# Events Archive

## Karri DiPetrillo

#### Off the beaten track: Unconventional Searches at the Large Hadron Collider

We know that the Standard Model cannot be the complete picture of the universe. Countless hints, from natural phenomena like dark matter, to theoretical concerns such as the hierarchy puzzle, strongly suggest that new fundamental particles should appear at energies probed by the LHC. As the LHC transitions from increases in energy to increases in luminosity, it is essential to break long-standing assumptions about how best to look for new physics.

In this talk I will outline a search program for unconventional track-based signatures. These compelling signatures break the underlying assumptions of our experiment's design, and pose tremendous challenges for LHC physicists. I will discuss how to push the boundaries of our current detectors to accelerate our discovery potential in the upcoming run, and touch on ways to improve our detector’s capabilities to look for these signatures at the High Luminosity LHC and beyond.
##### Physics Colloquium

January 24, 2022
Zoom | Monday, 2:00 pm

## Yonglong Xie, Harvard University

#### Probing Quantum Materials with Scanning Probe Microscopy

Electrons inside matter can behave as complex particles that do not exist in the Standard Model. These seemingly impossible effects are examples of emergent phenomena—that is, unexpected collective behavior—of electrons in quantum materials. The discovery and characterization of new emergent phenomena in quantum materials not only expand the boundary of our knowledge, but also provide unique opportunities for future quantum technologies. However, these effects often manifest in subtle ways, and thus detecting them requires developing new, more sophisticated measurement tools.

In this talk, I will demonstrate how a class of experimental techniques called scanning probe microscopy can be a general tool for unlocking new phenomena in quantum materials. To illustrate the power of this approach, I will focus on our recent experimental observation of novel topological quantum states in magic-angle graphene, enabled by scanning single-electron-transistor microscopy. In addition, I will highlight other examples in which scanning probe microscopy permits the discovery of novel phases in other quantum materials. Finally, I will conclude by outlining how pushing the boundaries of existing scanning probe microscopy will enable the discovery and characterization of new emergent phenomena and functionalities in quantum materials, devices, and circuits.
##### Physics Colloquium

January 20, 2022
Zoom | Thursday, 2:00 pm

## falling in a chiral fluid

#### you know... like Icarus

Idle chitchat and munching sounds: noon
Meaningful matters: 12:15
##### MRSEC Baglunch

January 20, 2022
Zoom | Thursday, 12:00 pm

## Xiaomeng Liu, Princeton University

#### Visualizing emergent electron orders in 2D materials

Two-dimensional (2D) materials, such as graphene, are atomically thin crystals exfoliated from layered materials. Recent developments have enabled scientists to isolate 2D materials with various electronic properties and assemble them into van der Waals heterostructures with elaborate arrangements and precise crystalline alignments. This ability to construct materials layer-by-layer has allowed engineering of the band structure and interactions of electrons to cultivate novel quantum states of matter. A plethora of emergent quantum phases have been reported; some notable examples will be introduced in this talk. My presentation will focus on demonstrating scanning tunneling microscopy (STM) and spectroscopy as powerful tools to examine emergent electron orders in 2D materials and 2D heterostructures. In particular, using spectroscopic imaging as a valley probe, we identified valley orders and visualized valley Skyrmions in the graphene quantum Hall ferromagnet. I will also discuss future experiments of exploring emergent quantum phases with STM and transport methods.
##### Physics Colloquium

January 19, 2022
Zoom | Wednesday, 2:00 pm

## Scott J. Miller, Yale

#### Searching for Selective Catalytic Reactions in Complex Molecular Environments

Chemistry Hybrid seminar with (Host: Mark Levin 2-6886)
##### Chemistry Hybrid Seminar

January 14, 2022
Zoom | Friday, 1:45 pm

## Elizabeth Jerison, Stanford

#### Dynamics of Immunity in zebrafish

The immune system is essential to protection against pathogens. Major advances in immunology have identified the components of this complex system. But substantial challenges remain to using this ‘parts list’ to understand immune responses, because the system is at its heart collective, driven by interactions of cells throughout an organism. At the individual cell level, many immune processes are either stochastic or nonlinear; when embedded in the spatial context of an organism, this makes possible rich dynamical behavior. There is widespread optimism that tools from statistical physics may yield new insights into this system. The main roadblock to this approach is the difficulty of observing and perturbing immune responses in vivo, which limits our ability to make quantitative measurements of the dynamics at appropriate time, spatial, and replication scales. I will describe recent progress in developing a zebrafish model system to address this gap. As an example of this approach, I will discuss our observations of the random walk motility of T cells in the live zebrafish, which identified a constrained set of behavioral rules that enables exploration across many length scales. I will also describe recent progress in characterizing spatial control of inflammation in the organism, and conclude by discussing the avenues that this opens for investigating collective transitions in immunity.
##### Special Physics Colloquium

January 12, 2022
Zoom | Wednesday, 2:00 pm

## Alexander Petroff, Clark University

##### Computations in Science

January 12, 2022
KPTC 206 | Wednesday, 12:15 pm

## Edward "Ted" Sargent, Department of Chemistry, Northwestern University

#### Materials Chemistry for Optoelectronics and for Decarbonization

Emerging materials – such as quantum dots, perovskites, and metal and metal oxide nanoparticles – are urgently needed to advance both consumer electronics and large-scale decarbonization of electricity, fuels, and chemicals. I will discuss recent advances in light sensors, LEDs and photovoltaics, and in CO2 reduction electrocatalysts, all enabled by progress in the synthesis and physicochemical understanding of such materials. Host: Dmitri Talapin, 773-702-834-2607 or via email dvtalapin@uchicago.edu. Persons who may need assistance or zoom link information please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu
##### JFI Hybrid Seminar

January 11, 2022
GCIS W301 and Zoom | Tuesday, 4:00 pm

## Annabelle Bohrdt, Harvard

#### Tackling quantum many-body problems with (artificial) intelligence

New quantum simulation platforms provide an unprecedented microscopic perspective on the structure of strongly correlated quantum matter. This allows to revisit decade-old problems from a fresh perspective, such as the two-dimensional Fermi-Hubbard model, believed to describe the physics underlying high-temperature superconductivity. In order to fully use the experimental as well as numerical capabilities available today, we need to go beyond conventional observables, such as one- and two-point correlation functions. In this talk, I will give an overview of recent results on the Hubbard model obtained through novel analysis tools: using machine learning techniques to analyze quantum gas microscopy data allows us to take into account all available information without a potential bias by the choice of an observable and compare different theories on a microscopic level. I will introduce a novel, customized neural network architecture, which features full interpretability and thus enables direct physical insights. The analysis of data from quantum simulation experiments of the doped Fermi-Hubbard model with machine learning tools as well as through different higher-order correlations shows a qualitative change in behavior around 20% doping, consistent with condensed matter experiments on cuprate materials. As an outlook, I will discuss how our microscopic understanding of the low doping limit has led us to the discovery of a binding mechanism, which enables pairing of charge carriers at currently accessible experimental temperatures, thus paving the way for the study of pair formation in cold atom quantum simulators.

##### Special Physics Colloquium

January 11, 2022
Zoom | Tuesday, 2:00 pm

## Kevin Welsher, Duke

#### Untethering single-molecule spectroscopy and capturing the dynamics of extracellular viruses

Capturing dynamic processes occurring at high speeds in living systems is frequently limited by the acquisition time of existing live-cell microscopy methods. This limitation is particularly true in three dimensions, where extended axial sampling reduces the volumetric imaging rate. Here we introduce a new active-feedback 3D microscopy technique that overcomes this 3D imaging speed limit to capture the dynamics of rapidly diffusing single molecules in solution (3D Single-Molecule Active Real-time Tracking or 3D-SMART). This method "locks" target fluorophores in the focal volume of an optical microscope using real-time feedback to move the sample and compensate for molecular diffusion. 3D-SMART has been successfully applied to capture a wide range of targets, from single virus-like particles down to single proteins and nucleic acids at diffusive speeds up to 10 μm2/s. We will further describe how this microscope, when combined with a rapid volumetric imaging method, can capture the early events in the interactions between single viral particles and live cells in three dimensions with millisecond or better temporal resolution.

