Professor Xavier Roy, Columbia University
Molecular Clusters: Building Blocks for Nanoelectronics and Material Design
Two shades of forced wettingEat: high noon
Talk: high 12:15
Melissa Franklin, Harvard University
Dear Maria, Oh My, How Particle Physics has Changed
Juan De Pablo, University of Chicago, IME
Emerging Insights into Directed Assembly: Taking Examples from Nature to Design Synthetic ProcessesThere is considerable interest in controlling the assembly of polymeric material in order to create highly ordered materials for applications. Such materials are often trapped in metastable, non-equilibrium states, and the processes through which they assemble become an important aspect of the materials design strategy. An example is provided by di-block copolymer directed self-assembly, where a decade of work has shown that, through careful choice of process variables, it is possible to create ordered structures whose degree of perfection meets the constraints of commercial semiconductor manufacturing. As impactful as that work has been, it has focused on relatively simple materials – neutral polymers, consisting of two or at most three blocks. Furthermore, the samples that have been produced have been limited to relatively thin films, and the assembly has been carried out on ideal, two-dimensional substrates. The question that arises now is whether one can tra! nslate th ose achievements to polymeric materials having a richer sequence, to monomers that include charges, to three-dimensional substrates, or to active systems that are in a permanent non-equilibrium state. Building on discoveries from the biophysics literature, this presentation will review recent work from our group and others that explains how nature has evolved to (1) direct the assembly of nucleic acids into intricate, fully three-dimensional macroscopic functional materials that are not only active, but also responsive to external cues, and (2) to direct the assembly of polymeric actin and tubulin filaments into liquid crystalline phases, where the interplay between elasticity and activity can be used to manipulate the dynamics of the system. The results presented in this talk will then be used to discuss how one might design a new generation of synthetic active systems capable of performing specific, engineered functions.
Professor Christophe Coperet, ETH Zurich, Wheland Lecture
Surface Coordination Chemistry
The Tuesday JFI Seminar - Prof. Wassem Bakr, Department of Physics, Princeton University
Site-Resolved Microscopy of Ultracold Fermi-Hubbard Systems in new RegimesThe ability to probe and manipulate ultracold fermions in optical lattices at the atomic level using quantum gas microscopes has enabled quantitative studies of Fermi-Hubbard models in a temperature regime that is challenging for state-of-the-art numerical simulations. Experiments have focused on spin-balanced gases of repulsively interacting atoms with the hope of elucidating phenomena in high-temperature superconductors. In this talk, I will present experiments that explore the Hubbard model in two new regimes: repulsive gases with spin-imbalance and attractive spin-balanced gases. In the first regime, we observe canted antiferromagnetism at half-filling, with stronger correlations in the direction orthogonal to the magnetization. Away from half-filling, the polarization of the gas exhibits non-monotonic behavior with doping, resembling the behavior of the magnetic susceptibility of the cuprates. The attractive Hubbard model studied in the second set of experiments is the simplest theoretical model for studying pairing and superconductivity of fermions in a lattice. Our measurements on the normal state reveal checkerboard charge-density wave correlations close to half-filling. The charge-density-wave correlations are a sensitive thermometer in the low temperature regime relevant for future studies of inhomogeneous superfluid phases in spin-imbalanced attractive gases.For further information please contact Brenda Thomas at 773-702-7156 or by email at firstname.lastname@example.org. You may also contact the Host, Jonathan Simon at 773-702-9661 or via email to email@example.com.
Professor Christophe Coperet, ETH Zurich, Wheland Lecture
NMR Chemical Shifts: Beyond Numbers and How to Use them to Decode the Reactivity of Organometallic Compounds
Professor Christophe Coperet, ETH Zurich, Wheland Lecture
Molecular Understanding and Controlled Functionalization of Surfaces Towards Single-Site Catalysts and Beyond
blob of self-confining turbulence12:00 staging: bring lunch
12:15 execution: launch
Carlo Rubbia, Nobel Prize in Physics 1984
Nigel Goldenfeld, University of Illinois
The life and death of turbulenceHow do fluids become turbulent as their flow velocity is increased? During the last ten years, exquisite experiments, numerical simulations and pure theory have uncovered a remarkable series of connections between transitional turbulence, phase transitions and renormalization group theory, high energy hadron scattering, the statistics of extreme events, and even population biology. In this talk, I will outline how these developments and strange connections imply that a fluid at the boundary between turbulence and laminar flow behaves precisely like an ecosystem at the verge of extinction, a prediction that is supported by recent experiments.
The Tuesday JFI Seminar - Prof. Philip Kim, Department of Chemistry, Harvard University
Materials in 2-dimension and Beyond: Platform for Novel Electronics and OptoelectronicsHeterogeneous interfaces between two dissimilar materials are an essential building block for modern semiconductor devices. The 2-dimensional (2D) van der Waals (vdW) materials and their heterostructures provide a new opportunity to realize atomically sharp interfaces in the ultimate quantum limit for the electronic and optoelectronic processes. By assembling atomic layers of vdW materials, such as hexa boronitride, transition metal chalcogenide and graphene, we can construct atomically thin novel quantum structures. Unlike conventional semiconductor heterostructures, charge transport in of the devices is found to critically depend on the interlayer charge transport, electron-hole recombination process mediated by tunneling across the interface. We demonstrate the enhanced electronic optoelectronic performances in the vdW heterostructures, tuned by applying gate voltages, suggesting that these a few atom thick interfaces may provide a fundamental platform to realize novel physical phenomena. In this presentation, we will discuss several recent development of electronic and optoelectronic properties discovered in the van der Waals heterostructures, including hydrodynamic charge flows, cross-Andreev reflection across the quantum Hall edges states, and interlayer exciton formation and manipulations. For further information please contact Brenda Thomas at 773-702-7156 or by email at firstname.lastname@example.org. You may also contact the Host, Jiwoong Park at 773-834-3179 or via email at email@example.com.
Tracy M. Handel, PhD, Dept. of Pharmacology, School of Medicine, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego.
Structure, Activation & Inhibition of Chemokine Receptors
Professor Dale L. Boger, Stiegliitz Lecture
Redesign of Vancomycin for Resistant Bacteria
Dr. Cynthia J. Jenks, Argonne National Laboratory
A Quasi-Walk Along the Surfaces of Quasicrystals and Argonne InterfacesFor ages, scientists considered a crystal to be a solid with a repetitive internal structure. This notion was dismantled when quasiperiodic materials were discovered. Much has been learned about these fascinating intermetallic materials since their discovery and their subtleties are even more complex than imagined early on. In this talk, the growth, structure and stability characteristics of quasicrystalline materials will be discussed. Emphasis will be on their surfaces, known to have unusual characteristics, and of which scanning probe microscopies have produced some spectacular images and local probes of composition and structure, particularly low-energy ion scattering, show interesting findings. In addition, the talk will highlight ongoing research in the chemical sciences at Argonne National Laboratory and opportunities for collaborations.
Barbara Jacak, UC Berkeley and Lawrence Berkeley National Lab
Nuclear Physics: Then and Now
IME Distinguished Colloquium Series: Jens Norskov, Stanford University
A Molecular View of Heterogeneous CatalysisThis lecture will outline a theory of heterogeneous catalysis that allows a detailed understanding of elementary chemical processes at transition metal surfaces and singles out the most important parameters determining catalytic activity and selectivity. It will be shown how scaling relations allow the identification of descriptors of catalytic activity and how they can be used to construct activity and selectivity maps for both thermal and electro-catalytic processes. The maps can be used to define catalyst design rules and examples of their use will be given.
