 206 | Monday, 2:00 pm

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Chang-Tse Hsieh, IPMU

Symmetry-protected critical phases, generalized Lieb-Schultz-Mattis theorem, and global anomalies in (1+1) dimensions

The robustness of gaplessness in the presence of symmetries is one of the characteristics of the edge states of one-dimensional symmetry-protected topological (SPT) phases. These edge states, as the symmetries are realized in an on-site manner, can not exist alone and must arise on the boundary of one-higher dimensional SPT phases. This situation can, however, be circumvented for a 1d system with non-on-site symmetries, such as lattice translation symmetry, in the case that a nontrivial 2d bulk is absent. In this talk, I will discuss the quantum criticality in purely 1d lattice systems that is protected by translation symmetry together with some other on-site symmetries, from the perspective of ('t Hooft) anomaly matching. Examples include the charged fermions and SU(N) spin chains. The Lieb-Schultz-Mattis theorem, in the framework of field theory, is also re-derived and generalized.
Kadanoff Seminar

March 12, 2018
PRC 201 | Monday, 1:30 pm

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Liantao Wang

Future of Particle Physics: LHC and beyond


Particle physics entered a new era after the discovery of the Higgs boson. The Standard Model has left open many important questions, such as the origin of electroweak scale and identity of the dark matter. Searching for answers to these questions will be the main goal for particle physics in the decades to come. I will review the status of theoretical ideas and experimental searches for new physics, with focus on recent developments. I will also offer my perspective on possible future directions, including the next steps in the searches at the LHC, as well as other on-going and future experiments.
Physics Colloquium

March 8, 2018
KPTC 106 | Thursday, 4:00 pm

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Sean M. Gibbons, PhD, MIT

Individual-specific eco-evolutionary dynamics in the human gut microbiome

Dr. Gibbons will be hosted by BPHYS first-years, Vil Zsolnay and Elizabeth White.

Biophysical Dynamics

March 6, 2018
GCIS W301 | Tuesday, 12:00 pm

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JR Schmidt, University of Wisconsin-Madison

Physics-based force fields for next-generation accuracy and transability in molecular simulations

I will present a general methodology for generating accurate and transferable "physics-based" ab initio force fields for use in “next generation” molecular dynamics simulations. These force field models incorporate explicit terms to account for the dominant forces in (non-reactive) intermolecular interactions: exchange repulsion, electrostatics, polarization, and dispersion. This approach opens exciting possibilities for modeling chemical systems for which little or no experimental data exists. I will present a variety of applications, including those involving metal-organic framework materials, organic liquids, ionic liquids. The transferable nature of the force field models allows for their utilization for a wide variety of chemical systems. Building on that work, I will also present a number of recent developments that enable a significant increase in the accuracy of ab initio force fields via new approaches for modeling short-range Pauli repulsion and for capturing the local anisotropy of inter-atomic interactions (e.g. in the vicinity of a "lone pair"). These latter advances open up the possibility for even higher accuracy and transferability in a wide variety molecular simulation contexts.
Chemistry

March 5, 2018
Kent 120 | Monday, 4:00 pm

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Anatoly Dymarsky, University of Kentucky

Defining thermalization time

The conventional picture of how an isolated chaotic system thermalizes suggests that starting from a out of equilibrium state, the system reaches the equilibrium within Thouless time - the time necessary for the slowest (diffusive) mode to propagate across the whole system. Once that happened the system is expected to be fully ergodic i.e. its behavior should be independent of the initial conditions. It is in this regime a quantum system is expected to be described by a random matrix theory. Accordingly Thouless energy is usually associated with the energy scale of applicability of the random matrix description. In this talk we show that the conventional picture is too naive. By introducing a new characteristic of quantum systems which is sensitive to thermalization time, we show that the energy scale at which Eigenstate Thermalization Hypothesis ansatz reduces to the random matrix theory is parametrically different from the Thouless scale.
Kadanoff Seminar

March 5, 2018
PRC 201 | Monday, 1:30 pm

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Vincenzo Vitelli

From LEGO to Active Fluids


This colloquium offers a gentle introduction to the physics of topological materials using vivid mechanical demonstrations. The distinctive property of topological materials is the existence of states and excitations that are robust (or protected) against structural deformations, changes in material parameters or imperfections. We concentrate on two examples of topologically protected states: the folding motions of origami-like structures and sound propagation in active fluids composed of self-propelled particles. In both cases we trace the mathematical origin of physical robustness to elegant notions of topology.
Physics Colloquium

March 1, 2018
KPTC 106 | Thursday, 4:00 pm

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Dr. Tanay Roy, Tata Institute of Fundamental Research

Multi-mode Superconducting Circuits for Building Programmable Multi-qubit Quantum Processors

Quantum processors are capable of providing enormous speedup to certain problems by exploiting classically inaccessible paths. A vast majority of the small-scale quantum processors demonstrated so far in solid-state systems rely on the nearest-neighbor coupling. The limited connectivity and native gates restricted between two qubits hinder efficient implementation of many quantum algorithms. In this talk, I will introduce the “trimon” [1], a longitudinally coupled three-qubit system based on a multi-mode superconducting circuit. I will first describe how we can achieve universal programmability by utilizing elementary controlled-controlled-rotations and all-to-all connectivity. Reconstruction of the density matrix for an arbitrary three-qubit state is accomplished using a joint readout scheme. I will then discuss the performance of the single-pulse generalized Toffoli gates and the preparation of different two- and three-qubit entangled states. Another unique feature of this system is the ability to implement error-free CCZ gate [2] which simplifies the construction of various quantum oracles. I will demonstrate these capabilities by executing various quantum algorithms like Deutsch-Jozsa, Bernstein-Vazirani, Grover, quantum Fourier transform etc. on the three-qubit processor. Finally, I will discuss the possibility of building larger quantum processors using these longitudinally coupled multi-qubit systems.
JFI Special Seminar

March 1, 2018
ERC 201 | Thursday, 1:30 pm

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IME Distinguished Colloquium Series: Jeff Snyder, Northwestern University

Dislocation strain as the mechanism of phonon scattering at grain boundaries

For 50 years, we have commonly been using Casimir’s theory that describes the scattering of heat-carrying lattice vibrations (phonons) on the sample boundaries to also describe the reduction of thermal conductivity due to grain boundaries. In the frequency-independent Casimir model, phonons simply cannot travel across the boundaries, which is not the case in grain boundaries. This and a growing body of experimental and computational evidence shows that the modification of the Casimir model is necessary for grain boundaries. In this talk I will discuss our analysis of phonon scattering that controls the thermal conductivity of many common thermoelectric materials. We find that the grain boundary dislocation strain model can substitute for the Casimir model. More importantly, the two models can be distinguished at low temperature in fine-grained materials such that experimental evidence supports the grain boundary dislocation strain model. In this way, we suggest that grain boundaries themselves are best conceptualized as a collection of dislocations. Since strain and grain boundary structures can vary, we should be able to engineer grain boundaries or grain complexions (including extrinsic atoms) to disrupt phonon transport without harming electron transport.
Molecular Engineering