##### Biophysical Dynamics

January 11, 2022
Zoom | Tuesday, 12:00 pm

## Martin T. Zann, University of Wisconsin - Madison

#### Polaritons enable energy transfer between remote carbon nanotubes as observed with 2D White-Light spectroscopy (plus some nerdy 2D stuff)

Chemistry Hybrid seminar (Host: Sarah King 4-3809)
##### Chemistry Hybrid Seminar

January 10, 2022
Zoom | Monday, 3:45 pm

#### The Crystalline Sponge Method: Enhancing the Technique for Small Molecule Structural Elucidation

Chemistry Hybrid seminar with (Host: John Anderson 2-9025)
##### Chemistry Hybrid Seminar

January 7, 2022
Kent 120 and Zoom | Friday, 1:45 pm

## Stephanie Palmer, University of Chicago

##### Physics Colloquium

January 6, 2022
Zoom | Thursday, 3:30 pm

## 1/f noise in granular conductors

#### does the grain matter?

1/f noise* in granular conductors, does the grain matter?

________
* a puzzling form of electrical noise that whose intensity varies inversely with frequency f and which is often attributed to thermal fluctuations in the resistance of the circuit.

come to the Baglunch zoom room around noon:

Idle chitchat and munching sounds: noon
Meaningful matters: 12:15
##### MRSEC Baglunch

January 6, 2022
Zoom | Thursday, 12:00 pm

## Alison Sweeney, Yale University

##### Computations in Science

January 5, 2022
KPTC 206 | Wednesday, 12:15 pm

#### Optical and Molecular Tools for Mapping Brain Function

Optical tools for simultaneous perturbation and measurement of membrane potential enable spatially resolved mapping of neural activity with high resolution in space and time, in behaving animals. We developed voltage indicators, microscope systems, and analysis software to perform high-resolution recordings in complex tissue environments. With these advanced tools, we are studying the dynamics of microcircuits involved in control of attention and the sub-cellular details of dendritic integration. I will also describe some new approaches to storing brain-wide records of neural activity via intracellular protein "ticker tapes". For any questions please contact Manna Jiang at mjiang2@uchicago.edu or by phone at 773.834.2290
##### PME Distinguished Colloquium

January 5, 2022
Zoom | Wednesday, 11:00 am

## Tiny swimmers that form an active crystal

#### when swallowed in a disorderly phase

iny swimmers that form an active crystal when swallowed in a disorderly phase
come to the Baglunch-oreum around noon:

greeting and reindeer antler hats at 12:00
listening and thinking at 12:15
##### MRSEC Baglunch

December 16, 2021
Zoom | Thursday, 12:00 pm

## Pedram Roushan Senior Scientist, Google

#### Experiments on superconducting processors at the dawn of NISQ era

In 2019, the Google Quantum team demonstrated that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical computer, the quantum supremacy. Going beyond this milestone, we now seek to utilize these Noisy Intermediate Scale Quantum (NISQ) processors to find algorithms that are of interest to the broader scientific community. However, achieving this goal is an outstanding challenge both theoretically, e.g. in finding suitable algorithms, as well as experimentally, e.g. extending coherence of the system. By presenting some of our recent works, we discuss the challenges and our progress. In particular, we present results on preparing the ground state of the Toric code Hamiltonian using an efficient quantum circuit [1]. Combining various techniques, we study transitions to the time crystalline phase [2], which is challenging due to limited programmability, finite coherence time, and finite size of current processors. Our results demonstrate the promise of studying condensed matter problems with NISQ processors.
##### CQE and PME Distinguished Quantum Seminar

December 14, 2021
ERC 161 and Zoom | Tuesday, 10:00 am

## Jim Phillips, Zürich Instruments USA

#### How to Use a Lock-in Amplifier to do Materials Characterization and Chemistry Faster and Better

Electronic measurements for materials characterization and chemistry must detect extremely small signals. For periodic signals, lock-in amplifiers improve sensitivity by orders of magnitude. In this presentation, you will learn about the principles and characteristics of lock-in amplifiers and about applying them to spectroscopy, transport measurements, and measurements in resonators. Host: Sarah B. King,sbking@uchicago.edu or by phone at 773-834-3809. Persons who may need assistance please contact Brenda Thomas at bthomas@uchicago.edu or 773-702-7156.
##### JFI Special Zoom Seminar

December 13, 2021
Zoom | Monday, 10:00 am

## 1st Annual MRSEC Symposium

#### organized by the UChicago MRSEC Graduate Student and Postdoc Advisory (GSPA) Board

The University of Chicago MRSEC would like to announce its 1st Annual MRSEC Symposium organized by the UChicago MRSEC Graduate Student and Postdoc Advisory (GSPA) Board.

Date: Tuesday, December 7, 2021 (In-Person and Virtual)
Event Address: William Eckhardt Research Center- Room 161 and Atrium
(5640 South Ellis Ave. Chicago, IL 60637)

Keynote Speaker: Pro. Mark Hersam, Director of MRSEC at Northwestern University

Register online by November 24th, 2021.
##### Annual MRSEC Symposium

December 7, 2021
WERC 161 and Atrium | Tuesday, 8:00 am

## Martin T. Zanni: University of Wisconsin-Madison

#### Polaritons enable energy transfer between remote carbon nanotubes as observed with 2D White-Light spectroscopy (plus some nerdy 2D stuff)

##### Chemistry Hybrid Seminar

December 3, 2021
Kent 120 and Zoom | Friday, 1:45 pm

## Steven Cundiff, University of Michigan

#### Optical Multi-Dimensional Coherent Spectroscopies

The concept of multidimensional Fourier transform spectroscopy originated in NMR where it enabled the determination of molecular structure. The key concept is to correlate what happens during multiple time periods between pulses by taking a multidimensional Fourier transform. Migrating multidimensional Fourier transform spectroscopy to the optical regime is difficult because phases are critical. I will give an introduction to optical two-dimensional coherent spectroscopy, using an atomic vapor as a simple test system, but also show unexpected results due to atomic interactions. I will then present our use of it to study optical resonances in semiconductor nanostructures.
##### JFI Seminar & Closs Lecture

December 2, 2021
GCIS W301 and Zoom | Thursday, 4:40 pm

## A. Paul Alivisatos, University of Chicago

#### Recent advances in the study of colloidal nanocrystals enabled by in situ liquid cell transmission electron microscopy

Colloidal nanocrystals have emerged as a major building block for nanoscience and nanotechnology. Today it is possible to control the size, shape, and topology of nanocrystals and to harness the variations of their properties to create materials with proven applications in biological imaging and electronic displays, and many more applications under development in renewable energy. Despite these advances, there is much we still do not know about the physical chemistry of nanocrystals. The advent of in situ liquid cell electron microscopy and the graphene liquid cell, have opened a new window into key aspects of the physical chemistry of nanocrystals. Small pockets of liquid, typically just a few tens of nanometer in thickness, and perhaps a few hundred in diameter, can be trapped between single or multiple layers of graphene. These layers are transparent to the electrons of a transmission electron microscope. Inside, we can observe previously hidden properties and events. This includes structural determination of the positions of all the atoms in a colloidal nanocrystal; methods for directly imaging and tracking individual nanocrystals as they move, grow, or dissolve; and the ability to measure the inter-particle potentials by observing pairwise relative motions. This talk will present recent work concerning the nature of the chemical environment and how to manipulate it in order to induce or inhibit chemical reactions. A second aspect will concern the use of machine learning and neural network approaches to analysis of the results of liquid cell TEM experiments. These new tools are enabling a second revolution in the science of nanocrystals, as they will permit to us to quantitatively control artificial colloidal nanoscale building blocks with atomic precision.