Manu Prakash, Stanford University
Life in flatland: Toy models and systems to explore origins of behavior in non-neuronal ensemblesDiverse multi-cellular animals encode a breathtaking diversity of natural behaviors. Non local interactions in traditional nervous systems make the study of underlying origins of behavior in animals difficult (and fascinating). It is a well known fact that simple dynamical systems can also encode perplexing complexity with purely local update rules. In this talk, using a variety of toy models and systems, we will explore how complex behavior can arise in non-neuronal ensembles; or in short "how do animals with no brains (neurons), decide, compute or think?
The Tuesday JFI Seminar - Dr. Sho Yaida, Department of Chemistry, Duke University
Novel Phase Transition within Amorphous SolidsGlassy materials are omnipresent in everyday life from windows to plastics to piles of sand. Yet our understanding of both their (equilibrium) liquid and (out-of-equilibrium) solid phases lags far behind that of crystalline counterparts. Recent advances are rapidly changing the ways in which we understand these common-yet-physically-enigmatic materials. This talk overviews one such advance -- the discovery of the Gardner phase transition from normal to marginally-stable glasses. Our work in particular indicates that such a transition, first found in abstract infinite-dimensional models, can survive down to the three-dimensional world. This transition reinforces the overriding role of rugged free-energy landscapes that dictate physics of glassy systems, with tangible consequences on jamming, yielding, and beyond.
For further information please contact Brenda Thomas at 773-702-7156 or by email at firstname.lastname@example.org. You may also contact the Host, Arvind Murugan at 773-834-3146 or via email at email@example.com.
Manu Prakash, PhD, Bioengineering, Stanford University
Life in flatland: Emergent origins of behavior in non-neuronal systemsDiverse multi-cellular animals encode a breathtaking diversity of natural behaviors. Non local interactions in traditional nervous systems make the study of underlying origins of behavior in animals difficult (and fascinating). It is a well-known fact that simple dynamical systems can also encode perplexing complexity with purely local update rules. In this talk, using a variety of toy models and systems, we will explore how complex behavior can arise in non-neuronal ensembles; or in short "how do animals with no brains (neurons), decide, compute or think?”.
Professor Bryan Dickinson, University of Chicago
Molecular Imaging and Evolutionary Approaches to Probe and Control Biology
IME Special Seminar: Antoine Georges
Quantum Materials: Bridging Physical Mechanisms, Simple Models and Realistic ComputationsQuantum Materials display competing phases with fascinating physical properties, which result from the multiple degrees of freedom in presence (charge, spin, orbital, lattice) and from strong electronic correlations. In this talk, I will show how computational methods aimed at the quantum many-body problem can be combined with realistic electronic structure methods in order to shed light on these physical properties, help identify relevant mechanisms and formulate simple effective models. This will be mostly illustrated by rare-earth nickelates, a family of materials displaying a metal-insulator transition which can be controlled by strain, gating or light, pulses.
The Tuesday JFI Seminar - Suri Vaikuntanathan, Department of Chemistry, University of Chicago
Non-equilibrium Pathways for Self Assembly and OrganizationNonequilibrium forces can drive specific and novel pathways to modulate self-assembly and organization. The close connection between energy dissipation and organization is particularly apparent in biology. Indeed, it has been demonstrated that nonequilibrium forces are crucial for the functioning of biochemical processes responsible for error correction, adaptation and timing of events in the cell cycle. However, unlike the behavior and characteristics of equilibrium systems, where no energy is dissipated, general principles governing fluctuations about a steady state or the steady state itself in far-from-equilibrium conditions are just being discovered. In my talk, I describe how tools from non-equilibrium statistical mechanics can be used to direct self assembly far-from-equilibrium, engineer novel spatiotemporal correlations in active liquids, and finally support properties such as ultra sensitivity in non-equilibrium biochemical networks. These results provide a framework for uncovering fundamental design principles of organization in non-equilibrium chemical and biological processes.
For further information please contact Brenda Thomas at 773-702-7156 or by email at firstname.lastname@example.org. You may contact the Host, Aaron Dinner at 773-702-2330 or via email to email@example.com.
Polina Anikeeva, PhD, MatSci and Eng, MIT
Probing Neural Function with Electronic, Optical & Magnetic MaterialsMammalian nervous system contains billions of neurons that exchange electrical, chemical and mechanical signals. Our ability to study this complexity is limited by the lack of technologies available for interrogating neural circuits across their diverse signaling modalities without inducing a foreign-body reaction. My talk will describe neural interface strategies pursued in my group aimed at mimicking the materials properties and transduction mechanisms of the nervous system. Specifically, I will discuss (1) Fiber-based probes for multifunctional interfaces with the brain and spinal cord circuits; (2) Magnetic nanotransducers for minimally invasive neural stimulation; and (3) Active scaffolds for neural tissue engineering and interrogation.
Fiber-drawing methods can be applied to create multifunctional polymer-based probes capable of simultaneous electrical, optical, and chemical probing of neural tissues in freely moving subjects. Similar engineering principles enable ultra-flexible miniature fiber-probes with geometries inspired by nerves, which permit simultaneous optical excitation and recording of neural activity in the spinal cord allowing for optical control of lower limb movement. Furthermore, fiber-based fabrication can be extended to design of scaffolds that direct neural growth and activity facilitating repair of damaged nerves.
Molecular mechanisms of action potential firing inspire the development of materials-based strategies for direct manipulation of ion transport across neuronal membranes. For example, hysteretic heat dissipation by magnetic nanomaterials can be used to remotely trigger activity of neurons expressing heat-sensitive ion channels. Since the alternating magnetic fields in the low radiofrequency range interact minimally with the biological tissues, the magnetic nanoparticles injected into the brain can act as transducers of wireless magnetothermal deep brain stimulation. Similarly, local hysteretic heating allows magnetic nanoparticles to disrupt protein aggregates associated with neurodegenerative disorders.
Professor Yossi Weizmann, University of Chicago
Synthetic Nucleic Acid Topology and Colloidal LEGO-Like Nanoparticles for Biological and Plasmonic Applications
Frederick A. Heberle, PhD, Biology & Soft Matter Oak Ridge National Laboratory
Lipid organization in complex biomimetic membranes: Insight from Scattering & SimulationThe 3-dimensional architecture of biological membranes has functional consequences for living cells. In the outer leaflet of the plasma membrane, lipids are thought to organize into ordered yet fluid domains, with diverse evidence supporting participation of these “rafts” in membrane processes including protein sorting and signaling. Cells also actively maintain an asymmetric distribution of different lipid types between the plasma membrane’s inner and outer leaflets, resulting in transmembrane differences in fluidity and charge density. Despite intense interest, the fundamental mechanisms controlling raft size and morphology, as well as coupling between leaflets of different composition, remain elusive. The precise determination of phase-separated and asymmetric bilayer structure is a crucial step toward a deeper understanding of these mechanisms. To this end, small-angle neutron and X-ray scattering are powerful biophysical tools for interrogating both lateral and transverse bilayer structure with sub-nanometer resolution. Molecular dynamics simulations probe further still, providing a glimpse of membrane organization with atomic detail. In this talk, I will describe new approaches for combining experimental and computational data to obtain a detailed structural picture of complex biomimetic membranes.
IME Seminar: Aaron Streets, University of California, Berkeley
Imaging and Sequencing Single CellsQuantitative cellular imaging with coherent Raman microscopy reveals morphological characteristics and chemical composition at the single-cell level. Meanwhile recent advances in high-throughput sequencing have enabled whole-transcriptome profiling of gene expression in single cells. Both measurements can uncover heterogeneity in cellular populations that would otherwise be obscured in ensemble measurement. Furthermore both imaging and gene expression profiling can be used to quantify cell state during differentiation. However, in order to infer the relationship between gene expression and morphological phenotypes, it is necessary to image and sequence the same single cell. We use a microfluidic platform to couple imaging and RNA sequencing of single cells and present recent developments on how to analyze large, multimodal, single-cell datasets.