March 1, 2018
ERC 161 | Thursday, 11:00 am

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Michelle Driscoll, Northwestern University

Mind the gap: a cascade of instabilities created by rotating beads near a floor​

Does a rotating bead always spin in place? Not if that bead is near a surface: rolling leads to translational motion, as well as very strong flows around the bead, even quite far away. These flows strongly couple the motion of nearby microrollers (rotating beads), which leads to a rich variety of collective effects. Using experiments in tandem with large-scale 3D simulations, we have shown that driving a compact group of microrollers leads to a new kind of flow instability, whose wavelength is controlled not by the driving torque or the fluid viscosity, but a geometric parameter: the microroller's distance above the container floor. Furthermore, under the right conditions, stable, compact clusters we term "critters" can emerge from the unstable interface. Our simulations and experiments suggest that these critters are a stable state of the system, move much faster than individual rollers, and quickly respond to a changing drive. We believe that critters are unique in that they are clusters which form only with hydrodynamic interactions; no interparticle potentials are needed to create these structures. Furthermore, as compact, self-assembled structures which can easily be remotely guided, critters may offer a promising tool for microscopic transport.
Computations in Science

February 28, 2018
KPTC 206 | Wednesday, 12:15 pm

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Video Rate Atomic Force Microscopy Workshop

MRSEC and Asylum Research (Oxford Instruments)

This informative free workshop will include lectures and hands-on demonstrations for researchers who want to better understand how AFM can capture dynamic processes at the nanoscale. Topics will specifically cover video-rate AFM and the latest innovations for electrochemistry and nanomechanics / mechanobiology applications. The workshop is ideal for those that have AFM experience, as well as those who would like to learn more about incorporating AFM into their research. Registration is free, however, due to limited seating, all attendees must register.
MRSEC Workshop

February 28, 2018
ERC 201B | Wednesday, 9:00 am

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Bozhi Tian - Department of Chemistry - The University of Chicago

Physical Biology and Material Dynamics at Hard/Soft Interfaces

Although there are numerous studies on either hard or soft materials, our understanding of the fundamentals at hard/soft interfaces has been limited. As different types of energy (such as electrostatic, mechanical, thermal, and chemical energies) display diverse scaling behaviors and can converge, an appropriate selection of the length scale is critical for promoting new scientific discoveries across these interfaces. My group integrates material science with biophysics to study several hard/soft interfaces. We synthesize new materials and probe interfacial dynamics, with particular focus at the sub-micrometer and sub-cellular length scales. Our unique and extensive contributions have: (1) enabled non-genetic, freestanding, and semiconductor-based biological modulation; (2) revealed new dynamic aspects of liquid alloy droplets in semiconductor synthesis; and (3) exploited the dynamic behaviors of minerals or granular materials in polymeric matrices.
The Tuesday JFI Seminar

February 27, 2018
Kent 120 | Tuesday, 4:00 pm

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Toshikaze Kariyado, National Institute for Materials Science, Tsukuba

Designing Topological States in Graphene with Nano Holes

Gapping out Dirac cones in honeycomb lattice model has been playing key roles in finding new topological phases of matter, like Haldane’s seminal work on quantum anomalous Hall effect (QAHE) or Kane-Mele’s work on quantum spin Hall effect (QSHE). Note, however, that QAHE and QSHE require magnetism (time-reversal symmetry breaking) or spin-orbit coupling (SOC), respectively. A possible and magnetism/SOC free method to have finite gap in graphene is to introduce regularly aligned holes into a graphene sheet [1]. (Or, to make graphene antidot lattice, aka graphene nanomesh.) Here, we analyze the electronic structures of graphene nanomeshes in terms of topology [2]. Interestingly, it is found that a nanomesh where holes form triangular lattice and a nanomesh where holes form honeycomb lattice are topologically distinct with each other. The topological nontriviality is confirmed by explicitly calculating interface tates between the two regions of triangular and honeycomb nanomeshes, whose band structure has counterpropagating nature resembling to the one for helical edge states in QSH states. In addition to the interface state, we also diagnose the topology of the system by symmetry of the wave function, i.e., by a topological crystalline insulator viewpoint. It is demonstrated that the parity

index against 2D spatial inversion is a key quantity to detect topology in our system.
JFI/Kadanoff Joint Seminar

February 27, 2018
GCIS E123 | Tuesday, 2:00 pm

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Chad M. Rienstra, University of Illinois Urbana-Champaign

Molecular Fibrils and Sponges: Insights into Parkinson's Disease and Antifungal Drugs from NMR Spectroscopy

My research addresses fundamental questions about molecular structure and function of non-crystalline solids utilizing magic-angle spinning solid-state NMR spectroscopy along with a range of other chemical and biophysical methods. In this seminar, I will describe our recent results reporting the first high-resolution structure of full length alpha-synuclein fibrils, the protein most abundant in Lewy bodies and implicated in Parkinson’s disease propagation, and the mode of action of the antifungal drug amphotericin B, which binds and extracts sterols from lipid bilayers.
Chemistry

February 26, 2018
Kent 120 | Monday, 4:00 pm

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Vedika Khemani, Harvard University


Kadanoff Seminar

February 26, 2018
PRC 201 | Monday, 1:30 pm

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Sihong Wang, Postdoctoral Fellow, Department of Chemical Engineering, Stanford University

Merging Electronics with Living Systems: From Intrinsically Stretchable Materials and Devices to Mechanical Energy Harvesting

The vast amount of biological mysteries and biomedical challenges faced by human provide a prominent drive for seamlessly merging electronics with biological living systems (e.g. human bodies) to achieve long-term stable functions. Towards this trend, the main bottlenecks are the huge mechanical mismatch between the current form of rigid electronics and the soft biological tissues, as well as the limited lifetimes of the battery-based power supplies.