When: Dec 2, 2021 03:45 PM Central Time (US and Canada)

Topic: Special Seminar - Prof. Alivisatos

Title of Talk: Recent advances in the study of colloidal nanocrystals enabled by in situ liquid cell transmission electron microscopy

Register in advance for this webinar:

https://uchicagogroup.zoom.us/webinar/register/WN_k13dTVuIQUq8MsNd1Hm5KQ

After registering, you will receive a confirmation email containing information about joining the webinar.
##### Special Seminar

December 2, 2021
Kent 107 and Zoom | Thursday, 3:45 pm

## Matthew Reece, Harvard

#### Title TBD (On Particle Theory)

##### Physics Colloquium

December 2, 2021
KPTC 106 and Zoom | Thursday, 3:30 pm

#### A Statistical (Physics) view of Organismal Development

After a century of biochemical and genetic onslaught on the embryo we are left with an inexhaustive parts list with an increasingly baroque logic. How do we begin to assemble complex living systems from knowledge of their parts list? In this talk, I will attempt to pursue a statistical (physics) approach to discerning the design principles that might be in play in developing organisms. The model system of focus will be the fruit fly's wing, within which we (in collaboration with the Carthew Lab @ NU) pursue a field-theoretic approach to studying the "response function" of the system in response to small, or linear, changes in the genome and environment that the system has evolved to cope with. The central result is an empirical delineation of the manifest degeneracies in the genotype to phenotype map, and an attempt to understand how living matter balances the apparent conflict between the requirements of a robust engineering protocol that permits its self-assembly and the ability to evolve. The hope is that this attempt of ours opens up more questions, rather than give conclusive answers on any matter, yet.
##### Computations in Science

December 1, 2021
KPTC 206 | Wednesday, 12:15 pm

## Ahmad (Mo) Khalil, Boston University

##### Molecular Engineering

November 20, 2021
Zoom | Saturday, 11:00 am

## Kyle Leach, Colorado School of Mines

#### Taming the BeEST: A Model Independent Search for Heavy Neutrinos using Superconducting Quantum Sensors

Host: Young-Kee Kim
The search for sterile neutrinos is among the brightest possibilities in our quest for understanding the microscopic nature of dark matter in our universe. The existence of these elusive particles are best probed indirectly via momentum conservation with SM particles during their possible creation in laboratory through weak-interaction processes. One way to observe these momentum recoil effects experimentally is through high-precision measurements of nuclear electron-capture (EC) decay, where the final state only contains the neutrino and a recoiling atom. This approach is a powerful method in our search for BSM physics since it relies only on the existence of a heavy neutrino admixture to the active neutrinos and not on the model-dependent details of their interactions. In this talk, I will describe our Beryllium Electron capture in Superconducting Tunnel junctions (BeEST) experiment that uses the decay-momentum reconstruction technique to precisely measure the lithium-7 atomic recoil energy in sensitive superconducting tunnel junctions (STJ) following the “kick” it is given by the neutrino in beryllium-7 EC decay. I will also present our first limits on sub-MeV BSM neutrinos and our ongoing work for dramatically increasing the sensitivity of the BeEST. Finally, I will discuss how our pioneering work with this technology can be used to search for BSM physics on the TeV scale with short-lived rare-isotope decay.

Dear Physics Community,

After thoughtful consideration, we have decided not to have indoor receptions following our weekly Physics colloquium. As a result, we will not have a reception for the remaining of the Autumn Quarter. Though we look forward to these gatherings, the health and safety of our community is our highest priority. We will continue to monitor the situation and, when possible, will resume our normal schedule.

Please note, our Physics Tea will continue on Tuesday/Thursday at 3pm in KPTC 206. We’ll offer tea, coffee and take-away snacks. We encourage you to bring your own mugs too!
##### Physics Colloquium

November 18, 2021
KPTC 106 and Zoom | Thursday, 3:30 pm

## Robert Hazen, Carnegie Institute

#### Mineral Informatics: Data-Driven Discovery in Earth & Planetary Materials Research

The story of Earth is a 4.5-billion-year saga of dramatic transformations, driven by physical, chemical, and—based on a fascinating growing body of evidence—biological processes. The co-evolution of life and rocks unfolds in an irreversible sequence of evolutionary stages. Each stage re-sculpted our planet’s surface, while introducing new planetary processes and phenomena. This grand and intertwined tale of Earth’s living and non-living spheres is coming into ever-sharper focus thanks to the emerging field of mineral informatics, which employs powerful analytical and visualization methods applied to large and growing mineral data resources. The histories of terrestrial planets and moons are best preserved in the information-rich record of minerals. Mineral attributes, including trace and minor elements, isotopes, solid and fluid inclusions, structural defects, exsolution and twinning, geologic and petrologic context, and scores of other properties, reveal the ancient origins and complex evolution of Earth’s crust. Thus, mineral informatics is ushering in a new era of discovery, while holding the promise to transform mineralogy into a predictive science.
##### Computations in Science

November 17, 2021
KPTC 206 | Wednesday, 12:15 pm

## Nicholas Lammers, University of California, Berkeley

#### Uncovering the kinetic fingerprints of transcriptional control using gene expression dynamics

Predicting how the gene expression patterns that specify animal body plans arise from interactions
between transcription factor proteins and regulatory DNA remains a major challenge in physical biology. We utilize live imaging, computational modeling, and theoretical approaches to examine how transcriptional control at the single cell level gives rise to a sharp stripe of cytoplasmic mRNA in the fruit fly embryo. We find that the frequency of transcriptional bursts is modulated across the stripe to control the mRNA production rate. In addition to this mean rate modulation, we find that repressors function to control the window of time over which nuclei transcribe by inducing the early cessation of transcription in cells on the stripe flanks.

This all-or-none control of the transcriptional time window is critical to stripe formation, and, in the
normal course of development, appears irreversible. However, by using novel optogenetic tools to
export repressor proteins from silenced nuclei, we reveal that this switch-like silencing is, in fact, rapidly reversible (on timescales of 1-2 minutes), and that it originates from the sharp down-regulation of burst frequency by transcriptional repressors. Thus, we uncover a surprising unity, with both mean rate modulation and control of the transcriptional time window emerging from the same step of the transcriptional cycle.

To close, I outline ongoing theoretical work that moves beyond phenomenological models of
transcriptional bursting to consider a molecular picture of how transcription factor binding transmits information to drive cellular decisions. We demonstrate that the separation of timescales between rapid binding and slow transcriptional bursting can lead to non-intuitive behaviors wherein multiple binding events at a single binding site can regulate multiple stages of the transcriptional cycle. We find that this kinetic cooperativity dramatically increases the rate of information transfer, but only in gene loci that dissipate biochemical energy to operate away from thermodynamic equilibrium.

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

November 17, 2021
GCIS E123 | Wednesday, 10:30 am

## Thomas Kempa, Johns Hopkins University

#### Precision Synthesis of Quantum Material Building Blocks

Quantum materials are poised to transform the development of next-generation sensors, analytical instruments, information processing systems, and energy conversion platforms. Realizing these lofty goals will require low-dimensional crystals whose size, shape, structure, and composition can be tailored to atomic levels of precision. Chemistry will play a vital role in creating these crystalline building blocks of quantum matter. In this vein, the Kempa group has focused on the precision synthesis of 2-dimensional (2D) materials to harness quantum phenomena. Our work with 2D atomic lattices and 2D molecular frameworks has revealed that even subtle manipulations of the dimensionality and morphology of these materials yield substantial property changes. Notably, we can dramatically manipulate the structure of 2D transition-metal dichalcogenides by growing them on chemically tailored surfaces. The resulting nanoribbons emit light whose energy and profile show an unusual progression with crystal size. Seeking to expand the 2D materials landscape, we have also prepared and examined new 2D molecular frameworks. Reversible phase switching can be induced in these frameworks with concomitant modulation of electronic transport. Our efforts underscore the importance of rational synthesis in building low-dimensional materials that enable new discoveries and advance the fields of optics, electronics, energy conversion, and quantum sensing.Host: Bozhi Tian, btian@uchicago.edu or by phone at 773-702-8749. Persons who may need assistance please contact Brenda Thomas at bthomas@uchicago.edu or by phone at 773-702-7156.
##### JFI Emerging Frontiers

November 16, 2021
GCIS W301 and Zoom | Tuesday, 4:00 pm

## Jonathan Colen, University of Chicago

#### Machine learning for Bio-Active Matter

Continuum theories effectively describe many-body systems out of equilibrium in terms of a few macroscopic parameters. Such parameters are difficult to determine from microscopics, particularly in active and biological matter where they are proxies for energy-injecting components. Here, we demonstrate how machine learning can help characterize systems which resist traditional continuum modeling. We use active nematics to demonstrate that neural networks can determine how multiple hydrodynamic parameters change as a function of space and time due to engineered microscopic behavior in experiments. We can also forecast the evolution of these chaotic systems solely from image-sequences of their past, without requiring any knowledge of their underlying physics. We extend our physics-agnostic approach to predict force generation in cells directly from fluorescently-labeled protein distributions. Beyond achieving excellent predictive accuracy, our neural networks also serve as a stepping stone to automatically construct effective continuum equations for cell mechanics. Our study presents neural networks as an integral tool for characterizing diverse active and biological systems, even when no detailed knowledge of their underlying mechanisms exists. Host: Sure Vaikuntanathan, svaikunt@uchicago.edu or by phone at 773-702-7256. Persons who may need assistance please contact Brenda Thomas at bthomas@uchicago.edu or by phone at 773-702-7156.
##### JFI Emerging Frontiers: Statistical Mechanics Guided Machine Learning