Baruch Kanner, Hebrew University, Hadassah Medical School
Gating and Ion-Coupling by GAT-1, a GABA transporter from the Brain
Chiral waves from spinning tops: topology without long range order12:00 time to eat
12:15 time to listen and help
IME Seminar: Robert Seidel
Valence-Photoelectron and Auger-Emission Spectroscopy at the Solid-Liquid Interface
Special Seminar: Professor Yunho Lee, Department of Chemistry, KAIST
Small Molecule Activation of the Nickel Pincer Complexes
Kwang Seob Jeong, Department of Chemistry, Korea University
Magnetic Property of Colloidal Nanocrystals with Electrons in the Conduction BandThis seminar presents results on the magnetic property of the colloidal quantum dot with controlled electron doping and in the absence of any heterogeneous metal impurity, and its correlation with the optical property. Depending on the number of electrons, the magnetism can be switched from diamagnetism to paramagnetism, and vice versa. Furthermore, the intraband transition created by a cation exchange method, and the ultrafast intraband Auger process induced by multiphoton mid-IR irradiation will be discussed as well.
Simulating ricochet off of sand: Surprising behavior at low speed.Come at noon with food and conversations
Topic of the day at 12:15.
Special Seminar: Professor Alex Travesset, Iowa State University and Ames Laboratory
Geometry, Topology, and Nanoparticle Superlattice Structure
When the Hall effect throws you a curveEat: 12:00
Swerve with the curve: 12:15
Who choreographed my cell clusters?Eat: 12:00
solve mystery: 12:15
Molecular Tetris: Vapor Depositing to Enhanced Stabilitynoon: eat food
12:15 let the games begin.
IME Special Seminar: Phillip Szuromi, Senior Editor, Science
Scientific Publishing from the InsideI will give a brief overview of the mission of AAAS and the Science family of journals. I will then discuss how the review process works at Science, and how this has changed (and not changed) from the print to the internet era. Finally I will offer some thoughts on what we are looking for in a submission to help potential authors gauge the suitability of a submission.
Aaron Hoskins, PhD, Uwisc
Spliceosome Function and Structure
Molecular TherapeuticsCynthia Burrows, PhD
University of Utah
The Epigenetics of Guanine in G-Quadruplexes
Tarun Kapoor, PhD
Chemical Approaches to Dissect the Diverse Functions of Proteins in the AAA+ Superfamily
Jon Clardy, PhD
Harvard Medical School
Chemical Ecology and Molecular Therapeutics
Jason Gestwicki, PhD
University of California, San Francisco
Targeting Protein-Protein Interactions in Chaperone Networks
Nathanael Gray, PhD
Harvard Medical School
New Chemical Approaches to Drugging Oncogenic
Hening Lin, MD
Sirtuins and Novel PTMs in Cell Signaling and Cancer
Philip Cole, PhD
Johns Hopkins School of Medicine
Targeting Lysine Reversible Modifications with Designed Small Molecules
Prof. Liqiang Mai - State Key Laboratory of Advanced Technology for Materials Synthesis & Processing Wuhan University of TechnologyOne-dimensional nanomaterials can offer large surface area, facile strain relaxation upon cycling and efficient electron transport pathway to achieve high electrochemical performance. Hence, nanowires have attracted increasing interest in energy related fields. We designed the single nanowire electrochemical device for in situ probing the direct relationship between electrical transport, structure, and electrochemical properties of the single nanowire electrode to understand intrinsic reason of capacity fading. The results show that during the electrochemical reaction, conductivity of the nanowire electrode decreased, which limits the cycle life of the devices.1 We have fabricated hierarchical MnMoO4/CoMoO4 heterostructured nanowires by combining "oriented attachment" and "self-assembly".2 The asymmetric supercapacitors based on the hierarchical heterostructured nanowires show a high specific capacitance and good reversibility with a cycling efficiency of 98% after 1,000 cycles. Then, we designed the general synthesis of complex nanotubes by gradient electrospinning, including Li3V2(PO4)3, Na0.7Fe0.7Mn0.3O2 and Co3O4 mesoporous nanotubes, which exhibit ultrastable electrochemical performance when used in lithium-ion batteries, sodium-ion batteries and supercapacitors, respectively.3 In addition, we have successfully fabricated a field-tuned hydrogen evolution reaction (HER) device with an individual MoS2 nanosheet to explore the impact of field effect on catalysis.4 We also constructed a new-type carbon coated K0.7Fe0.5Mn0.5O2 interconnected nanowires through a simply electrospinning method. The interconnected nanowires exhibit a discharge capacity of 101 mAh g-1 after 60 cycles, when measured as a cathode for K-ion batteries.5 Our work presented here can inspire new thought in constructing novel one-dimensional structures and accelerate the development of energy storage applications.
Prof. Shaul Mukamel, Department of Chemistry & Department of Physics and Astronomy
Catching Conical Intersections in the Act; Ultrafast Multidimensional Spectroscopy with X-ray pulses and Quantum LightABSTRACT: Multidimensional spectroscopy uses sequences of optical pulses to study dynamical processes in complex molecules through correlation plots involving several time delay periods. Extensions of these techniques to the x-ray regime will be discussed. Ultrafast nonlinear x-ray spectroscopy is made possible by newly developed free electron laser and high harmonic generation sources. The attosecond duration of X-ray pulses and the atomic selectivity of core X-ray excitations offer a uniquely high spatial and temporal resolution. Stimulated Raman detection of an X-ray probe may be used to monitor the phase and dynamics of the nonequilibrium valence electronic state wavepackets created by e.g. photoexcitation, photoionization and Auger processes. Conical intersections (CoIn) dominate the pathways and outcomes of virtually all photophysical and photochemical molecular processes. Despite extensive experimental and theoretical effort CoIns have not been directly observed yet and the experimental evidence is being inferred from fast reaction rates and some vibrational signatures. Novel ultrafast X ray probes for these processes will be presented. Short X-ray pulses can directly detect the passage through a CoIn with the adequate temporal and spectral sensitivity. The technique is based on a coherent Raman process that employs a composite femtosecond/attosecond X-ray pulse to directly detect the electronic coherences (rather than populations) that are generated as the system passes through the CoIn. Diffraction of X- ray pulses can be used to image the transition charge densities associated with the electronic coherence.
Using the quantum nature of light in spectroscopy will be discussed. Strong coupling of molecules to the vacuum field of micro cavities can modify the potential energy surfaces thereby manipulating the photophysical and photochemical reaction pathways. The photonic vacuum state of a localized cavity mode can be strongly mixed with the molecular degrees of freedom to create hybrid field- matter states known as polaritons. Simulations of the non-adiabatic avoided crossing of sodium fluoride in a cavity which incorporate the quantized cavity field into the nuclear wave packet dynamics will be presented. Numerical results show how the branching ratio between the covalent and ionic dissociation channels can be strongly manipulated by the optical cavity. Host: Norbert Scherer, 2-7069 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Yoav Lahini, Harvard University
Non-Monotonic Aging and Memory Retention in Disordered Mechanical SystemsI will describe the observation of slow relaxations, aging and memory effects - hallmarks of glassy dynamics – in the mechanical response of two disordered systems: thin sheets crumpled into a ball and elastic foams. In particular, I’ll report the observation of a non-monotonic aging response that can last many hours. I will then describe ongoing experiments that exploit the macroscopic nature of these systems to try and uncover the underlying mechanisms. The experimental results are in good agreement with a phenomenological framework recently used to describe observations of monotonic aging in several glassy systems. This suggests not only a general mechanism, but also that the non-monotonic behavior may be generic and that a-thermal, macroscopic systems can exhibit glassy behaviors.