In this talk, I will first describe a new form of electronics with skin-like softness and stretchability, which is built upon a new class of intrinsically stretchable polymer materials and a new set of fabrication technology. As the core material basis, intrinsically stretchable polymer semiconductors have been developed through the physical engineering of polymer chain dynamics and crystallization based on the nanoconfinement effect. This fundamentally-new and universally-applicable methodology enables conjugated polymers to possess both high electrical-performance and extraordinary stretchability. Then, proceeding towards building electronics with this new class of polymer materials, the first polymer-friendly manufacturing process has been designed for large-scale intrinsically stretchable transistor arrays—the core device building-blocks for electronics. As a whole, these renovations in the material basis and technology foundation have led to the realization of circuit-level functionalities for the processing of biological signals, with unprecedented mechanical deformability and skin conformability. In the second part of the talk, I will introduce the invention and development of triboelectric nanogenerators as a new technology for mechanical energy harvesting, which provides a solution for sustainably powering electronics. The discussion will span from the establishment of basic operation mechanisms, the design strategies of material and device structure towards high energy conversion efficiency, to the hybridization with Li-ion batteries for effective energy storage. Equipping electronics with human-like form-factors and biomechanically-driven power supplies has opened a new paradigm for wearable and implantable bio-electronic tools for biological studies, personal healthcare, medical diagnosis and therapeutics.
Molecular Engineering

February 26, 2018
ERC 161 | Monday, 12:00 pm

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Pedro Lopes, Sherbrooke

Signatures of the chiral anomaly in phonon dynamics

The past decade of condensed matter physics has put a great weight in the importance of topological phenomena. Our particular interest here are Weyl semi-metals. Differently from its gapped insulating and superconducting topological cousins, the low-energy physics of Weyl semi-metals is not restricted to its surface, with bulk electronic properties being governed by linearly dispersing bands. An effective 3+1D Lorentz symmetry thus develops in these materials, settling Weyl semi-metals as prime candidates for comparative and analogue high-energy physics studies. In this context, we consider the phenomenon of the chiral anomaly, which in the high-energy context controls the decay rates of neutral pions into photons. In condensed matter, this phenomenon is traditionally understood to give rise to novel electronic transport phenomenology, whose verification, however, has been seen with controversy in the literature. To avoid such controversies, we present in this talk a detour from transport phenomena and show that optical properties of lattice oscillations carry singular signatures of the chiral anomaly. These come about by means of a novel type of polariton effect and are restricted only to certain classes of lattice oscillations in mirror symmetry broken Weyl semi-metals. Our proposed signatures of the condensed matter chiral anomaly then provide a robust alternative to transport while simultaneously constraining the systems to be studied, helping guide experimental efforts."
Kadanoff Seminar

February 23, 2018
PRC 201 | Friday, 1:30 pm

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Peng Liu, University of Pittsburgh

Computational Studies of Functionalization of C-H, C-C Bonds and Olefins


Chemistry

February 23, 2018
Kent 120 | Friday, 1:15 pm

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Hui Cao, Yale University

Mesoscopic Optics

Random scattering of light, e.g., in paint, cloud and biological tissue, is a common process of both fundamental interest and practical relevance. The interference of multiply scattered waves leads to remarkable phenomena in mesoscopic physics such as Anderson localization and universal conductance fluctuations. In applications, optical scattering is the main obstacle to imaging or sending information through turbid media. Recent developments of adaptive wavefront shaping in optics enabled imaging and focusing of light through opaque samples. By selective coupling to high or low transmission eigenchannels, we varied the transmission of a laser beam through a highly scattering system by two orders of magnitude, and drastically changed the energy density distribution inside the system. Furthermore, we utilized the multiple scattering of light in a random structure to realize a chip-scale spectrometer. The speckle pattern is used as a fingerprint to recover an arbitrary spectrum. Such a spectrometer has good spectral resolution and wide frequency range of operation.
Physics Colloquium

February 22, 2018
KPTC 106 | Thursday, 4:00 pm

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Xiaoyuan (Shawn) Chen, National Institute of Biomedical Imaging and Bioengineering

Cancer Nanotheranostics

Theranostics (Rx/Dx) aims to develop molecular diagnostic tests and targeted therapeutics with the goals of individualizing treatment by targeting therapy to an individual's specific disease subtype and genetic profile. It can be diagnosis followed by therapy to stratify patients who will likely respond to a given treatment; it can also be therapy followed by diagnosis to monitor early response to treatment and predict treatment efficacy; it is also possible that diagnostics and therapeutics are co-developed (nanotheranostics). This talk will give examples of how to assemble both inorganic and organic/polymeric materials for multimodality cancer imaging and drug/gene delivery.
Chemistry

February 21, 2018
Kent 120 | Wednesday, 3:00 pm

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Ivan I Smalyukh, University of Colorado Boulder

Topological Solitons and Other Knots in Soft Matter

Topologically nontrivial fields and vortices frequently arise in classical and quantum field theories, plasmas, optics, cosmology, hard condensed matter and atomic systems. On the other hand, soft matter systems, such as colloids and liquid crystals, offer the complexity in degrees of freedom and symmetries that allow for probing topologically analogous phenomena on experimentally accessible scales. In my lecture, I will discuss how surfaces of colloidal knots and handlebodies interact with the liquid crystalline molecular alignment fields and how topological knot solitons can emerge as static field configurations within the chiral colloidal ferromagnets [1-5]. I will show how such synergistic combinations of topology and self-assembly paradigms can emerge as an exciting scientific frontier of topological soft matter.
Computations in Science

February 21, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - Prof. Tzahi Cohen-Karni, Departments of Biomedical Engineering and Material Science & Engineering, Carnegie Mellon University

Multiscale Topological Design of Biological Interfaces to Novel Nanomaterials

My research team efforts focus on developing a new class of nanoscale materials and novel strategies for the investigation of biological entities at multiple length scales, from the molecular level to complex cellular networks. Our highly flexible bottom-up nanomaterials synthesis capabilities allow us to form unique hybrid-nanomaterials. Recently, we have demonstrated highly controlled synthesis of 3D out-of-plane single- to few-layer fuzzy graphene (3DFG) on a Si nanowire (SiNW) mesh template. By varying graphene growth conditions, we control the size, density, and electrical properties of the NW templated 3DFG (NT-3DFG). This flexible synthesis inspires formation of complex hybrid-nanomaterials with tailored optical and electrical properties to be used in future applications such as bio-sensing, and energy conversion and storage.
Our current efforts target the limits of cell-nanodevices interfaces using nanosensor based array assembled in 3D with subcellular spatial resolution (<5μm) and μsec temporal resolution. Our approach enables simultaneous multiplexed electrical measurements to directly monitor the development of electrical activities of microscale tissues (μtissues, ca. 100-400μm) which are engineered from induced pluripotent stem cell (iPS) derived cardiomyocytes or pancreatic islets isolated from mice. In summary, the exceptional synthetic control and flexible assembly of nanomaterials provide powerful tools for fundamental studies and applications in life science, and open up the potential to seamlessly merge either nanomaterials-based platforms or unique nanosensor geometries and topologies with cells, fusing nonliving and living systems together.Host: Bozhi Tian, 2-8749 or via email to btian@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
The Tuesday JFI Seminar

February 20, 2018
GCIS W301 | Tuesday, 4:00 pm

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Itamar Kimchi (MIT)