November 15, 2021
GCIS W301 and Zoom | Monday, 1:00 pm

## Zachary K. Wickens. Univ. of Wisconsin-Madison

#### Selective synthesis using light and electricity

##### Hybrid Chemistry Seminar

November 12, 2021
Kent 120 and Zoom | Friday, 1:45 pm

## Andrew Sonnenschein, Fermilab

#### Next Generation Axion Dark Matter Searches

Host: Young-Kee Kim
In the early 1980s, axions and WIMPs were identified as promising dark matter candidates. The last forty years have seen a spectacularly successful experimental program attempting to discover the WIMPs, with sensitivity that has by now improved by many orders of magnitude compared to the earliest results. The parallel program to search for axions has made less progress and has reached the necessary sensitivity only over a very limited mass range. However, progress has recently accelerated, with the invention of many new axion detection techniques that may eventually provide a definitive answer to the question of whether the dark matter is made of axions. I will review some of these new developments with emphasis on opportunities for Fermilab and U. Chicago collaboration on the next generation of experiments, including ADMX- Extended Frequency Range and Broadband Reflector Experiment for Axion Detection (BREAD).

Dear Physics Community,

After thoughtful consideration, we have decided not to have indoor receptions following our weekly Physics colloquium. As a result, we will not have a reception for the remaining of the Autumn Quarter. Though we look forward to these gatherings, the health and safety of our community is our highest priority. We will continue to monitor the situation and, when possible, will resume our normal schedule.

Please note, our Physics Tea will continue on Tuesday/Thursday at 3pm in KPTC 206. We’ll offer tea, coffee and take-away snacks. We encourage you to bring your own mugs too!
##### Physics Colloquium

November 11, 2021
KPTC 106 and Zoom | Thursday, 3:30 pm

## Wrinkles and ReLUs

#### Crumpling the plane with neural nets

come to the Baglunch-oreum around noon:

greeting and house tours: 12:00
listening and thinking at 12:15
##### MRSEC Baglunch

November 11, 2021
Zoom | Thursday, 12:00 pm

## Michael Rubenstein, Northwestern University

#### Design and Control of Minimalistic Swarms

Advances in technology have begun to allow for the production of large groups, or swarms, of robots; however, there exists a large gap between their current capabilities and those of swarms found in nature or envisioned for future robot swarms. These deficiencies are the result of two factors, difficulties in algorithmic control of these swarms, and limitations in hardware capabilities of the individuals. Creating a hardware system for large robotic swarms is an open challenge; cost and manufacturability pressure hardware designs to be simple with minimal capabilities, while algorithm design favors more capable hardware. The robot design must balance these factors to create a simple robot that is, at the same time, capable of performing the desired behaviors. In this talk, I will discuss the many challenges associated with creating a robot swarm at this scale and the implications this has for creating even larger, more capable swarms in the future.
##### Computations in Science

November 10, 2021
KPTC 206 | Wednesday, 12:15 pm

## Sarah B. King, University of Chicago

#### Exciton Condensation: What is it? How do you make it? How do you measure it?

Condensation and quantum many-body effects are important in many different scientific disciplines, ranging from condensed matter physics to chemistry. The highly disparate fields that work on condensation phenomena can lead to confusion between researchers with different perspectives, and make it challenging to build collaborations. In this JFI tutorial, I aim to discuss exciton condensation. We’ll discuss questions like: What is an exciton condensate? How can exciton condensates be formed in materials or with molecules? What are the physical characteristics of an exciton condensate that can be measured in a lab? How can we answer the open questions in this emerging field? What are the grand challenges to utilizing exciton condensation for frictionless energy and information transport? This tutorial is open to all – from experts to researchers new to the field. Host: Cheng Chin via email cchin@jfi.uchicago.edu or by phone 773-702-7192. Persons who may need assistance please contact Brenda Thomas at bthomas@uchicago.edu or by phone at 773-702-7156.
##### JFI Emerging Frontier Tutorial: Quantum Many-Body Physics and Chemistry with Ultracold Molecules

November 9, 2021
GCIS W301 | Tuesday, 4:00 pm

#### Structure-Function Relationships of Single Fluorescent Macromolecules

##### Hybrid Chemistry Seminar

November 8, 2021
Kent 120 and Zoom | Monday, 3:45 pm

## Bumpy vs. Smooth Allostery

Bumpy vs. Smooth Allostery
come to the baglunch boutique around noon
greeting and house tours: 12:00
listening and thinking at 12:15
##### MRSEC Baglunch

November 4, 2021
Zoom | Thursday, 12:00 pm

#### Geometry and mechanics of feet and fins

Feet look quite different from fins but face the same structural demand to be sufficiently stiff in order to withstand the forces of propulsion. In this talk, I will show that curvature-induced stiffness is the common principle underlying the stiffness of both primate feet and rayed fish fins. The principle is evident in a drooping currency note or slice of pizza that significantly stiffens upon slightly curling it along the width. We use mathematical analysis, physical mimics, and biological experiments to derive the relationship between curvature and stiffness, and apply this understanding to track the evolution of foot curvature among hominins (human lineage). I will also show how the same principle manifests in fish fins despite their different morphology, with implications for the 380 million year old water-to-land evolutionary transition among vertebrates.
##### Computations in Science

November 3, 2021
KPTC 206 | Wednesday, 12:15 pm

## David Hsieh, California Institute of Technology

#### Strongly Driven Quantum Materials

##### PME Distinguished Colloquium

November 3, 2021
Zoom | Wednesday, 11:00 am

## Renee R. Frontiera, University of Minnesota

#### Spectroscopic Probes of Plasmon-Driven Chemical Reactions

##### Chemistry

November 1, 2021
Kent 120 | Monday, 3:45 pm

## Sidney Redner, Santa Fe Institute

#### First-Passage Processes in Physics and Beyond

A fundamental aspect of a random walk is determining when it reaches a specified threshold position for the first time. This first-passage time, and more generally, the distribution of first passage times underlies many non-equilibrium phenomena, such as the triggering of integrate and fire neurons, the statistics of cell division, and the execution of stock options. The computation of the first-passage time and its distribution is both simple and beautiful, with profound connections to electrostatic potential theory. I will present some aspects of these fundamentals and then discuss applications of first-passage ideas to diverse phenomena, including the stochastic search processes and a toy model of wealth sharing.

##### Physics Colloquium

October 28, 2021
Zoom | Thursday, 3:30 pm

## A robotic blob

come to the baglunch boutique around noon:

greeting and gossiping at noon
listening and thinking at 12:15
##### MRSEC Baglunch

October 28, 2021
Zoom | Thursday, 12:00 pm

## Margaret Gardel, University of Chicago

#### Tissue confinement governs cell size regulation in epithelial tissue

While populations of single-celled organisms increase exponentially, animal cell growth must be coupled to organism growth for tissues to maintain their structure. These spatial constraints lead to a different regime of growth and division regulation known as contact inhibition of proliferation. We still lack a general framework to describe contact inhibition across different biological systems. Here we use model epithelial monolayers with varying spatial constraints to explore how contact inhibition affects cell growth and division. We introduce a concept of tissue confinement which describes the extent to which spatial constraints suppress cell growth in different tissues. Interestingly, confinement has no effect on cell division leading to a decoupling between rates of cell growth and division. In confined tissues cell division outpaces growth causing cell size to decrease. However, when cell size decreases below a specific value cell division becomes arrested. This final cell size is near a physical limit set by the amount of space occupied by DNA in the cell. By perturbing cell division regulation, it is possible to push cells closer to this limit, however, this leads to DNA damage suggesting loss of size regulation could play a role in the development of cancer.
##### Computations in Science

October 27, 2021
KPTC 206 | Wednesday, 12:15 pm

## Julia R. Greer, Caltech

#### Materials by Design: Three Dimensional (3D) Nano-Architected Meta-Materials

Creation of extremely strong and simultaneously ultra lightweight materials can be achieved by incorporating architecture into material design. In our research, we design and fabricate three-dimensional (3D) nano-architected materials that can exhibit superior and often tunable thermal, photonic, electrochemical, biochemical, and mechanical properties at extremely low mass densities (lighter than aerogels), which renders them useful, and often enabling, in many technological applications. Dominant properties of such meta-materials are driven by their multi-scale nature: from characteristic material microstructure (atoms) to individual constituents (nanometers) to structural components (microns) to overall architectures (millimeters and above).