The Tuesday JFI Seminar - Alan Aspuru-Guzik, Department of Chemistry & Chemical Biology, Harvard University
Billions and Billions of MoleculesMany of the challenges of the twenty-first century are related to molecular processes such as the generation and storage of clean energy, water purification and desalination. These transformations require a next generation of more efficient, chemically stable, and non-toxic materials. Chemical space, the space of all possible synthesizable molecules,is practicallyinfinite and promises to have relevant candidate functional molecules to address these
challenges. One of the main goals of my research group is to develop understanding and tools for the exploration chemical space in order to accelerate the discovery of organic materials. Our design cycle is sped up by the constant interaction of theoreticians and experimentalists, the use of high-throughput computational techniques,machine learning, and the development of specialized big data tools. We have had recent successes in theoretically predicting and experimentally confirming in record times top performers in the areas of organic electronics, organic flow batteries and organic lightemitting diodes. In this talk, I will discuss what I consider are the key factors related with a successful high-performance screening approach as illustrated by these three different applications. I will end by discussing the future prospects and challenges associated with developing appropriate metrics for the cartography of chemical space. Polina Navotnaya, 2-6066 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Jaeger Fest Symposium
The World in a Grain of SandThe central theme of this symposium is the emergent collective behavior of many interacting particles and the way this behavior manifests across leng scales: from the self-assembly of nanoparticles to the formation of planets.
Jaeger Fest Symposium
MRSEC Tutorials for graduate students and postdocsThe central theme of this symposium is the emergent collective behavior of many interacting particles and the way this behavior manifests across leng scales: from the self-assembly of nanoparticles to the formation of planets.
Jacob Bean, University of ChicagoHost: Mel Shochet
IME Distinguished Colloquium Series: Daniel Loss
Spin Qubits in Semiconductors: An Overview and OutlookThis talk will provide an overview of spin qubits in semiconducting nanostructures such as quantum dots and nanowires for electron and hole spins from a theorist's point of view. Despite enormous experimental efforts in many labs worldwide over the last twenty years, progress has been slow due to many challenges posed by complex material issues and the related many-body physics limiting the coherence of spin qubits. Nevertheless, the field has evolved steadily, in theory and experiment, and there is a strong belief in the community that the ultimate goal of building a powerful quantum computer most likely will be reached with spin qubits in semiconductor material which have the advantage of being inherently small and fast: In principle, it is possible to fit a billion spin qubits on a square centimeter and have them function at a clock speed of GHz. I will mention recent development and challenges for implementing surface code structures, in particular for Si or Ge hole-spin qubits in combination with superconducting striplines. If time permits, I will mention some recent theoretical ideas on hybrid systems which aim at combining topological qubits, such as Majorana fermions and parafermions, with spin qubits.
Cary Forest, Department of Physics, University of Wisconsin
Energy Transformation between Forms in the Big Red Plasma BallAstrophysical plasma are often characterized by quasi-stationary magnetized plasmas which both pressure dominated and flow dominated, and yet still behave as ideal plasmas with fluid and magnetic Reynolds numbers being large so that magnetic fields are frozen into the flowing, often turbulent plasma. The Big Red Plasma Ball is a flexible user facility designed to study a range of astrophysically relevant plasma processes in this unique regime, and to explore novel geometries and flows that mimic astrophysical systems. A multi-cusp magnetic bucket constructed from strong samarium cobalt permanent magnets now confines a 10 m3, fully ionized, magnetic-field-free plasma in a spherical geometry. Plasma parameters of Te ~5 to 20 eV and densities of ~1011 to 5 x 1012 cm-3 provide an ideal testbed for a range of astrophysical experiments, including self-exciting dynamos, plasma accretion via the magneto-rotational instability [MRI], collisionless magnetic reconnection, jet stability, stellar winds and more. This talk will describe the unique capabilities of BRPB, along with several experiments, in both operating and planning stages, that illustrate its possibilities. References: 1. C.B. Forest et al., J. Plasma Phys. 81, 345810501 (2015). 2. C. Cooper et al., Phys. Plasmas, 21, 013505 (2015).
The Tuesday JFI Seminar - Matteo Cargnello, Chemical Engineering Department, Stanford University
Tackling Big Challenges Using Tiny CrystalsABSTRACT: The understanding that fossil fuels are not endless and that their extensive use is causing irreversible climate changes prompted us to realize that we are in urgent need of sustainable energy generation processes, energy vectors, and solutions to reduce pollution and greenhouse gas emissions. Despite replacing fossil fuels while maintaining or improving the current standards of living with a growing population is one of the biggest challenges that we have to face, the solution might lie in tiny pieces of matter: nanocrystals. Nanocrystals have been known for a long time but it is only recently that we have been able to better study and control their properties. The advent of nanotechnology and its associated tools allowed indeed to manipulate the composition, size, shape, functionalization and assembly of nanocrystals and to create nanoarchitectures and macroscopic devices with novel properties and unrivaled performance. In this talk, the use of uniform and tailored nanocrystals for energy and environmental applications will be presented, with emphasis on how to precisely control the nanostructures to understand and exploit interactions between well defined building blocks. Applications include hydrogen generation through photocatalysis, reduction of methane emissions, pollution control, and fundamental understanding of reaction mechanisms. It is expected that advancements in the preparation and use of these tiny crystals can bring immense benefit for making big challenges more approachable. Host: Dmitri Talapin, 4-2607 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Closs Lecture-Martyn Poliakoff, University of Nottingham
Andrew Ferguson, PhD, UIUC Materials Science and Engineering Department
Machine learning in soft and biological materials: Engineering self-assembling colloids and viral phase behaviorData-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 soft responsive actuators, biomimetic polyhedral encapsulants, and substrates for high-density information storage. In the first part of this talk, I will describe our applications of nonlinear manifold learning to determine low-dimensional "assembly landscapes" from computer simulations and experimental particle tracking data for self-assembling patchy colloids. These landscapes connect colloid architecture and prevailing conditions with emergent assembly behavior, informing how to engineer the stability and accessibility of desired aggregates. Empirical models of viral fitness present a means to rationally design antiviral therapeutics by revealing vulnerabilities within the viral proteome. In the second part of this talk, I will discuss the translation of clinical sequence databases into spin glass models of viral fitness that reveal an interesting connection with statistical thermodynamics in which a data-driven fitness model of HIV admits an "error catastrophe" – mutational meltdown of the viral quasispecies induced by an elevated mutation rate – isomorphic to a first order phase transition. Our work informs new antiviral control strategies and provides a rationale for why HIV can live on the precipice of the error catastrophe with impunity.