Valence Bond Entanglement in Random Quantum Magnets

Several longstanding problems in quantum magnetism concern quenched disorder. I will discuss the role of random exchange energies in spin-1/2 magnets where magnetic frustration promotes the formation of entangled valence bonds. With weak disorder we find that the destruction of a valence-bond solid phase leads inevitably to the nucleation of topological defects carrying spin-1/2 moments. This renormalizes the lattice into a strongly random network of defect spins which yields interesting low-energy excitations. With stronger disorder we find a related instability for a short-ranged valence bond glass. Motivated by these results we conjecture Lieb-Schultz-Mattis-type restrictions on ground states for disordered magnets with spin-1/2 per statistical unit cell. We apply this theoretical study to interpret experimental results on various spin-liquid-candidate magnets including YbMgGaO4 and H3LiIr2O6. Specific heat, susceptibility, thermal conductivity and dynamical structure factor, as well as their behavior in a magnetic field, are predicted and compare favorably with existing measurements. In particular I will show how recent observations of data collapse in T/H can be understood in terms of scaling laws derived from the theory.
Organizer: Kadanoff Center seminars
Kadanoff Seminar

February 20, 2018
PRC 215 | Tuesday, 1:30 pm

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Oleg Gang, Columbia University

Programmable Nano-Systems: Form Designed Architectures to Controllable Processes

Our ability to organize diverse type of nanoscale objects into the desired organizations is often a limiting factor in creating targeted nanomaterial. DNA provides powerful means for interaction encoding, and much progress was achieved recently by the field in ability to tailor DNA structures. However, it is challenging to prescribe the architecture or behavior of the entire nanoscale system as well as translate the advances of DNA assembly into material design. Our research explores novel concepts for creating targeted static and dynamic nano-architectures by bridging DNA-encoded nano-objects with structural plasticity and programmability of DNA macromolecular structures. Through establishing assembly approaches and revealing the phenomena that govern systems with DNA-encoded interactions, we develop methods for fabrication of well-defined three-dimensional lattices, two-dimensional membranes and finite-sized clusters from the multiple types of the nano-components. Our recent progress demonstrates strategy for organizing such nano-components as nanoparticles and proteins into ordered 3D arrays with engineered crystallographic symmetries, and clusters with prescribed architectures. These methods are also use to control a system dynamic behavior: structural transformation, specific triggering of desired configurations and molecular amplification. The applications of the DNA-based assembly platform for creation of optical and biomedical materials will be also discussed.
Chemistry

February 19, 2018
Kent 120 | Monday, 4:00 pm

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Dr. Benjamin Chapman, JILA-University of Colorado

Widely Tunable On-chip Microwave Circulator for Superconducting Quantum Circuits

This talk discusses the design and performance of a superconducting on-chip replacement technology for ferrite circulators. The device breaks Lorentz reciprocity--the symmetry, in an electrical network under exchange of source and detector--with sequential applications of frequency conversion and delay. As frequency and time are Fourier duals, translations in these quantities do not generally commute. A signal's port of entry may therefore be encoded in the time-ordering of the frequency conversion and delay operations. Design goals for the device are set for integration with superconducting quantum circuits, where the circulator enables the routing of propagating electromagnetic signals that encode the states of quantum systems. Given the current status of quantum error-correction and architectures for quantum information processing with superconducting circuits, such as scalable non-reciprocal devices will likely be necessary for construction of a superconducting quantum computer intended to be more than a proof-of-principle.
JFI Special Seminar

February 19, 2018
ERC 201 | Monday, 3:00 pm

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Greg Bentsen, Stanford University

Can We Make a Black Hole in the Lab?

The holographic principle tells us that certain gravitational systems, like black holes in AdS, are equivalent to conventional quantum many-body systems in one fewer dimension. A tantalizing possibility raised by this duality is the prospect of engineering artificial gravitational systems in the laboratory using controllable quantum-mechanical degrees of freedom such as cold atoms or trapped ions. Microscopic models of black holes, however, typically involve a number of exotic features, such as random infinite-range all-to-all couplings and strong chaotic behavior that are difficult to implement in experimental setups. In particular, since black holes are the fastest scramblers in nature, any quantum system that purports to contain an artificial black hole must scramble information at or near the Maldacena-Shenker-Stanford chaos bound. These are formidable challenges, but I will show in this talk how we are making progress toward being able to both simulate and measure systems that exhibit some of these characteristic features in the laboratory. While we are still a long way from being able to look behind event horizons or see artificial Hawking radiation, these preliminary efforts point favorably toward implementations of artificial gravity in the future, and in the meantime should prove useful for experimental studies of exotic many-body dynamics, closed-system thermalization, and quantum chaos.
Kadanoff Seminar

February 19, 2018
PRC 201 | Monday, 1:30 pm

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Professor Alison Fout, University of Illinois at Urbana-Champaign

Ligand Influences on Base Metals for Multi-Electron Transformations

Multi-electron transformations featuring base metals are both particularly challenging and interesting. A series multi-dentate ligand frameworks containing both hydrogen bond donating and accepting moieties in the secondary coordination sphere have been synthesized and reactivity will be described. These transformations feature the reduction of inorganic oxyanions which have long been touted for their inertness since these species are generally considered to be non-complexing anions, poor nucleophiles and kinetically inert to oxidation and reduction. Likewise, using a strong-field bis(carbene) ligand platform we have been able to demonstrate two-electron redox reactions on both cobalt and nickel complexes to access relatively rare organometallic species that are capable of a variety of catalytic transformations.
Chemistry

February 16, 2018
Kent 120 | Friday, 1:15 pm

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How can more ions in a liquid give less ionic screening?

Bring food at noon
Hear puzzle at 12:15
MRSEC Baglunch

February 16, 2018
GCIS E123 | Friday, 12:00 pm

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Paul McEuen, Cornell University

The Future of Small

Fifty years ago, the Nobel Prize-winning physicist Richard Feynman claimed that a revolution was underway where information, computers, and machines would be shrunk to impossibly small dimensions. History has proven him mostly right: Moore’s law has brought Feynman’s dreams to fruition in the realms of data and computing, giving us cell phones, the internet, and artificial intelligence. But the third leg of Feynman’s dream, the miniaturization of machines, is only just getting underway. Can we create functional, intelligent machines at the smallest scales? And if so, how? In this talk, I’ll take a look at some of the approaches being explored, including our group’s forays into combining electronics, paper arts, and functional 2D materials to create a new generation of smart, active nanomachines.
Physics Colloquium

February 15, 2018
KPTC 106 | Thursday, 4:00 pm

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Joaquin Rodriguez-Lopez, University of Illinois

Titrating Reactive Intermediates at Operating Water-Splitting Photoanodes: Elucidating Spatial, Temporal, and Chemical Heterogeneitie

Chemical transformation at the semiconductor/electrolyte interface for processes in energy, water remediation, and catalysis is enabled by the complex interplay of photogenerated charge carriers and surface chemical intermediates. I will describe unique electroanalytical tools developed in my laboratory for quantifying chemical processes and intermediates on water oxidation (photo)anodes with high temporal and spatial resolution, as well as chemical specificity. Our powerful toolset is based on scanning electrochemical microscopy (SECM). Using a combination of product collection modes (O2, H2O2), redox mediator-based measurements, and transient redox titrations we are gaining quantitative insight into the role of local perturbations in conditioning, controlling and encoding reactivity on photoelectrochemical interfaces. My discussion will include the inspection of electrode processes on wide-bandgap and solar photoelectrodes, as well as in nano-patterned surfaces and electrocatalysts. New in situ methods capable of approaching the surface dynamics of operating photocatalysts are required to provide a new leap in the design of photochemical interfaces for important processes in water environmental and energy applications.
Molecular Engineering