Our research is focused on fabrication and synthesis of nano- and micro-architected materials using 3D lithography, nanofabrication, and additive manufacturing (AM) techniques, as well as on investigating their mechanical, biochemical, electrochemical, electromechanical, and thermal properties as a function of architecture, constituent materials, and microstructural detail. The focus of this talk is on additive manufacturing via function-containing chemical synthesis to create 3D nano- and micro-architected metals, ceramics, multifunctional metal oxides (nano-photonics, photocatalytic, piezoelectric, etc.), shape memory polymers, etc., as well as demonstrate their potential in some real-use biomedical, protective, and sensing applications. I will describe how the choice of architecture, material, and external stimulus can elicit stimulus-responsive, reconfigurable, and multifunctional
##### Closs Lecture

October 26, 2021
GCIS W301 and Zoom | Tuesday, 4:00 pm

## Storing patterns in nonequilibrium conditions

come to the baglunch casbah around noon

greeting and gossiping at noon
listening and thinking at 12:15
##### MRSEC Baglunch

October 21, 2021
Zoom | Thursday, 12:00 pm

## Risi Kondor, University of Chicago

#### Equivalent Neural Networks for Modeling Physical Interactions: Curve Fitting or a New Way of Understanding Nature

In the last few years there has been an explosion of interest in using machine learning for modeling physical and chemical systems. Research in this field ranges from using ML tools narrowly, such as to just learn the force fields that are plugged into a molecular dynamics simulation system, to trying to use AI as a drop-in replacement for PDE solvers or entire protein structure prediction pipelines. Many researchers feel that the most productive way to harness AI in science will be to tightly couple physical modeling with the more statistical, data driven pilosophy of ML. One small step along this way has been the development of equivariant neural networks, which are able to explicitly account for some physical symmetries and conservation laws. In this talk I will give a broad, somewhat mathematical, introduction to this subject and illustrate it with some examples. Host: Sure Vaikuntanathan, svaikunt@uchicago.edu. For persons who may need assistance contact Brenda Thomas at bthomas@uchicago.edu
##### JFI Emerging Frontiers

October 19, 2021
GCIS W301 and Zoom | Tuesday, 4:00 pm

## Andy McNally, Colorado State University

#### Selective Functionalization of Pyridines, Diazines and Pharmaceuticals via Unconventional Intermediates

##### Chemistry

October 15, 2021
Zoom | Friday, 1:45 pm

## Soft Matter for All

##### Special Virtual Seminar

October 15, 2021
Zoom | Friday, 9:00 am

## David Grier, New York University

#### Tractor Beams and Related Topological Waves

Introducing topological defects into the wavefronts of traveling waves endows them with surprising and useful properties including quantized angular momentum, freedom from diffraction and apparent force-free acceleration. Recent advances in the theory of photokinetic effects reveal how wavefront topology can be harnessed to create practical tractor beams, thereby transforming science fiction tropes into functional tools for research and exploration.
##### Physics Colloquium

October 14, 2021
Zoom | Thursday, 3:30 pm

## How particles twirl and swirl in 3D

#### in a rhythmic magnetic field

How particles twirl and swirl in 3D in a rhythmic magnetic field

time is unchanged: gathering at noon. listening and thinking at 12:15

This time it's straight zoom. See you Thursday
##### MRSEC Baglunch

October 14, 2021
Zoom | Thursday, 12:00 pm

## Laura H. Greene, National MagLab, Florida State University

#### Local Moment Pairing in the Heavy-Fermion Superconductor CeCoIn_5

The heavy-fermion superconductor CeCoIn5 has a pairing symmetry of dx2-y2 but the pairing mechanism remains unknown. Our planer tunneling spectroscopy measurements on single crystals into the three major crystallographic orientations as a function of temperature down to 20 mK and fields up to 18 T are reproducible, and our diagnostics show transport across the barrier is predominately single-step elastic tunneling. [1] At low temperatures, on the (100) and (001) faces, we find sharp coherence peaks with an estimated gap of 0.65 meV, and on the (110) face, a broad zero-bias peak. Previously published STM work reports observing pair potentials above Tc = 2.3 K [2]; we also find pre-formed pairs up to Tp ~ 5 K. Below Tp, with increasing applied field, the pairing gap evolves smoothly to a field-induced gap, that grows linearly up to 18 T, the highest field measured. At higher temperatures, no field-induced gap is observed, showing that pairing and the field-induced gap exist concomitantly. Kondo scattering plays a role in the pairing mechanism, and composite pairing remains a possible explanation. [3]
Host: Peter Littlewood, 773-834-4879 or via email at littlewood@uchicago.edu. Persons who may need assistance contact Brenda Thomas at 773-702-7156 or via email at bthomas@uchicago.edu.
##### JFI Special Seminar

October 8, 2021
GCIS W301 | Friday, 3:00 pm

## Laura Greene, National MagLab and Florida State University

#### The Dark Energy of Quantum Materials

The nearly 80-year-old correlated electron problems remain largely unsolved; with one stunning success being BCS electron-phonon mediated conventional superconductivity. There are dozens of families of superconductors that are unconventional, including the high-Tc cuprate and iron-based, and heavy fermion superconductors. Although these materials are disparate in many of their properties, some of their fundamental characteristics are strikingly similar, including their ubiquitous phase diagram, with intriguing correlated-electron (not-Fermi liquid) phases at temperatures well above the superconducting transition. These remain among the greatest unsolved problems in physics today; and I will present an analogy stressing that. I will also give a short overview of the US National MagLab and mention some of our own recent work on identifying a possible new pairing mechanism in a heavy-fermion superconductor.
##### Physics Colloquium

October 7, 2021
Zoom | Thursday, 3:30 pm

## Contact inhibition pt. 2

#### squishy cells in an expanding world

Contact inhibition pt. 2: squishy cells in an expanding world

time is unchanged: gathering at noon. listening and thinking at 12:15

Let us resume!
##### MRSEC Baglunch

October 7, 2021
Zoom | Thursday, 12:00 pm

## John Anderson, University of Chicago

#### Leveraging Exotic Electronic Structures in Transition Metal Molecules and Materials

Disparate fields including catalysis, biology, and materials chemistry all rely upon transition metals. Decades of research have yielded deep insights into how the electronic structure of metal centers dictates their properties and reactivity. However, transforming these deep insights into tractable strategies for new transformations or functionality remains an outstanding challenge. I will present our group’s progress at not only uncovering, but leveraging, new electronic structure paradigms in this area. I will show how an unusual Co–O bond has triggered a reconsideration of classic dogmas in transition metal oxo mediated CPET reactions. We show that semiclassical transition state theory contributions can dictate selectivity even in nonadiabatic CPET reactions. Furthermore, generation of even more oxidized Co–O cores results in hydroxylation with rates comparable to the fastest biological systems. I will then cover our efforts in expanding proton storage and electron delocalization across conjugated ligand frameworks. This strategy enables new pathways for the activation of oxygen and also leads to highly efficient reductive and aerobic catalysis. Finally, I will show how expanding electron delocalization across even longer length scales enables the tuning of macroscopic material properties. Unusual diradical electronic structures offer exciting possibilities for near-IR emission, qubits, and new bulk properties even in amorphous materials. While varying in length and localization from a single bonding interaction to macroscopic charge transport, all these advances are rooted in understanding and utilizing unusual electronic structures of transition metal centers and their coordination spheres.
##### Chemistry