Erez Berg, University of ChicagoHost: Philippe Guyot-Sionnest
Sophie Martin, PhD, University of Lausanne
How to mate once and only once: Yeast gamete fusion rapidly reconstitutes a bi-partite transcription factor to block re-fertilization
Stuart Rowan, The University of Chicago
Using Dynamic Chemistry to Access Stimuli-Responsive and Adaptive MaterialsThe dynamic bond can be defined as any class of bond that selectively undergoes reversible breaking and reformation, usually under equilibrium conditions. The incorporation of dynamic bonds (which can be either covalent or non-covalent) allows access to structurally dynamic polymers. Such polymers can exhibit macroscopic responses upon exposure to an environmental stimulus, on account of a rearrangement of the polymeric architecture. In such systems, the nature of the dynamic bond not only dictates which stimulus the material will be responsive to but also plays a role in the response itself. Thus, such a design concept represents a molecular level approach to the development of new stimuli-responsive materials. We have been interested in the potential of such systems to access new material platforms and have developed a range of new mechanically stable, structurally dynamic polymer films that change their properties in response to a given stimulus, such as temperature, light or specific chemicals. Such adaptive materials have been targeted toward applications that include healable plastics, responsive liquid crystalline polymers, chemical sensors, thermally responsive hydrogels, shape memory materials and mechanically dynamic biomedical implants. Our latest results in this area will be discussed.
The Tuesday JFI Seminar - Mohammad Hafezi, Joint Quantum Institute, University of Maryland
Topological Photonics: From Classical to QuantumThere are tremendous efforts underway to better understand systems with topological features --- global properties that are not discernible locally. The best-known examples are quantum Hall effects in electronic systems, where insensitivity to local properties manifests itself as conductance through edge states that are insensitive to defects and disorder. In this talk, I demonstrate how similar physics can be observed for photons; specifically, how various quantum Hall Hamiltonians can be simulated in an optical platform. I review the observation of topological photonic edge states using silicon-on-insulator technology, measurement of the associated topological invariants and our recent advances in studying the quantum transport of such structures. Furthermore, the addition of optical nonlinearity to this system provides a platform to implement fractional quantum Hall states of photons and anyonic states that have not yet been observed. More generally, the application of these ideas can lead to the development of optical devices with topological protection for classical and quantum information processing.
Stephen J. Lippard: Massachusetts Institute of Technology
Understanding and Improving Platinum Anticancer Drugs
Dmitri Feldman, Brown University
Particle-hole symmetry without particle-hole symmetry in the quantum Hall effect at ν = 5/2Numerical results suggest that the quantum Hall effect at the filling factor 5/2 is described by the Pfaffian or anti-Pfaffian state in the absence of disorder and Landau level mixing. Those states are incompatible with the observed transport properties of GaAs heterostructures, where disorder and Landau level mixing are strong. We show that the recent proposal of a PH-Pfaffian topological order by D. T. Son is consistent with all experiments. The absence of the particle-hole symmetry at the filling factor 5/2 is not an obstacle to the existence of the PH-Pfaffian order since the order is robust to symmetry breaking
Anthony Hyman, PhD, MPI Molecular Cell Biology and Genetics, Dresden
Biomolecular condensates: Organizers of cellular biochemistry
Danna Freedman:Northwestern University
Applying Inorganic Chemistry to Challenges in Physics
the faster you run, the less you rememberEat 12:00 noon
Joe Incandela, University of California,Santa Barbara/CERN
Zachariasen Lecture: "From the Higgs to dark matter: the search for the underlying code of our universe"
Lee Lecture: Professor Matthew Rosseinsky, University of Liverpool
Beyond the unit cell: control of function by local structure and dynamics from fuel cell electrodes to metal-organic frameworks
Luca Delacretaz, Stanford University
Transport with translational order and bad metalsI will present a hydrodynamic theory of weakly disordered electronic systems with fluctuating or static translational order, such as charge/spin density waves or Wigner crystals. This hydrodynamic approach leads to universal expressions for low frequency ac conductivities and viscosities. I will argue that similar ac conductivities are observed experimentally in a variety of bad metals, and conjecture that such materials have short range fluctuating charge order.
Jeremy England, MIT
Emergent Fine-tuning to Environment in a Complex Chemical reactionThe equilibrium steady state of an undriven mixture of reacting chemical species is uniquely determined by the free energy. Once external environmental drives are introduced, however, steady-state concentrations may deviate from these equilibrium values via sustained absorption and dissipation of work. From a physical standpoint, the living cell is a particularly intriguing example of such a nonequilibrium system, because the environmental work sources that power it are relatively difficult to access – only the proper orchestration of many distinct catalytic actors leads to a collective behavior that is competent to harvest and exploit available metabolites. Here, we study the dynamics of an in silico chemical network with random connectivity in a driven environment that only makes strong chemical forcing available to rare combinations of concentrations of different molecular species. We find that the long-time dynamics of such systems biased towards the spontaneous extremization of forcing, so that the molecular composition converges on states that exhibit exquisite fine-tuning to available work sources.
Lee Lecture: Prof. Matthew Rosseinsky, University of Liverpool
Design of Advanced Materials?
Lukasz Fidkowski, Stony Brook University
Chiral phases in Floquet quantum systems
Alex Miller: University of North Carolina at Chapel Hill
Cation-Responsive Pincer-Crown Ether Complexes for Tunable Catalysis
1st Annual UChicago MRSEC SymposiumLearn about ongoing work in the Materials Research Center!
Explore new collaborations & research directions!
GCIS 3rd Floor Atrium
11:30am -1:30pm: Lunch and Poster Session
1:30pm - 3:00pm: IRG 1 – Dynamics of Soft Interfaces
& IRG 2 – Active Materials
3:00pm - 3:15pm: Coffee Break
3:15pm-4:45pm: IRG 3 – Engineering Quantum Materials & Seed Research – “Multifunctional Interfaces of Different Dimensionality” & “Multifunctional Porous Materials”
4:45pm: Wine and Cheese
Lisa Manning, Syracuse University
Jamming in biological tissuesHost: Sid Nagel
Philip Nelson, University of Pennsylvania
Old and new news about single-photon sensitivity in human visionOne often hears that human vision is “sensitive to single photons,” when in fact the faintest flash of light that can reliably be reported by human subjects is closer to 100 photons. Nevertheless, there is a sense in which the familiar claim is true. Experiments conducted long after the seminal work of Hecht, Shlaer, and Pirenne now allow a more precise, and in some ways even more remarkable, conclusion to be drawn about our visual apparatus. A simple model that incorporates both old news (response of single rod cells) and newer news (loss at the first synapse) can account in detail for both old and new psychophysical data.
The 2nd Tuesday JFI Colloquium - Eric Borguet - Department of Chemistry, Temple UniversityInterfacial water structure, which can be probed by vibrational sum-frequency generation (vSFG) spectroscopy, is key to many processes. Time-resolved vSFG shows that in the absence of surface charge (pH 2), water at silica surfaces exhibits significantly slower OH stretch vibrational relaxation (~600 fs) compared to bulk water. However, at charged silica surfaces (e.g., pH 6), bulk-like fast dynamics (~200 fs) are observed at low ionic strength. This decelerates to ~600 fs, with the addition of NaCl. In parallel, vSFG results demonstrated that silica interfacial water structure is most sensitive to cations at pH=6-8. Consequently, it is unclear whether the observed slowing of the vibrational dynamics is due to the reduction in Debye length, or because of changes in the local hydrogen bonding environment caused by the electrolyte and how this might depend on the identity of the ions. Additional spectroscopic and time-resolved vSFG experiments on aqueous Al2O3 interfaces shed light on the ongoing debate on the role of ions in interfacial water structure and whether the observed behavior is specific to silica/water interfaces or can be generalized to other systems. Philippe Guyot-Sionnest, 2-7461 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Snir Gazit, University of California at Berkeley
Charged fermions coupled to Ising gauge fields: Symmetry breaking, confinement, and emergent Dirac fermions.Lattice gauge theories are ubiquitous in physics, describing a wide range of phenomena from quark confinement to quantum materials. At finite fermion density, gauge theories are notoriously hard to analyze due to the fermion sign problem. Here, we investigate the Ising gauge theory in 2+1 dimensions, a problem of great interest in condensed matter, and show that it is free of the sign problem at arbitrary fermion density. At generic filling, we find that gauge fluctuations mediate pairing leading to a transition between a deconfined BCS state to a confined BEC. At half-filling, a π-flux phase is generated spontaneously with emergent Dirac fermions. The deconfined Dirac phase, with a vanishing Fermi surface volume, is a non-trivial example of violation of Luttinger's theorem due to fractionalization. At strong coupling, we find a single continuous transition between the deconfined Dirac phase and the confined BEC, in contrast to the expected split transition.
