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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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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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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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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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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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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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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Alex Levine, UCLA

Exploring soft low-dimensional structures in the cell: Fluctuations, mechanics, and geometry

Biology provides us with a number of effectively one- and two-dimensional elastic structures. The cytoskeleton of cells abounds with long, stiff protein filaments organized into bundles and networks. Cells are bound by and contain a wide variety of membranes, some of which have complex geometries. These lower dimensional structures are sufficiently soft to be strongly fluctuating at ambient temperature. In addition, evolution has engineered a plethora of cross-linking proteins and molecular motors that interact with these structures.

In this talk, I discuss a few examples of the role of fluctuations in soft low-dimensional biological structures, introducing the fluctuation-induced (Casimir) interaction between linkers in filament bundles. The Casimir interaction drives a new type of first-order filament bundling transition, leading to a disordered “line glass” network. I report on the collective mechanics of such filament networks. Finally, within a single bundle, I show that quenched-in braids introduce kinks (localized bends) in the time-averaged contour of the bundle, and explore how such kinks anneal over time.
Computations in Science

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

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Jessie Shelton, UIUC


Physics Colloquium

January 30, 2020
KPTC 106 | Thursday, 3:30 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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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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Tobin Marks, Northwestern University


Chemistry

February 3, 2020
Kent 120 | Monday, 3:45 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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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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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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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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Eric Kool, Stanford University


Chemistry

February 10, 2020
Kent 120 | Monday, 3:45 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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Jeremy England, GSK AI


Computations in Science

February 12, 2020
KPTC 206 | Wednesday, 12:15 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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William Lanouette, Atomic Heritage Expert and Author


Physics Colloquium

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

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Vladimir Narovlansky, Princeton University


Kadanoff Seminar

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

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Alex Spokoyny UCLA


Chemistry

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

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Hill Harman, University of California - Riverside


Chemistry

February 21, 2020
Kent 120 | Friday, 1:45 pm

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Andy Lucas, Stanford University

Mathematics of operator growth in quantum many-body systems

The Lieb-Robinson theorem is a classic result in mathematical physics which proves that in a quantum system with local interactions, the commutators of local operators essentially vanish outside of a “light cone” with an emergent, finite velocity. This result has numerous applications, from bounding classical simulatability of quantum systems to constraining entanglement growth, and many-body operator growth and chaos. In this talk, I will present new frameworks for understanding operator growth and chaos in quantum many-body systems, both with local and without local interactions, which provide qualitative improvements over existing techniques. Using these techniques, I will prove two previously open problems: (1) in spin chains with interactions that fall off with distance faster than 1/r^3, commutators of local operators can be made arbitrarily small outside of a “linear light cone” which grows at a finite velocity, just as in local systems; (2) the scrambling time for an operator to grow large in the Sachdev-Ye-Kitaev model of N fermions grows no slower than log N, when N is large but finite. These non-perturbative bounds on the many-body Lyapunov exponent are within a factor of 2 of previously calculated exponents in perturbation theory in 1/N.
Kadanoff Seminar

February 24, 2020
MCP 201 | Monday, 1:30 pm

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Sarah Reisman, California Institute of Technology


Chemistry

February 24, 2020
Kent 120 | Monday, 3:45 pm

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Dominika Zgid, Department of Chemistry, University of Michigan


The Tuesday JFI Seminar

February 25, 2020
GCIS W301 | Tuesday, 3:45 pm

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Denis Bartolo, ENS Lyon


Computations in Science

February 26, 2020
KPTC 206 | Wednesday, 12:15 pm

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Eric Sharpe, Virginia Tech


Kadanoff Seminar

February 26, 2020
MCP 201 | Wednesday, 1:30 pm

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Vladimir Rosenhaus, IAS


Kadanoff Seminar

March 2, 2020
MCP 201 | Monday, 1:30 pm

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Moungi Bawendi, Massachusetts Institute of Technology


Chemistry

March 2, 2020
Kent 120 | Monday, 3:45 pm

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Redefining the landscape - Women in STEM

Redefining the landscape - Women in STEM is an upcoming PSD & PME exhibit and speaker series featuring narratives and images of the women who are shaping STEM.
Molecular Engineering

March 5, 2020
ERC Atrium | Thursday, 4:00 pm

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Allison Narayan, University of Michigan


Chemistry

March 6, 2020
Kent 120 | Friday, 1:45 pm

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Jordan Cotler - Stanford University