October 4, 2021
Zoom | Monday, 3:45 pm

## Hans Renata, Scripps Research Institute

##### Chemistry

October 1, 2021
Zoom | Friday, 1:45 pm

## Jack W. Szostak, Harvard University

#### Physics and the Origin of Life

A wide range of physical processes played important roles in the origin of life. On a planetary scale, large impacts both altered the chemistry of the atmosphere and created surface environments that may have nurtured the earliest forms of life. On a smaller scale, freeze-thaw and wet-dry cycles concentrated dilute chemicals and drove important reactions; the crystallization of key compounds created reservoirs of organic minerals and may also have led to the molecular asymmetry (or homochirality) that is a hallmark of life. Finally, at an even smaller scale, the operation of Darwinian evolution led to the gradual accumulation of the information, digitally encoded in the sequences of RNA and DNA molecules, that is an essential characteristic of biology.
##### Physics Colloquium

September 30, 2021
KPTC 106 | Thursday, 3:30 pm

## Quantum Creators Prize

##### Special Virtual Seminar

September 29, 2021
Zoom | Wednesday, 9:00 am

## Taeghwan Hyeon, SNU Distinguished Professor, Seoul National University

#### Designed Synthesis and Assembly of Inorganic Nanomaterials for Energy and Soft-Electronics Applications

Recently we have focused on the architecture engineering of inorganic nanomaterials for their applications to fuel cell electrocatalysis, lithium ion battery, and photocatalysis. We present a synthesis of highly durable and active electrocatalysts based on ordered fct-PtFe nanoparticles for ORR electrocatalysts for fuel cells. We report on the design and synthesis of highly active and stable Co-N4(O) moiety incorporated in nitrogen-doped graphene (Co1-NG(O)) for electrochemical H2O2 production. We report on the design and synthesis of highly active TiO2 photocatalysts incorporated with site-specific single copper atoms (Cu/TiO2) for photocatalytic hydrogen generation activity. We synthesized multigrain nanocrystals consisting of Co3O4 nanocube cores and Mn3O4 shells. We fabricated ultraflexible/stretchable electronic devices integrated with various functional nanomaterials and their applications to wearable and implantable medical and healthcare devices. We introduced electromechanical cardioplasty using an epicardial mesh made of electrically conductive and elastic Ag/Au nanowire-rubber composite material. Host: Jiwoong Park, 773-834-3179 or via email at jwpark@uchicago.edu. Persons who may need assistance contact Manna Jiang at 773.834.2290 or via email at mjiang2@uchicago.edu. REGISTER IN ADVANCE FOR THIS SEMINAR:
https://uchicagogroup.zoom.us/webinar/register/WN_odY78oGzRqWudhjdVAwTrw
##### PME/Chemistry Joint Zoom Seminar

September 23, 2021
Zoom | Thursday, 2:00 pm

## Rising Stars Symposium in Soft and Biological Materials

The NSF Materials Research Science and Engineering Centers at Princeton, University of Chicago and University of Delaware will hold symposia and career workshops geared for early career researchers in Soft and Biological Matter during Fall 2021. All events will be virtual.
##### Special Virtual Seminar

September 23, 2021
Zoom | Thursday, 9:00 am

## Rising Stars Symposium in Experimental Particle Physics

We are very excited to host a special Symposium on September 22nd--23rd, 2021 highlighting early-career researchers working in exciting new directions in various areas of experimental particle physics.

In addition to individual presentations, the speakers and the audience will collectively participate in a discussion on future directions of the field towards the end of the symposium.

Please register at the following event site and join us for what will certainly be an invigorating and inspiring event.

https://indico.uchicago.edu/e/RisingStarsParticlePhysics2021

This Symposium is jointly hosted by the EFI and Physics Departments, so please do attend!
##### Special Virtual Seminar

September 22, 2021
Zoom | Wednesday, 9:00 am

## Driving 2D nanosheet on water with light

Baglunch shifts to NEW DAY: Thursdays*

time is unchanged: gathering at noon. listening and thinking at 12:15

Driving 2D nanosheet on water with light
##### MRSEC Baglunch

September 16, 2021
Zoom | Thursday, 12:00 pm

## Does transmembrane electric potential modulate fluidity of bilayer membranes?

Stay for the discussion at 12:15 on whether ...
transmembrane electric potential modulates fluidity of bilayer membranes
##### MRSEC Baglunch

September 10, 2021
Zoom | Friday, 12:00 pm

## Coupled but disordered, ordered but lonely…

#### must my nanoparticles choose?

Join us at noon Chicago time to meet, greet and settle in.

Stay for the discussion at 12:15 on
Coupled but disordered, ordered but lonely…must my nanoparticles choose?
##### MRSEC Baglunch

August 27, 2021
Zoom | Friday, 12:00 pm

## Yitzhak Rabin, Physics, Bar-Ilan University

#### Aggregation of intrinsically disordered proteins: from nucleoporins to associative polymers

Note special day and time.
come at 1 Monday July 26 to meet Yitzhak and socialize. The proceedings will begin in earnest at 1:15

BONUS: Yitzhak will be on campus and available s speak with people after his talk.
##### MRSEC Baglunch

July 26, 2021
Zoom | Monday, 1:00 pm

## Celebration of Life for R. Stephen Berry

The program of speakers will last approximately one hour.

Sunday, July 25, 11 am CST

https://uchicago.zoom.us/j/99972545915?pwd=d3pzQ3lkMnZqUDk1SVFPR3UxTWlydz09#success

##### JFI Special Event

July 25, 2021
Zoom | Sunday, 11:00 am

## Contact inhibition

#### how small will a cell squeeze down?

Stay for the discussion at 12:15 on
contact inhibition: how small will a cell squeeze down?
##### MRSEC Baglunch

July 23, 2021
Zoom | Friday, 12:00 pm

## Flow singularities in soft materials

#### from thermal motion to active molecular stresses

This Friday we get to see a new local measurement methodology and give our thoughts about it.

Stay for the discussion at 12:15 on
Flow singularities in soft materials: from thermal motion to active molecular stresses
##### MRSEC Baglunch

July 16, 2021
Zoom | Friday, 12:00 pm

## kicking oscillators (eg neurons) into sync

#### a little chaos wouldn't hurt

A little partying at noon [a little chaos will not hurt]

A little discussion at 12:15 [likewise]
##### MRSEC Baglunch

July 9, 2021
Zoom | Friday, 12:00 pm

## Sung Kim, Howard University

#### Characterization of oritavancin mode of action and Staphylococcus aureus peptidoglycan structure by solid-state NMR

Solid-state NMR was used to characterize the mode of action of oritavancin, a second-generation glycopeptide antibiotic reserved for the treatment of serious infections by multi-drug resistant Gram-positive pathogens. Oritavancin inhibits bacterial cell wall biosynthesis by targeting the nascent peptidoglycan. Rotational-echo double resonance (REDOR) NMR was used to determine the internuclear distances from the 19F of oritavancin to the specific 31P, 13C, and 15N labels that are incorporated into the cell walls of Staphylococcus aureus. 13C{15N} and 15N{13C} REDOR NMR confirmed that the potent bactericidal activity of oritavancin is due to dual inhibition of transglycosylation and transpeptidation steps of peptidoglycan biosynthesis by targeting the lipid transporter C55. Since C55 is a shared transporter required for both peptidoglycan and wall teichoic acid (WTA) biosyntheses, we found that S. aureus treated with a sub-inhibitory concentration of oritavancin rapidly inhibited WTA biosynthesis, but without detectable changes to the peptidoglycan cross-link or stem-link densities. The result is consistent with oritavancin targeting WTA prior to the peptidoglycan biosynthesis in S. aureus.
##### Physics Colloquium

June 10, 2021
Zoom | Thursday, 3:30 pm

## Andre de Gouvea, Northwestern

#### Majorana or Dirac, That is the Question

Among the most pressing questions in fundamental particle physics today is revealing the nature of neutrinos: are they Dirac fermions or Majorana fermions? I attempt to justify why this is the case and expand on what the question means. Then, I discuss different ways to answer the question, exploring both well known, realistic solutions — searches for lepton-number violation — and less well known, idealistic probes that are, nonetheless, interesting from a more pedagogical point of view
##### Physics Colloquium