Kharasch Memorial Lecture - Sir Shankar Balasubramanian, University of Cambridge
How large is the natural DNA alphabet?
Peter Littlewood, University of Chicago
Physics of SustainabilityHost: Mel Shochet
Daniel Scolnic, University of Chicago
Measuring the size of the Universe with Standard CandleAstrophysicists use standard candles, objects which have roughly the same luminosity, to infer distances to far-away parts of the universe. Standard candles of variable stars called ‘cepheids’ were used to discover the expanding universe, and standard candles of exploding stars called ‘supernovae’ were used to discover the accelerating universe. Together, these two standard candles can be used to measure the size of the universe. Interestingly, this measurement of the size of the universe recovered conflicts with measurements of the size of the universe from extrapolations of data from the Cosmic Microwave Background. I will go over how we make our measurement, from soup to nuts, and discuss how we can be confident in the accuracy of our values. I will then discuss different ways too explain the tension we see in the different sets of measurements, and possible new physics that may be on the horizon.
The 1st Tuesday JFI Colloquium - Benjamin Lev, Department of Physics and Applied Physics - Stanford University
New Tools for Exploring Nonequilibrium Quantum Many-Body PhysicsABSTRACT: The simulation of quantum systems using ultracold atomic gases—quantum simulation—may be viewed as the creation of novel quantum systems in their own right rather than the simulation of well-known models. Often these systems possess collective properties impossible to observe in the solid state. In particular, these gaseous systems provide unique testbeds for emergent physics, especially that out of equilibrium. We present two novel avenues of inquiry into quantum nonequilibrium physics: the creation of dissipative quantum spin glasses and quantum neural networks using atoms coupled to the photonic modes of a confocal optical resonator and the study of nonequilibrium quench dynamics in highly magnetic and strongly interacting gases. Besides investigating long-unresolved issues in statistical mechanics (i.e., the order of spin glasses and thermalization in closed quantum systems), the experimental directions discussed point to novel neuromorphic computational architectures relying on driven-dissipative quantum dynamics.Host: Jonathan Simon, 2-9661 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Kharasch Memorial Lecture - Sir Shankar Balasubramanian, University of Cambridge
Decoding human genomes on a population scale
Dominic Else, University of California, Santa Barbara
Floquet Time Crystals: How time-translation symmetry protects phases of matterA "Floquet time crystal" is a phase of matter in a periodically driven (Floquet) system which spontaneously breaks discrete time-translation symmetry. They are an entirely new "non-thermal" phase of matter which cannot exist in undriven systems. In this talk, I will discuss the recent theoretical prediction and experimental observation of Floquet time crystals. Time-translation symmetry occupies a special role in physics, since its generator is the Hamiltonian itself. Nevertheless, the theoretical formulation of time crystals turns out to be *almost* the same as for other symmetry-breaking phases of matter. I will also consider phases of matter in which the discrete time-translation symmetry is not spontaneously broken but nevertheless protects non-trivial phases, which are the analogs of "symmetry-protected topological" and "symmetry-enriched topological" phases for other symmetries.
Jingyuan Chen, Stanford University
Exact Bose-Fermi Duality on 3D Euclidean LatticeRecently a conjectured Bose-Fermi duality in 3 spacetime dimensions has drawn much interest from both high energy and condensed matter communities. We prove this duality by constructing an exact duality on lattice and showing our exact duality reduces to the conjectured duality in the continuum limit. All steps are analytic, exact, and simple.
Qiu Wang, Duke University
Leveraging Chemistry for Biology and Therapy: – New amination strategies to access biologically important molecules
Cameron Reed, Alma College
The Manhattan Project: A Look at the Physics"Host: Henry Frisch
Andrew Kruse, PhD, Harvard Medical School
New approaches to investigate G protein-coupled receptor function
Lenka Zdeborova, CNRS & CEA, Saclay, France
Statistical physics approach to compressed sensing and generalized linear regressionBayesian inference and statistical physics are formally closely related. Therefore methodology and concepts developed in statistical physics to understand disordered materials such as glasses and spin glasses can be elevated to analyze models of in statistical inference. We will present this approach in a rather general setting that covers analysis of compressed sensing, generalized linear regression, and the perceptron - a kind of a single layer neural network. At the one hand, this approach leads to the approximate message passing algorithm that is gaining its place among other widely used regression and classification algorithms. At the other hand, the related analyses leads to identification of phase transitions in the performance of Bayes-optimal estimators. We will discuss relation between these phase transitions and algorithmic hardness, and in the case of compressed sensing we will show how this understanding leads to a design of optimal measurement protocols.
Based partly on "Statistical-physics-based reconstruction in compressed sensing" PRX 2012 and reviewed in "Statistical physics of inference: Thresholds and algorithms" Advances of Physics 2016.
Andy Borovik:University of California, Irvine
Synthetic Chemistry as a Window into Biology
JFI Seminar - Prof. David Cobden, Department of Physics, Washington University
"Electronic Phases and Phase Transitions in Van der Waals Monolayers"ABSTRACT: Atomically thin materials can host many kinds of electronic phases, some unique to the 2D limit. Our observations indicate the realization of a quantum spin Hall state, an excitonic insulator, superconductivity, and ferro- and antiferromagnetism in van der Waals monolayers. Unlike 3D solids, monolayers are amenable to surface probes and can be doped by electrostatic gating. We are thus investigating ways to induce transitions between these phases electrostatically. In WTe2 monolayers at low temperatures we observe a transition between a two-dimensional topological insulator and a bulk conducting phase as a function of gate voltage, representing a gate-controlled quantum phase transition.Host: Jiwoong Park, 4-3179 or via email to firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Cenke Xu, University of California, Santa Barbar
self-dual quantum critical points in 2+1 dimensions
Jennifer M. Heemstra: University of Utah
Harnessing Nucleic Acid Molecular Recognition and Self-Assembly for Biosensing and Biomolecular Imaging
Two dynamical interfaces walk into an IRG…
a recap of tuesday's idea session12:00 Eat real food
12:15 digest bloblets
Zoran Hadzibabic, University of Cambridge
Quantum gas in a boxHost: Cheng Chin
Anette Hosoi, MIT
Hydrodynamics of Hairy SurfacesFlexible slender structures in flow are everywhere. While a great deal is known about individual flexible fibers interacting with fluids, considerably less work has been done on fiber ensembles, such as fur or hair, in flow. These hairy surfaces are abundant in nature and perform multiple functions from thermal regulation to water harvesting to sensing. Motivated by these biological systems, we consider two examples of hairy surfaces interacting with flow: (1) air entrainment in the fur of diving mammals and (2) symmetry breaking in hairy micro-channels.
In the first example, we take inspiration from semi-aquatic mammals (such as fur seals, otters, and beavers) which have specially adapted fur that serves as an effective insulator both above and below water. Many of these animals have evolved pelts that naturally entrap air when they dive. This air: (1) provides additional insulation under water, (2) provides added buoyancy, and (3) facilitates water shedding when the animals resurface. In this study we investigate diving conditions and fur properties which amplify air entrainment in fur. In the second example, we consider a fundamental component in hydraulic systems, the flow rectifier. One of the simplest ways to generate asymmetry in these devices is with a ball valve in which flow is completely obstructed in one direction and free to flow in the other. In this work we seek a variation that: (1) allows the designer to modulate the relative resistances in the rectifier and (2) can be achieved with solid state components (i.e. no moving parts).