Kadanoff Seminar

March 9, 2020
MCP 201 | Monday, 1:30 pm

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Chen Yang, Boston University


Chemistry

March 9, 2020
Kent 120 | Monday, 3:45 pm

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Qian Chen, Department of Chemistry, University of Illinois at Urbana-Champaign

“Cinematography” at the Nanoscale, from Colloidal Crystallization to Protein Transformation

I will discuss my group’s recent progress on applying low-dose liquid-phase TEM to synthetic and biological systems. In the first system, we directly image the otherwise elusive crystallization pathways of nanosized colloids into superlattices, where the discreteness and multi-scale coupling effects complicate the free energy landscape and the application forms of the final superlattices. We find that there exist similarities to the prevalent model system of micron-sized colloids, such as a non-classical two-step crystallization pathway, and an agreement with the capillary wave theory. But there are also differences, in particular, a universal layer-by-layer growth mode that we observe consistently for diverse nanoparticle shapes. Single particle tracking, trajectory analysis, and simulations combined unravel the energetic and kinetic features rendering this crystal growth mode possible and universal at the unexplored nanoscale, enabling advanced crystal engineering. In the second system, we sandwich and capture moving membrane proteins in their native lipid and liquid environment at nm resolution. The proteins exhibit real-time “fingering” fluctuations, which we attribute to dynamic rearrangement of lipid molecules wrapping the proteins. The conformational coordinates of protein transformation obtained from the real-space movies are used as inputs in our molecular dynamics simulations, to verify the driving force underpinning the function-relevant fluctuation dynamics. This platform invites an emergent theme of structural biophysics as we foresee. Host: Bozhi Tian via email at btian@uchicago.edu or at 2-8749. 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

March 10, 2020
GCIS W301 | Tuesday, 3:45 pm

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Cary Forest, UW Madison


Computations in Science

March 11, 2020
KPTC 206 | Wednesday, 12:15 pm

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Peko Hosoi, MIT


Physics Colloquium

March 12, 2020
KPTC 106 | Thursday, 3:30 pm

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Steven Cundiff, Department of Physics, University of Michigan


The Tuesday JFI Seminar

March 17, 2020
GCIS W301 | Tuesday, 3:45 pm

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Nuh Gedik, MIT


Molecular Engineering

March 18, 2020
ERC 161 | Wednesday, 2:00 pm

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Zvonimir Dogic, UC Santa Barbara


Computations in Science

March 25, 2020
KPTC 206 | Wednesday, 12:15 pm

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Madhusudhan Venkadesan, Yale University


Computations in Science

April 1, 2020
KPTC 206 | Wednesday, 12:15 pm

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Taekjip Ha, John Hopkins University


Molecular Engineering

April 1, 2020
ERC 161 | Wednesday, 2:00 pm

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Alexandra Zidovska, NYU


Computations in Science

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

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Gabriel Orebi Gann, UC Berkeley


Physics Colloquium

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

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Mikhail Shapiro, California Institute of Technology


Molecular Engineering

April 15, 2020
ERC 161 | Wednesday, 2:00 pm

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Gary Horowitz, University of California Santa Barbara


Physics Colloquium

April 16, 2020
KPTC 116 | Thursday, 3:30 pm

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Kathrin Velerius, Karlsruhe Institute of Technology


Physics Colloquium

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

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Thomas Rosenbaum, Caltech


Physics Colloquium

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

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Changes of state: a symposium in honor of Thomas F Rosenbaum

This May, please join us for a celebration of the life and work of Thomas F Rosenbaum.

Special Symposium

May 1, 2020
KPTC 106 | Friday, 9:00 am

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Sabetta Matsumoto, Georgia Tech


Computations in Science

May 6, 2020
KPTC 206 | Wednesday, 12:15 pm

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George Malliaris, University of Cambridge


Molecular Engineering

May 6, 2020
ERC 161 | Wednesday, 2:00 pm

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Lance Dixon, Stanford University


Physics Colloquium

May 14, 2020
KPTC 106 | Thursday, 3:30 pm

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JeffFest

JeffFest is a symposium in honor of Jeff Harvey's 65th birthday.
Physics Colloquium

May 15, 2020
KPTC 106 | Friday, 3:30 pm

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Karen Wooley, Texas A&M University


Molecular Engineering

May 20, 2020
ERC 161 | Wednesday, 2:00 pm

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K. Dane Wittrup, MIT


Molecular Engineering

June 3, 2020
ERC 161 | Wednesday, 2:00 pm

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