June 3, 2021
Zoom | Thursday, 3:30 pm

#### Metrology and Entanglement with Assembled Arrays of Atoms

Quantum science with neutral atoms has seen great advances in the past two decades. Many of these advances follow from the development of new techniques for cooling, trapping, and controlling atomic samples. As one example, the technique of optical tweezer trapping of neutral atom arrays has been a powerful tool for quantum simulation and quantum information, because it enables control and detection of individual atoms with switchable interactions. In this talk, I will describe ongoing work at JILA where we have explored a new direction for the optical tweezer platform: metrology. I will report our recent progress towards combining scalability and quantum coherence in a tweezer-based optical atomic clock platform, and our results in using quantum information concepts and many-body dynamics to create entangled states that enhance metrological performance. Much of this technology is based in the use of tweezer-trapping of a new family of atoms, alkaline-earth atoms — I will discuss the broader outlook of this direction and new pursuits on the horizon.
##### JFI Zoom Seminar

June 1, 2021
Zoom | Tuesday, 3:45 pm

## auxetic curvature in crumpled nanosheets

Come and say hi at noon

The story begins at 12:15
##### MRSEC Baglunch

May 28, 2021
Zoom | Friday, 12:00 pm

## Ethan Silva (Performance Structures)

#### Materializing Visions

I will use examples from my own life, explaining the process as it applied to a few of the projects I have built.
In each case, the process of making the vision real, or material, required the many dimensions of: form, function, material properties, engineering, physics, aesthetics, artistry, craft, personnel, budget, and luck. I will explain how these factors intertwined during the building process to influence the completed realization of the visions.

Ethan A. Silva has over forty years’ experience in the design, construction, and installation of complex structural projects for the entertainment industry, the arts, and in boat building and design. Past projects include major attractions for the Atlanta Olympic City, Disney World Orlando, Universal Studios, Fox Studios Australia Titanic Experience, and structural effects for the world tours of Pink Floyd, U2, and the Rolling Stones. Performance Structures, Inc. founded in 1992 by Mr. Silva, is probably best known for fabricating Cloud Gate (the “Bean”) at Chicago’s Millennium Park.
##### Physics & Contemporary Architecture Guest Lecture Series

May 27, 2021
Zoom | Thursday, 5:30 pm

## Walter E Massey

#### Reflections on a Full, Consequential, and Lucky Life: Science, Leadership, and Education

Referencing John Dewey: "the inclination to learn from life itself and to make the condition of life such that all will learn the process of living is the finest product of schooling," Walter Massey shares experiences fro a variegated set of institutions and circumstances, including a 55-year association with the University of Chicago in multiple capacities.

Questions to be reflected on include:

How does growing up in rigidly and dangerously segregated Mississippi in the forties and fifties, cutting lcasses and playing alto saxophone in a rhythm and blues band, lead to becoming a theoretical physicist?
How did and academic scientist, who never took a business or finance course become chairman of Bank of America, at the time the largest bank in the nation, in the midst of global financial crisis?
How did a theoretical physicist become president of one of the nation's Premier schools of Art and Design?
What is the impact of a liberal education and scientific career on shaping a life of consequence?
Why is diversity and inclusion in science more important now than ever?
What does luck have to do with it?
Followed by a conversation with Don Michael Randel.
##### Physics Colloquium

May 27, 2021
Zoom | Thursday, 3:30 pm

## Jennifer Ogilvie, University of Michigan

#### Shedding New Light on Photosynthetic Systems Using Multidimensional Spectroscopies

The primary events of photosynthesis occur on ultrafast timescales with high quantum efficiency. Elucidating the design principles of photosynthetic systems remains an outstanding challenge that has the potential to impact our design of artificial light-harvesting materials. I will demonstrate how multidimensional spectroscopy can address open questions about photosynthetic systems and describe our recent progress in developing and using these tools to probe the mechanisms of ultrafast energy conversion in natural photosynthetic systems. Host: Melissa Bodine, mbodine@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at bthomas@uchicago.edu.
##### JFI Zoom Seminar

May 25, 2021
Zoom | Tuesday, 3:45 pm

## Rifts, rafts and the scaling of the texture length

Come and say hi at noon

The story begins at 12:15
##### MRSEC Baglunch

May 21, 2021
Zoom | Friday, 12:00 pm

## Jeanne Gang (Studio Gang)

#### Strength in the Fluid, Soft, and Yielding

The talk focusses on a collection of projects that explore ideas, materiality, and the process of design. While architecture is traditionally thought to be materially solid and permanent, there is a growing interest in other materials and structures that have a range of qualities driven by different criteria. At the same time, the process of design itself is changing, becoming more inclusive and less rigid. We will ask: What kind of architecture will emerge from these changes?

Use this link to register: https://uchicago.zoom.us/meeting/register/tJAvceirpjkrHdAmjTAxgtrgzJo23cRGjdAA
##### Physics & Contemporary Architecture Guest Lecture Series

May 20, 2021
Zoom | Thursday, 5:30 pm

## Richard Beyler, Portland State U.

#### The “Inner Necessity” of a Reluctantly Public Intellectual: James Franck as a Leader of the Physics Community under Political Pressure

James Franck evidently did not aspire to be a public intellectual. If anyone comes close to Max Weber’s ideal separation between science and politics, it is this consummate experimentalist. Yet in critical situations, Franck was called upon to act as a spokesperson for his professional community. In the words of his resignation letter in the face of the Nazi purges, he felt an “inner necessity” to confront concerns that went far beyond the walls of the laboratory. In this presentation, I review Franck’s decisive rejoinder to Nazi ideology in 1933, his work to rebuild a research community in exile, and his role in creating the eponymous report on nuclear weapons at the end of World War II‒comparing these responses both to each other, and to the range of responses shown by other scientists at the time.

##### Physics Colloquium

May 20, 2021
Zoom | Thursday, 3:30 pm

## Eric Shaqfeh, Stanford

#### Particle Suspensions in Elastic Fluids

Rigid or flexible particles suspended in viscoelastic fluids are ubiquitous in the food industry (e.g. pastes), industrial molding applications (all composites and 3-D printed parts), the energy industry (e.g. fracking fluids), and biological fluids (i.e. swimming of bacteria in mucous). The mathematical description of these suspensions is in its infancy. For example, the foundational work in Newtonian suspensions was accomplished by Einstein in 1905 , but that same calculation in an elastic fluid appeared in 2018 (!) However, the real breakthrough has been the development of a computational simulation of such viscoelastic suspensions, with particle level resolution. These simulations will allow the principles which govern the simplest flows of such suspensions, which are now only beginning to be understood, to become elucidated in the next decade. I will describe a series of foundational problems that have now been analyzed using these new computational methods including comparison to existing experiments. I will then discuss those problems that represent “the next steps” in the field.
##### MRSEC Baglunch

May 14, 2021
Zoom | Friday, 12:00 pm

## Eric S.G. Shaqfeh, Stanford University

#### Particle Suspensions in Elastic Fluids

Rigid or flexible particles suspended in viscoelastic fluids are ubiquitous in the food industry (e.g. pastes), industrial molding applications (all composites and 3-D printed parts), the energy industry (e.g. fracking fluids), and biological fluids (i.e. swimming of bacteria in mucous). The mathematical description of these suspensions is in its infancy. For example, the foundational work in Newtonian suspensions was accomplished by Einstein in 1905, but that same calculation in an elastic fluid appeared in 2018 (!) However, the real breakthrough has been the development of a computational simulation of such viscoelastic suspensions, with particle level resolution. These simulations will allow the principles which govern the simplest flows of such suspensions, which are now only beginning to be understood, to become elucidated in the next decade. I will describe a series of foundational problems that have now been analyzed using these new computational methods including a comparison to existing experiments. I will then discuss those problems that represent “the next steps” in the field.
##### Computations in Science

May 14, 2021
Zoom | Friday, 12:00 pm

## David Benjamin (The Living)

#### Living Materials

David Benjamin’s work combines research and practice, with a focus on an expanded and actionable framework of environmental sustainability. This talk will describe the use of machine learning and repurposed wood to create a building facade for Princeton University, and the invention of structural bricks made of mushrooms and agricultural waste to make a 40-foot-tall tower with no carbon emissions for the Museum of Modern Art. More broadly, it will explore how non-uniform, living materials—and formerly living materials—can present both challenges and opportunities in relation to engineering and the way humans live.