The Tuesday JFI Seminar - Monika Schleier-Smith, Department of Physics, Stanford University
"Echoes of Entanglement: from Quantum Metrology to Scrambling"ABSTRACT: In the quest to approach the fundamental Heisenberg Limit in precision measurements, central challenges are the generation and detection of highly entangled states. I will describe how both of these challenges can be mitigated by “echo spectroscopy,” a technique inspired by the Loschmidt echo, a paradigmatic probe of chaos. A key ingredient is to effectively reverse the flow of time in an interacting many-body system by switching the sign of the Hamiltonian. I will describe progress towards engineering spin models with non-local, switchable-sign interactions using cold atoms strongly coupled to light an optical cavity. Intriguingly, similar non-local interactions feature in models for understanding fundamental bounds on chaos and information scrambling derived from the study of black holes, opening prospects for investigating these bounds in the laboratory.Host: Jonathan Simon, 2-9661 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Viviana Gradinaru, PhD, CALTECH
Optogenetic, tissue clearing, and viral vector approaches to understand and influence whole-animal physiology and behaviorWe develop & employ optogenetics, tissue clearing and viral vectors to gain new insights on circuits underlying locomotion, reward & sleep. I will discuss how bidirectional manipulation of mesopontine cholinergic cell bodies exerted opposing effects on locomotor behavior & reinforcement learning & how these effects were separable via limiting photostimulation to PPN cholinergic terminals in the ventral substantia nigra pars compacta or to the ventral tegmental area, respectively (Xiao et al, Neuron, '16). Genetically encoded tools that can be used to visualize, monitor, and modulate mammalian neurons are revolutionizing neuroscience. However, use of genetic tools in non-transgenic animals is often hindered by the lack of vectors capable of safe, efficient & specific delivery to the desired cellular targets. To begin to address these challenges, we have developed an in vivo Cre-based selection platform (CREATE) for identifying adeno-associated viruses (AAVs) that more efficiently transduce genetically defined cell populations (Deverman et al, Nature Biotechnology, '16). As a first test of the CREATE platform, we selected for viruses that transduced the brain after intravascular delivery and found a novel vector, AAV-PHP.B, that transduces most neuronal types and glia across the brain. We also demonstrate how whole-body tissue clearing can facilitate transduction maps of systemically delivered genes (Yang et al, Cell, '14; Treweek et al, Nature Protocols, '16) and how non-invasive delivery vectors can be used to achieve dense to sparse labeling to enable morphology tracing (unpublished). Since CNS disorders are notoriously challenging due to the restrictive nature of the blood brain barrier, the recombinant vectors engineered to overcome this barrier can enable potential future use of exciting advances in gene editing via the CRISPR-Cas, RNA interference and gene replacement strategies to restore diseased CNS circuits. In addition to control of neuronal activity we need feedback on how exactly the tissue is responding to modulation. We have worked on two related topics: optical voltage sensors and imaging of single molecule RNA in cleared tissue. We used directed evolution of opsins to make them better at reporting action potentials (Flytzanis et al, Nature Communications, '14). Changes in RNA transcripts can also report on activity history of brain circuits. Preserving spatial relationships while accessing the transcriptome of selected cells is a crucial feature for advancing many biological areas, from dev bio to neuroscience. We recently reported on methods for multi-color, multi-RNA, imaging in deep tissues. By using single-molecule hybridization chain reaction (smHCR), PACT tissue hydrogel embedding and clearing and light-sheet microscopy we detected single-molecule mRNAs in ~mm-thick brain tissue samples (Shah et al, Development, '16) and by rRNA labeling we mapped the identity & growth rate of pathogens in clinical samples (DePas et al,'16).
Closs Lecture-Professor Mostafa El-Sayed, Georgia Institute of Technology
Photothermal Therapy of Cancer in Cells and in Different Animals Using Gold Nano-Rods: A Progress Report
Roger Melko, Perimeter Institute
Machine Learning the Many-Body ProblemCondensed matter physics is the study of the collective behavior of infinitely complex assemblies of electrons, nuclei, magnetic moments, atoms or qubits. This complexity is reminiscent of the “curse of dimensionality” commonly encountered in machine learning. Despite this curse, the machine learning community has developed techniques with remarkable abilities to classify, characterize and interpret complex sets of data, such as images and natural language recordings. Here, we show that modern architectures for supervised learning, such as fully-connected and convolutional neural networks, can identify phases and phase transitions in a variety of condensed matter Hamiltonians. Readily programmable through open-source software libraries, neural networks can be trained to detect multiple types of order parameter, as well as highly non-trivial states with no conventional order, directly from raw state configurations sampled with standard Monte Carlo. Further, Monte Carlo configurations can be used to train a stochastic variant of a neural network, called a Restricted Boltzmann Machine (RBM), for use in unsupervised learning applications. We show how RBMs, once trained, can be sampled much like a physical Hamiltonian to produce configurations useful for estimating physical observables. Finally, we explore the representational power of quantum and classical RBMs, their role in deep learning, and its possible relationship to the renormalization group.
John Jewett: University of Arizona
Viral muses to inspire chemistry
Bloblets in your cells: what is their mission?12:00 Eat real food
12:15 digest bloblets
Steve Kivelson, Stanford University
Intertwined Order in Highly Correlated Electron FluidsHost: Paul Wiegmann
Minjung Ryu, PhD, Purdue
Language, Culture, and Learning: Implications for Interdisciplinary Research
Jonathan Simon, University of Chicago
Exploring Landau Levels in Curved SpaceI will present recent work realizing topological phases of photons, both in curved space, and in lattices. The talk will focus on our recent exploration of Landau levels on a conical surface, generated using a non-planar (twisted) optical resonator to induce a synthetic magnetic field for optical photons, and employed to validate the famous Wen-Zee action. I will then discuss recent results demonstrating strong photon-photon interactions mediated by resonator Rydberg-electromagnetically induced transparency (EIT), and techniques we are developing to assemble topological few-body states both photon-by-photon, and through microscopic devices engineered for photon thermalization. I will conclude with our recent observation of time-resolved helical edge dynamics in Z_2 topological circuit lattices, and a T-broken extension in the microwave domain using arrays of 3D cavities and circuit quantum electrodynamics techniques. This work showcases the unique possibilities for Hamiltonian engineering and control in the photonic sector, a provides a taste of upcoming breakthroughs in engineering quantum materials from photons.
The Tuesday JFI Seminar - Elisabeth Guazzelli, Aix Marseille Univ, CNRS, IUSTI, Marseille, France
Rheology of Dense Suspensions of Non-Colloidal ParticlesABSTRACT: Dense suspensions are materials with broad applications both in industrial processes (e.g. waste disposal, concrete, drilling muds, metalworking chip transport, and food processing) and in natural phenomena (e.g. flows of slurries, debris, and lava). Despite its long research history and its practical relevance, the mechanics of dense suspensions remain poorly understood. The major difficulty is that the grains interact both by hydrodynamic interactions through the liquid and by mechanical contact. These systems thus belong to an intermediate regime between pure suspensions and granular flows. We show that we can unify suspension and granular rheology under a common framework by transferring the frictional approach of dry granular media to wet suspensions of spherical particles. We also discuss non-Newtonian behavior such as normal-stress differences and shear-induced migration. Beyond the classical problem of dense suspension of hard spheres which is far from being completely resolved, there are also entirely novel avenues of study concerning more complex mixtures of particles and fluids such as those involving other types of particles (e.g. fibers) or non-Newtonian fluids (e.g. yield-stress fluids) that we will also address. Host: Heinrich Jaeger, 2-6074 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance contact Brenda Thomas at 2-7156 or by email at email@example.com.