February 15, 2018
ERC 201 | Thursday, 11:00 am

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Paul McEuen, Cornell University

Listening to a thermal guitar: Hearing (and seeing) the vibrations of a carbon nanotube

Carbon nanotubes reside at the boundary of macroscopic mechanics and polymer physics. They can be made into guitar-string resonators and operated in vacuum, yet they are flexible enough that thermal fluctuations completely alter their properties. Here we show that individual carbon nanotubes can be picked up and strained with micron-sized tweezers, allowing us to study these novel fluctuating strings in a variety of new ways. Experiments include recording the “sound” of the thermal vibrations of a nanotube and “seeing” its real-time motion with light. We find many surprising results, including strong coupling between vibrational modes and very long intrinsic dissipation times, as well as many unresolved mysteries. These results open the door to the science of thermally-fluctuating strings in the underdamped limit, with many opportunities for theory, computation, and experiment.
Computations in Science

February 14, 2018
KPTC 206 | Wednesday, 12:15 pm

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Boris Spivak, University of Washington

Anomalous metals-failed superconductors

The observation of metallic ground states in a variety of two-dimensional electronic systems poses a fundamental challenge for the theory of electron fluids. I willl analyze evidence for the existence of a regime, which we call the anomalous metal regime," in diverse 2D superconducting systems driven through a quantum superconductor to metal transition by tuning physical parameters such as the magnetic field,the gate voltage in the case of systems with a MOSFET geometry, or the degree of disorder. The principal phenomenological observation is that inthe anomalous metal,as a function of decreasing temperature, the resistivity first drops as if the system were approaching a superconducting ground state, but then saturates at low temperatures toa value that can be orders of magnitude smaller than the Drude value. The anomalous
metal also shows a giant positive magneto-resistance. Thus, it behaves as if it were a failed superconductor." This behavior is observed in a broad range of parameters. We moreover exhibit, by theoretical solution of a model of superconducting grains embedded in a metallic matrix, that as a matter of principle such anomalous metallic behavior can occur in the neighborhood of a quantum superconductor-metal transition. However,
we also argue that the robustness and ubiquitous nature of the observed phenomena are dicult to reconcile with any existing theoretical treatment, and speculate about the character of a more fundamental theoretical framework.
Kadanoff Seminar

February 13, 2018
PRC 201 | Tuesday, 1:30 pm

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Marcos González-Gaitán, PhD, University of Geneva

Asymmetric signaling endosomes in asymmetric division

Sandwiches at 11:45; remember to bring a cup for coffee or tea.
Biophysical Dynamics

February 13, 2018
GCIS W301 | Tuesday, 12:00 pm

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Professor William Shih, Harvard University

DNA-origami Barrels

DNA origami, in which a long scaffold strand is assembled with a large number of short staple strands into parallel arrays of double helices, has proven a powerful method for custom nanofabrication. Although diverse shapes in 2D are possible, the single-layer rectangle has proven the most popular, as it features fast and robust folding and modular design of staple strands for simple abstraction to a regular pixel surface. Here we introduce a barrel architecture, built as stacked rings of double helices, that retains these appealing features, while extending construction into 3D. We demonstrate hierarchical assembly of a 100 megadalton barrel that is ~90 nm in diameter and ~270 nm in height, and that provides a rhombic-lattice canvas of a thousand pixels each, with a pitch of 9 nm, on its inner and outer surfaces. Complex patterns rendered on these surfaces were resolved using up to twelve rounds of exchange PAINT super-resolution fluorescence microscopy. We envision these structures as versatile nanoscale pegboards for applications requiring complex 3D arrangements of matter.

Persons with a disability may call (773)795-5843 in advance for assistance.

Chemistry

February 12, 2018
Kent 120 | Monday, 4:00 pm

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Rifts in Rafts: the fracture of monolayers on fluid interfaces

Eat 12:00
Talk 12:15
MRSEC Baglunch

February 9, 2018
GCIS E123 | Friday, 12:00 pm

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Nadya Mason, The University of Illinois at Urbana-Champaign

In Proximity to Novel Physics: Topological Insulators coupled to Superconductors


Topological insulators (TI’s) are materials that are insulators in their interiors, but have unique conducting states on their surfaces. They have attracted significant interest as fundamentally new electronic phases having potential applications from dissipationless interconnects to quantum computing. In particular, coupling the surface state of a TI to an s-wave superconductor is predicted to produce the long-sought Majorana quasiparticle excitations, which could play a role in solid-state implementations of a quantum computer. A requisite step in the search for Majorana fermions is to understand the nature and origin of the supercurrent generated between superconducting contacts and a TI. In this talk, I will discuss TI-superconductor junctions, focusing on transport measurements taken as the chemical potential is moved from the bulk bands into the band gap, or through the true topological regime characterized by the presence of only surface currents.
Physics Colloquium

February 8, 2018
KPTC 106 | Thursday, 4:00 pm

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Eric Hudson, University of California, Los Angeles

Zen and the Art of Atomic Physics

In the Ten Bulls tradition, the fifth stage of Zen is reached when the practitioner has caught and tamed the wild bull. This is roughly the state of atomic physics. The atom has been tamed. It can be prepared in a single quantum state, its evolution coherently controlled, and its entanglement generated at will. As such, many new quantum-assisted technologies and fundamental physics measurements have resulted and a quantum revolution is well underway that promises to touch almost every aspect of our lives. By the seventh stage of Zen, the Bull has transcended and is no more. This again may be paralleled in atomic physics as the atom is being replaced with richer quantum systems such as molecules, whose internal degrees of freedom provide new oppurtunities for quantum science and technology.
In this talk, I will briefly review the science and technology that have come from atom taming and then discuss our efforts to tame other bulls: polar molecular ions and atomic nuclei.

Molecular Engineering

February 8, 2018
ERC 201 | Thursday, 11:00 am

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Haim Diamant, Tel Aviv University

Hyperuniform dynamic structures of forced colloids

Several materials have been found in recent years to exhibit "hyperuniformity", their constituent particles being distributed in a disordered but correlated configurations such that density fluctuations are strongly suppressed. Examples are sheared suspensions and emulsions, and random jammed packings of particles. In those systems the hyperuniform structure appears as a static absorbing state. Suppression of density fluctuations appears also in thermodynamic and dynamic systems which sample many spatial configurations. Examples are electrolytes and suspensions of forced colloids. We relate the statistical hyperuniformity in these systems to conservation laws and long-range interactions. We demonstrate in detail the suppression of density and velocity fluctuations in forced suspensions of asymmetric objects. In this case we have identified the basic mechanism leading to hyperuniformity. We argue that for certain object shapes the same mechanism can act in the opposite direction, destabilizing the dynamics.
Computations in Science

February 7, 2018
KPTC 206 | Wednesday, 12:15 pm

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The 1st Tuesday JFI Colloquium - CLOSS LECTURE - Prof. Jonathan A. Rogers, Department of Chemistry, Simpson/Querrey Institute - Northwestern University

Materials for Bioresorbable Electronics

A remarkable feature of modern integrated circuit technology is its ability to operate in a stable fashion, with almost perfect reliability, without physical or chemical change. Recently developed classes of electronic materials create an opportunity to engineer the opposite outcome, in the form of devices that can dissolve in water to yield completely benign end products. The enabled applications include zero-impact environmental monitors, 'green' consumer electronics and temporary biomedical implants - none of which is possible with technologies that exist today. This talk describes foundational concepts in chemistry, materials science and assembly processes for bioresorbable electronics in 2D and 3D architectures, the latter enabled by approaches that draw inspiration from the ancient arts of kirigami and origami. Wireless sensors of intracranial temperature, pressure and electrophysiology designed for use in treatment of traumatic brain injury and nerve stimulators as ‘electronic medicines’ for accelerated neuroregeneration provide application examples.For further information please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu. You may also contact the Host, Valerii Sharapov at 773-610-7726 or via email to sharapov@uchicago.edu.
The 1st Tuesday JFI Colloquium

February 6, 2018
GCIS W301 | Tuesday, 4:00 pm

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Etienne Caron, ETH Zurich

Decoding cancer antigenomes by SWATH-MS for effective immunotherapies

Over the past years at ETH-Zurich, Switzerland, I have contributed to the development of an innovative mass spectrometry (MS) technology, known as SWATH-MS, which enables robust quantitative measurements of proteins and MHC-associated peptides across large sample cohorts. During this seminar, I will show how a similar technology has been successfully deployed to demonstrate that tumor-specific neoantigens do exist as physical molecules in cancer and represent key targets of T cells in response to checkpoint immunotherapy. In addition, I will show how SWATH-MS permits quantification of protein interaction dynamics in primary T cells. Finally, I will present my long-term vision and how to take MS technology towards highly precise and efficient cancer immunotherapies.
Molecular Engineering

February 5, 2018
ERC 161 | Monday, 11:00 am

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Dr. Monika Aidelsburger, Ludwig-Maximilians-Universität München

Floquet engineering with ultracold atoms in optical lattices

Floquet engineering is an important tool for the engineering of novel band structures with interesting properties that go beyond those offered by static systems. Recently, Floquet systems have enabled the generation of Bloch bands with non-trivial topological properties, such as the Hofstadter and Haldane model. This led to the observation of chiral Meissner currents and the first Chern-number measurements with charge-neutral atoms.


Besides this success studies of many-body phases in driven systems remains experimentally challenging in particular due to the interplay between periodic driving and interactions. In a driven system energy is not conserved which can lead to severe heating. In order to find stable parameter regimes for the generation of driven many-body phases it is essential to develop a deeper understanding of the underlying processes.


In this talk, I briefly review recent experimental advances in the generation of topological band structures in the non-interacting regime using Floquet engineering and present first studies of interacting atoms in driven 1D lattices.
JFI Special Seminar

February 2, 2018
KPTC 106 | Friday, 1:30 pm

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Professor Ian Tonks, University of Minnesota - Twin Cities

Ti-Catalyzed Nitrene Transfer Reactions: Harnessing the TiII/TiIV Redox Couple for New Organic Methods

Titanium is an ideal metal for green and sustainable catalysis—it is the 2nd most earth-abundant transition metal, and the byproducts of Ti reactions (TiO2) are nontoxic. However, a significant challenge of utilizing early transition metals for catalytic redox processes is that they typically do not undergo facile oxidation state changes because of the thermodynamic stability of their high oxidation states. We have recently discovered that Ti imidos (LnTi=NR) can catalyze oxidative nitrene transfer reactions from diazenes via a TiII/TiIV redox couple, and are using this new mode of reactivity to develop a large suite of practical synthetic methods. In this talk, our latest synthetic and mechanistic discoveries related to Ti nitrene transfer catalysis will be discussed, including new synthetic methods for the modular, selective construction of pyrroles via [2+2+1] cycloaddition of alkynes with Ti nitrenes and alkynes, as well as new methods for catalytic oxidative carboamination of other unsaturated organics by Ti nitrenes.
Chemistry

February 2, 2018
Kent 120 | Friday, 1:15 pm

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Molecular motors force themselves into "stacks"; does this help?

Bring food at noon.
Story time starts at 12:15
MRSEC Baglunch

February 2, 2018
GCIS E123 | Friday, 12:15 pm

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Dan Holz, The University of Chicago

GW170817: Hearing and seeing a binary neutron star merger

With the discovery of GW170817 in gravitational waves, and the discovery of an associated short gamma-ray burst, and the discovery of an associated optical afterglow, we have finally entered the era of gravitational-wave multi-messenger astronomy. I will discuss LIGO/Virgo's detection of this binary coalescence, and explore some of the scientific implications, including confirmation of the kilonova model and implications for the origin of gold and platinum in the universe, tests of general relativity, and the first standard siren measurement of the Hubble constant. GW170817 represents a momentous development in gravitational-wave astronomy, and the birth of gravitational-wave cosmology.
Physics Colloquium

February 1, 2018
KPTC 106 | Thursday, 4:00 pm

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IME Distinguished Colloquium Series: Naomi Halas, Rice University

Plasmonics: from noble metals to sustainability

Metallic nanoparticles, used since antiquity to impart intense and vibrant color into materials, have more recently become a central tool in the nanoscale manipulation of light. This interest has led to a virtual explosion of new types of metal-based nanoparticles and nanostructures of various shapes and compositions, and has given rise to new strategies to harvest, control, and manipulate light based on metallic nanostructures and their properties. As one begins to assemble metallic nanoparticles into useful building blocks, a striking parallel between the plasmons- the collective electronic oscillations- of these structures and wave functions of simple quantum systems is universally observed. Clusters of metallic nanoparticles behave like coupled oscillators, introducing effects characteristic of systems as diverse as radio frequency transmitters and coupled pendulums into light-driven nanoscale structures. Plasmons decay by producing hot electrons, a property appearing to be highly useful in applications ranging from photodetection to photocatalysis. In particular, new “antenna-reactor” photocatalysts can be designed by combining plasmonic nanoparticles with directly adjacent catalytic particles or materials, rendering the heterocomplexes photocatalytic. While our scientific foundation for the field of Plasmonics has been built on nanoparticles consisting of noble and coinage metals, more recently we have begun to question whether the same, or similar, plasmonic properties can also be realized in more sustainable materials. Aluminum, the most abundant metal on our planet, can support high-quality plasmonic properties across the visible region of the spectrum, enabling practical large-area and cost-effective plasmonic applications such as flat-panel displays, robust colorimetric sensors, and selective ethylene synthesis. Graphene is an outstanding active plasmonic material, however, it can be tuned from the infrared into the visible region of the spectrum only by miniaturization to the true molecular limit. Sustainable plasmonic materials allow us to envision entirely new applications, for example, direct solar distillation that can provide drinkable water, entirely independent of grid-based electrical power.
Molecular Engineering