Matthew Lapa, UIUC
Electromagnetic response and anomalies in bosonic symmetry-protected topological phasesSymmetry-protected topological (SPT) phases, gapped phases of matter protected by the symmetry of a group G and possessing interesting boundary states, have been the focus of intense investigation for the past several years. While much is known about the classification and properties of these phases, especially in low dimensions, it is still a challenge to understand the physical properties which characterize a given (interacting) SPT phase in a general dimension. In this talk I will explain how a field-theoretic description of bosonic SPT phases in terms of nonlinear sigma models (NLSMs) can be combined with the theory of gauged Wess-Zumino actions to study the electromagnetic response and anomalies of some bosonic SPT phases with U(1) symmetry in all dimensions. In particular, I will present a calculation of the topological part of the electromagnetic response of bosonic integer quantum Hall (BIQH) states in odd spacetime dimensions and bosonic topological insulator (BTI) states in even spacetime dimensions. In addition, I will argue that the boundary of the BTI state exhibits a global anomaly similar to the parity anomaly of Dirac fermions in odd spacetime dimensions. This argument can be made precise for the boundary theory of the BTI state in two spacetime dimensions. If time allows, I will explain how the connection between gauged Wess-Zumino actions and equivariant cohomology can be used to prove that these results are robust against smooth, symmetry-preserving deformations of the target space of the NLSM used to describe these states.
Gregory T. Tietjen, PhD, Yale
A biophysical approach to engineering vascular targeted nanomedicine
Ribhu Kaul, University of Kentucky
Quantum phase transitions in square lattice SU(N) and SO(N) magnetsI will discuss the phases and phase transitions in some simple SU(N) and SO(N) quantum spin models, studied both using ideas from quantum field theory and with large scale numerical simulations.
James Morken, Boston College
New Strategies in Organic Synthesis Enabled by Catalytic Reactions of Organoboron Reagents
The 1st Tuesday JFI Colloquium - Mark G. Raizen - Department of Physics, University of Texas at Austin
From Maxwell’s Demon to Einstein’s Speed DemonABSTRACT: In this talk, I will describe two historical thought experiments in statistical mechanics and their experimental realization. Maxwell’s Demon was proposed by James Clerk Maxwell in 1871 as a way to reduce the entropy of gas-phase particles by means of an “intelligent creature with deft hands.” We have realized this thought experiment with a self-acting one-way wall for atoms, as originally suggested by Maxwell. This construction has been used to cool atoms, and for efficient isotope separation which will have important medical applications. In 1907, Albert Einstein predicted that Brownian motion should be ballistic on very short time scales, rather than diffusive. Einstein concluded that this instantaneous velocity would be impossible to measure in practice, a prediction that held for over 100 years. We have realized such a ‘speed demon’ by measuring the motion of micrometer beads held in optical tweezers, and have resolved the instantaneous velocity of a Brownian particle in air and in liquid. This system can be used to study the onset of irreversibility, the “arrow of time.”Host(s):Cheng Chin, 2-7192 or via email to firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Wolfgang Ketterle, MIT
New forms of matter with ultracold atoms: synthetic gauge fields and supersolidityHosts: Cheng Chin
Yimon Aye, Cornell
Stay On Target: Deconvoluting Mixed Redox Messages through Precision Redox Targeting
The Tuesday JFI Seminar - James F. Cahoon, Department of Chemistry, University of North Carolina - Chapel Hill
From Nanowires to Nanoplatelets: Designing Semiconductor Morphology so Form Follows FunctionSemiconductors are used in a vast array of modern technologies, including solar cells that convert sunlight into electricity and microprocessors that drive computers. They can be used to direct the flow of energy in devices or to convert energy from one form to another. These functions are enabled by the specific choice of material and composition. Shape, however, is another fundamental characteristic that can be used to encode functionality. Here, I will describe my group’s efforts to usenanometer-scale morphology as a strategy to encode novel photovoltaic, electronic, and optical properties in materials created by bottom-up methods. We chemically synthesize nanostructures, such as metal oxide particles and group IV nanowires, with precise morphology and composition, and we evaluate their physical properties using nanofabrication, spectroscopic, electrochemical, and computational methods. For instance, I will describe a strategy to create silicon nanowires with lithographic-like patterns, enabling applications ranging from photonic crystals to non-volatile memory. In addition, I will outline our efforts to design wide-bandgap photocathode materials for integration in solar fuels devices. The results yield insights into the synthesis, structure-function relationships, and technological applications of designed, bottom-up semiconductor nanomaterials. Host: Bozhi Tian; Contact him at 2-8749 or via email at firstname.lastname@example.org. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at email@example.com.
Wheland Lecture - John P. Maier: University of Basel
Electronic Spectroscopy of C60+ and its Identification in Interstellar Space
The 2nd Tuesday JFI Colloquium - Hui Zhai, Tsinghua University, Institute for Advanced Study
Closs Lecture - Christopher Chang, University of California, Berkeley
Transition Metal Signaling in the Brain and Beyond
Moh El-Naggar, PhD, Depts of Physics and Astronomy, of Biological Sciences, and of Chemistry, University of Southern California
Far, Fast, & Surprising: Extracellular Electron Transport in Microbial Redox ChainsThe stepwise movement of electrons within and between molecules dictates all biological energy conversion strategies, including respiration and photosynthesis. With such a universal role across all domains of life, the fundamentals of ET and its precise impact on bioenergetics have received considerable attention, and the broad mechanisms allowing ET over small length scales in biomolecules are now well appreciated.
In what has become an established pattern, however, our planet’s oldest and most versatile organisms are now challenging our current state of knowledge. With the discovery of bacterial nanowires and multicellular bacterial cables, the length scales of microbial ET observations have jumped by 7 orders of magnitude, from nanometers to centimeters, during the last decade alone! This talk will take stock of where we are and where we are heading as we come to grips with the basic mechanisms and immense implications of microbial long-distance electron transport. We will focus on the biophysical and structural basis of long-distance, fast, extracellular electron transport by metal-reducing bacteria. These remarkable organisms have evolved direct charge transfer mechanisms to solid surfaces outside the cells, allowing them to use abundant minerals as electron acceptors for respiration, instead of oxygen or other soluble oxidants that would normally diffuse inside cells. From an environmental perspective, these microbes are major players in global elemental cycles. From a technological perspective, microbial extracellular electron transport is heavily pursued for interfacing redox reactions to electrodes in multiple renewable energy technologies.
But how can an organism transfer electrons to a surface many cell lengths away? What molecules mediate this transport? And, from a physics standpoint, what are the relevant length, time, and energy scales? We will describe new experimental and computational approaches that revealed how bacteria organize heme networks on outer cell membranes, and along the quasi-one-dimensional filaments known as bacterial nanowires, to facilitate long-range charge transport. Using correlated electron cryo-tomography and in vivo fluorescent microscopy, we are gaining new insight into the localization patterns of multiheme cytochromes along nanowires as well as the morphology and the formation mechanism of these structures. In addition, we will examine the fundamental limits of extracellular electron transport, down to microbial energy acquisition by single cells. These findings are shedding light on one of the earliest forms of respiration on Earth while unraveling surprising biotic-abiotic interactions.