February 1, 2018
ERC 161 | Thursday, 11:00 am

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Jens Eggers , University of Bristol

Pair creation, motion, and annihilation of topological defects in 2D nematics

We present a novel framework for the study of disclinations in two-dimensional active nematic liquid crystals, and topological defects in general. The order tensor formalism is used to calculate exact multi-particle solutions of the linearized static equations inside a planar uniformly aligned state, so that the total charge has to vanish. Topological charge conservation then requires that there is always an equal number of $q=1/2$ and $q=-1/2$ charges. Starting from a set of hydrodynamic equations, we derive a low-dimensional dynamical system for the parameters of the static solutions, which describes the motion of a half-disclination pair, or of several pairs. Within this formalism, we model defect production and annihilation, as observed in experiments. Our dynamics also provide an estimate for the critical density at which production and annihilation rates are balanced.
Computations in Science

January 31, 2018
KPTC 206 | Wednesday, 12:15 pm

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The Tuesday JFI Seminar - Prof. Michael Hagan, Department of Physics and Quantative Biology, Brandeis University

Unexpected Ordered Phases in Active Matter

Active matter describes systems whose constituent elements consume energy to generate motion, and are thus intrinsically far-from equilibrium. I will describe computer simulations of two recently developed active matter systems. (1) Self-propelled colloids with repulsive interactions and no aligning interactions are a minimal model active matter system. We and others have shown that, even when particles experience only repulsive interactions, this system undergoes a phase coexistence that mimics the equilibrium phase separation of attractive colloids. I will present a simple kinetic theory that describes the dynamics of phase separation, resulting in a framework analogous to equilibrium classical nucleation theory. (2) Active nematics are liquid crystals which are driven out of equilibrium by energy-dissipating active stresses. The ordered nematic state is unstable to the proliferation of topological defects, which undergo birth, streaming dynamics, and annihilation to yield a seemingly chaotic dynamical steady-state. In this talk, I will show that order emerges from this chaos, in the form of heretofore unknown broken-symmetry phases in which the topological defects themselves undergo orientational ordering. Time permitting, I will also show that active nematics are remarkable insensitive to topological constraints even under high confinement
The Tuesday JFI Seminar

January 30, 2018
GCIS W301 | Tuesday, 4:00 pm

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Professor Anna Mapp, University of Michigan

From Fuzzy to Function in Gene Activation

Within the chemical space of protein-protein interactions (PPIs), transient, modest affinity PPIs play a central role in a variety of cellular functions, including protein folding and transcription. Dysregulation of this class of PPIs is at the heart of diseases ranging from cancer to neurodegenerative disorders. For example, in several types of AML, leukemogenesis is dependent upon the loss of one transcriptional activator-coactivator interaction (MLL-p300) and the maintenance or amplification of a second (cMyb-p300). Despite their importance and their prevalence, such transient and modest affinity PPIs are often classified as ‘undruggable’, with few successful strategies for small molecule modulator discovery. A significant challenge has been that the binding partners often have significant disorder and are thus difficult to characterize structurally alone or in complex. A strategy for the identification of chemical co-chaperones that capture particular conformations of transcriptional coactivators and in doing so selectively modulate the assembly of transcriptional activator-coactivator complexes in vitro and in cells will be described.
Chemistry

January 29, 2018
Kent 120 | Monday, 4:00 pm

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Professor David J. Michaelis, Brigham Young University

Synthetic Applications of Enzyme-Inspired Catalysts

Our research program is focused on using nature as an inspiration for the development of novel catalytic tools for organic synthesis. In the active site of enzymes, multiple metal centers often cooperate to lower the barrier to oxidative and reductive processes, thus enabling efficient catalysis in very challenging organic transformations. Our group is designing and developing heterobimetallic catalysts where metal-metal interactions and cooperativity can lead to enhanced catalysis and novel transformations. Our efforts have led to the development of Pd–Ti and Pt–Ti catalysts that display exceptional reactivity in allylic amination and cycloisomerization reactions respectively. This seminar will describe our current efforts to develop chiral Ti–M complexes for enantioselective catalysis and heterobimetallic M–Ni complexes for nickel catalysis applications. In separate pursuits, we have also developed peptide-based multifunctional catalysts that enable enzyme-like cooperative catalysis. The small peptide scaffold brings multiple non-natural catalysts into close proximity, enabling faster catalyst turnover, novel selectivity based on substrate binding and proximity, and the development of novel two-catalyst transformations. The development and use of these catalysts to achieve novel reaction rates and selectivity and for new reaction discovery will also be presented.
Chemistry

January 26, 2018
Kent 120 | Friday, 1:00 pm

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how curved creases turn flat sheets topological

Bring food at noon.
Story time starts at 12:15
MRSEC Baglunch

January 26, 2018
GCIS E123 | Friday, 12:15 pm

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Jia Liu, Shriram Center for Bioengineering and Chemical Engineering, Department of Chemical Engineering, Stanford University

Soft bioelectronics for tissue and organ interfaces: from tissue-like electronics to genetically-targeted biosynthetic electrodes

Rapid progress in soft materials and electronics has blurred the distinction between man-made devices and biological systems. Seamless integration of electronic devices with living systems could contribute substantially to basic biology as well as to clinical diagnostics and therapeutics through tissue-electronics interfaces. In this presentation, I will first introduce a syringe-injectable tissue-like mesh electronics for merging soft nanoelectronic arrays and circuits with the brain in three-dimension (3D). The injectable mesh electronics has micrometer feature size and effective bending stiffness values similar to neural tissues. These unprecedented features lead to the gliosis-free and 3D interpenetrated electronics-neuron network, enabling the chronically stable neuron activity recording at single-neuron resolution in behaving animals. Second, I will describe a fully stretchable electronic sensor array through the development of multiple chemically-orthogonal and intrinsically stretchable polymeric electronic materials. The fully stretchable sensor array has modulus similar to biological tissues, allowing an intimate mechanical coupling with heart for a stable and anatomically precise electrophysiological recording. Its application for high-throughput and high-density mapping of 3D cardiac arrhythmogenic activities on the porcine model with a chronic atrial fibrillation will be discussed. Third, I will present a fundamentally new approach for a direct formation of electrical connections with genetically-targeted cells. This approach is accomplished through the convergence of genome engineering, in situ enzymatic reaction and polymer chemistry. These genetically-targeted electrodes are inherently assembled to the subcellular-specific region of neurons throughout the intact functional neural tissue and in stem cell-derived human brain organoids. Importantly, this system also enables the cellular-resolution tuning of local neuronal activity and bridging of brain regions to external devices for the targeted recording. Finally, I will briefly discuss the prospects for future advances in soft bioelectronics to overcome challenges in neuroscience and cardiology through the development of “cyborg animals” with single-cell resolution and cell-type specificity.
Molecular Engineering

January 25, 2018
ERC 161 | Thursday, 11:00 am

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Alberto Fernandez-Nieves, Georgia Tech

Fire-ant fluids: expansion, mechanics and waves

Motivated by classic thermodynamic experiments with dilute fluids, we explore the free and constrained expansion of fire-ant aggregations. In the latter case, we confine the ants to 2D vertical columns; hence, as the ants expand, they do work against the gravitational field. Surprisingly, we often observe the spontaneous generation of density waves; these propagate at a speed that depends on both the width and the amplitude of the wave, and occur cyclically. We also perform experiments in horizontal cells and find that the ants exhibit activity cycles, where the density homogeneity and mechanical properties of the aggregation change with activity. We believe that these cycles together with the large ant densities in our vertical columns are responsible for the generation of the observed waves. Finally, since the average ant density is larger at the bottom of the vertical column than a the top, we follow our temptation and attempt at interpreting the results in lieu of sedimentation equilibrium to seek for an equation of state. Despite our results are still highly preliminary, they provide interesting phenomenology that could perhaps be seen in active systems other than fire-ant aggregations.
Computations in Science

January 24, 2018
KPTC 206 | Wednesday, 12:15 pm

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Prof. Anders Niklasson, Los Alamos National Laboratory, Theoretical Division

Next Generation Quantum Based Molecular Dynamics

Quantum based molecular dynamics (QMD) simulations provide a highly powerful, but computationally expensive, multidisciplinary tool to predict, understand and design materials and processes directly from the first principles of quantum physics. QMD simulations ideally represent an almost universal approach to study a wide range of problems in chemistry, molecular biology and materials science. Merging QMD with future extreme-scale computing holds the promise of a major paradigm shift in computer-driven science. Unfortunately, this potentially revolutionary opportunity will never be realized without a radical re-design of established QMD simulation schemes to overcome a number of interconnected fundamental problems. Over the last decade we have worked on the development of a new generation QMD that avoids several computational bottlenecks and obstacles inherent to previous methods. For the first time, QMD simulation is now emerging as a practically feasible approach in simulations of +100,000 atoms — representing a competitive alternative to classical polarizable force field models. I will present the background and the underlying theoretical framework as well as future challenges and opportunities.
The Tuesday JFI Seminar

January 23, 2018
GCIS W301 | Tuesday, 4:00 pm

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Po-Chun Hsu, Postdoctoral Researcher, Department of Mechanical Engineering, Stanford University

Light- and Heat-Managing Nanomaterials for Personal Health and Energy Efficiency

In this talk, I will present several nanomaterials that can manage photons and heat transfer to enhance building energy efficiency and personal health in an unconventionally effective way. The first part introduces the concept of personal thermal management. Personal thermal management focuses on controlling the temperature around the human body rather than the whole space, so it can provide the same thermal comfort with lower energy demand and shorter turnaround time. For passive personal thermal management, i.e., no additional energy input, the key parameter is the heat transfer coefficient of the clothing. Thermal radiation, as the dominant heat transfer pathways for the indoor scenario, is an extremely effective yet less explored tuning knob. I will demonstrate infrared-reflective metallic nanowires textile for heating and infrared-transparent nanoporous polyethylene (nanoPE) for cooling, both of which achieve superior heating/cooling properties than traditional textiles. The nanoPE textile is further used to fabricate the dual-mode textile that can switch between heating and cooling modes by reversing the textile. This interesting dual-modality can expand the wearers’ adaptability to ambient temperature fluctuation to maintain thermal comfort and potentially prevent cardiovascular and respiratory diseases. The second part introduces transparent electrodes and electrochromic windows. The transparent electrode is the key component for many optoelectronic devices, including photovoltaic cells, touchscreen displays, and smart windows. Transparent electrodes with both high optical transparency and low electrical resistance will greatly benefit the device performances. For building energy efficiency, smart windows are capable of changing its color to control solar heat gain by applying only a few volts of electricity, and the energy demand for indoor temperature control can be reduced. I will introduce metal nanofiber transparent electrodes with the superior electrical and optical properties and durability which can achieve electrochromic windows with high switching speed, mechanical bendability, and long cycle life. Fabricated by electrospinning and various metallization techniques, the metal nanofibers are infinitely long and well-connected and have minimal wire-to-wire junction resistance.
Molecular Engineering

January 23, 2018
ERC 201B | Tuesday, 11:00 am

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Professor Hanadi Sleiman, McGill University

DNA Nanostructures for Cellular Delivery of Therapeutics

DNA nanotechnology can assemble materials on the nanoscale with exceptional predictability and programmability. In a sense, this field has reduced the self-assembly space into a simple ‘language’ composed of four letters (A, T, G, C). Nature, on the other hand, relies on many more supramolecular interactions or ‘languages’ to build its functional structures. Over the last 50 years, supramolecular chemistry has taken advantage of these interactions to assemble materials with highly diverse structures and functions.

This talk will describe our efforts to merge the field of supramolecular chemistry with DNA nanotechnology. This approach results in new motifs and functionalities that are unavailable with base-pairing alone. Starting from a minimum number of DNA components, we create 3D-DNA host structures, such as cages, nanotubes and micelles, that are promising for targeted drug delivery. These can encapsulate and selectively release drugs and materials, and accomplish anisotropic 3D-organization. We find that they resist nuclease degradation, silence gene expression to a significantly greater extent than their component oligonucleotides and have a favorable in vivo distribution profile. We designed a DNA cube that recognizes a cancer-specific gene product, unzips and releases drug cargo as a result, thus acting as a conditional drug delivery vehicle, as well as DNA structures that bind to plasma proteins with low nanomolar affinities.

We will also describe a method to ‘print’ DNA patterns onto other materials, thus beginning to address the issue of scalability for DNA nanotechnology. Finally, we will discuss the ability of small molecules to reprogram the assembly of DNA, away from Watson-Crick base-pairing and into new motifs.

Persons with a disability may call (773) 795-5843 in advance for assistance.

Chemistry

January 22, 2018
Kent 120 | Monday, 4:00 pm

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Fengcheng Wu, Argonne National Lab

Theory on nematic odd-parity superconductivity

Topological superconductors represent a paradigmatic system where topological effects and many-body interactions can have an interesting interplay. Various recent experiments have indicated that superconductivity in CuxBi2Se3 and related materials is nematic with rotational symmetry breaking. This nematic superconductivity is consistent with an odd-parity pairing. Therefore, CuxBi2Se3 is a strong candidate for time-reversal invariant topological superconductor. In this talk, I will discuss our theoretical work on nematic odd-pa