Use this link to register: https://uchicago.zoom.us/meeting/register/tJAvceirpjkrHdAmjTAxgtrgzJo23cRGjdAA

The lecture series is supported by the College Curricular Innovation Fund and organized in cooperation with the Art, Science + Culture Initiative at The University of Chicago. For information on the lecturers, see the attached pdf file.
##### Physics & Contemporary Architecture Guest Lecture Series

May 13, 2021
Zoom | Thursday, 5:30 pm

## Gary Horowitz, University of California, Santa Barbara

#### Black Holes and Spacetime Singularities

One of the most profound predictions of Einstein’s theory of general relativity is the existence of black holes. Despite recent data coming from gravitational wave detectors and the Event Horizon Telescope, there are still fundamental mysteries about these objects. I will start by describing some of these mysteries and recent progress toward understanding them, but then turn to something even more exotic. Inside black holes are spacetime singularities: regions where general relativity breaks down and must be replaced by a quantum theory of gravity. It may be possible for these singularities to also occur outside black holes, where they could be seen by distant observers. I will describe some attempts to find examples of these so-called “naked” singularities.
##### Physics Colloquium

May 13, 2021
Zoom | Thursday, 3:30 pm

## ze demon is in za detailed balance

#### verstest-du?

meet: 12:00
Greet: 12:01
eat: 12:02
...
treat: 12:15
##### MRSEC Baglunch

May 7, 2021
Zoom | Friday, 12:00 pm

## William Baker (Skidmore, Owings & Merrill)

#### Architecture, Structure and the Geometry of Equilibrium

Geometry is at the intersection of architecture and structure; structures are driven by physics. In this talk, we will explore how the geometry of buildings and bridges respond to the forces of nature. We will even show how one can derive some basic building forms using only a pencil, ruler and straight edge.

Use this link to register: https://uchicago.zoom.us/meeting/register/tJAvceirpjkrHdAmjTAxgtrgzJo23cRGjdAA

The lecture series is supported by the College Curricular Innovation Fund and organized in cooperation with the Art, Science + Culture Initiative at The University of Chicago. For information on the lecturers, see the attached pdf file.
##### Physics & Contemporary Architecture Guest Lecture Series

May 6, 2021
Zoom | Thursday, 5:30 pm

## John Teufel, NIST/Boulder

#### Title TBA

##### Physics Colloquium

May 6, 2021
Zoom | Thursday, 3:30 pm

## Kathrin Valerius, Karlsruhe Institute of Technology

#### Probing the neutrino mass with tritium beta decay

Precision measurements of the kinematics of weak decays offer a direct and nearly model independent approach to probe the absolute neutrino mass scale. The KArlsruhe TRItium Neutrino experiment (KATRIN) is searching for the minute imprint of the neutrino mass in the endpoint region of the tritium beta-decay spectrum. KATRIN employs a high-intensity gaseous molecular tritium source and a high-resolution electrostatic filter with magnetic adiabatic collimation to target a neutrino-mass sensitivity of 0.2eV/c2, thus improving on previous experiments by an order of magnitude, after five years of data-taking.

With just its first science run, KATRIN has improved previous direct neutrino mass bounds by about a factor of two, yielding a new upper limit of 1.1 eV/c2 (90% CL), and has begun to address further science channels such as the direct search for light sterile neutrinos. As larger data sets are collected and further improvements in terms of signal-to-background ratio and systematics are being achieved, KATRIN is continuing along its path towards sub-eV neutrino mass sensitivity and the exploration of interesting BSM physics cases.
##### Physics Colloquium

April 29, 2021
Zoom | Thursday, 3:30 pm

## Taekjip Ha, Johns Hopkins University

#### Conformational control: from single molecules to biotechnologies

It has been known over forty years that proteins have multiple conformations. How these conformations are related to function and how to exploit our understanding of conformational control to create novel behaviors and biotechnologies is an active area of research. I will illustrate two examples, CRISPR Cas9 and helicases, where biophysical understanding of regulatory mechanisms led to the creation of new biotechnologies through chemically or light-induced conformational control. Host: Jun Huang. For More info: https://biophysics.jhu.edu/directory/taekjip-ha/
##### Molecular Engineering

April 28, 2021
Zoom | Wednesday, 11:00 am

## No bones, no problem

#### a dive into octopus arm motor control

Noon: dynamic self organization
12:15 the self-organized entity ventures forth
##### MRSEC Baglunch

April 23, 2021
Zoom | Friday, 12:00 pm

## Caterina Doglioni, Lind U.

#### Title TBA (HEP experiment)

##### Physics Colloquium

April 22, 2021
Zoom | Thursday, 3:30 pm

## Libai Huang, Purdue University

#### Ultrafast Dynamic Microscopy of Exciton and Charge Transport

Long-range propagation of energy and information is highly desirable for solar energy harvesting and quantum information applications. However, there currently lacks experimental tools to investigate transport with high temporal and spatial resolutions to directly elucidate coherent and incoherent regimes. To address this challenge, my research group has developed ultrafast microscopy tools to image energy transport in molecular and nanostructured materials with simultaneously high spatial and temporal resolutions.

In my talk, I will focus on our recent progress on the visualization of exciton and charge transport in the nonequilibrium and coherent regimes. One example is the quasi-ballistic transport of hot carriers in hybrid perovskite materials, which leads to 230 nanometers transport distance in 300 fs. These results suggest potential applications of hot carrier devices based on hybrid perovskites. Another example is the transport of delocalized excitons in molecular aggregates. Our measurements demonstrated that delocalization can greatly enhance exciton diffusion, even when the excitons are only weakly delocalized (< 10 molecules). Finally, I will discuss nonequilibrium transport resulting from many-body exciton interactions. We have shown that the migration of interlayer excitons in WS2-WSe2 heterobilayers is controlled by the interplay between the moiré potentials and strong many-body interactions, leading to exciton-density- and twist-angle-dependent transport length that deviates significantly from normal diffusion.
##### JFI Zoom Seminar

April 20, 2021
Zoom | Tuesday, 3:45 pm

## Searching for Dark Particles with Light with Quantum Technologies

#### Roni Harnik, FNAL

Some of the well motivated extensions of the Standard Model of particle physics involve the existence of new light particles that interact with photons. I will present new efforts and ideas to search for these states which harness the technologies of quantum information science. I will focus on two search strategies: light shining through wall experiments which employ superconducting cavities, and nonlinear optics experiments in which missing energy may be searched for at the optics table.
##### Physics Colloquium

April 15, 2021
Zoom | Thursday, 3:30 pm

## Lu Wang, Rutgers University

#### Modeling the Quantum Effects and Vibrational Spectroscopy of Biomolecules

Short hydrogen bonds, which have the heteroatom distances below 2.7 Å, occur extensively in organic small molecules and biological macromolecules. In the first part of the talk, I will discuss the structural and chemical features of short hydrogen bonds from our recent statistical analysis of the Protein Data Bank. From electronic structure calculations, we show that short hydrogen bonds in proteins exhibit considerable quantum mechanical characters and share common features in their proton potential energy surfaces. We have further carried out first principles simulations on a set of model molecules that mimic these biological short hydrogen bonds and elucidated how electronic and nuclear quantum effects promote the sharing of the proton in the hydrogen bonds and lead to distinctive 1H NMR chemical shifts. These findings will facilitate the investigation of the structure and functional roles of short hydrogen bonds in biological systems.

Linear and non-linear vibrational spectroscopy provides a powerful tool to probe the structure and conformational dynamics of nucleic acids. In the second part of my talk, I will describe our recent progress on the modeling of vibrational spectra of nucleic acids. We have developed vibrational frequency maps and coupling models that allow one to calculate the vibrational Hamiltonian, and thus the vibrational spectra, of nucleic acids in the base carbonyl stretch region directly from MD simulations. Using a set of nucleobase derivatives and oligonucleotides, I will show that the predicted IR spectra in the 1600 – 1800 cm-1 region are in quantitative agreement with the experiment measurements. Our theoretical methods effectively connect MD simulations and spectroscopy experiments, which will provide molecular-level insight into the origin of the observed vibrational spectra of nucleic acids.
##### JFI Zoom Seminar

April 13, 2021
Zoom | Tuesday, 3:45 pm

## Gabriel Orebi Gann, UC Berkeley

#### Let There be Light: unlocking the secrets of the Universe with neutrinos

Neutrinos are some of the most fascinating particles that occur in nature. Over one billion times lighter than the proton, the neutrino was once thought to be massless and to travel at the speed of light. The Nobel-Prize winning discovery of neutrino oscillations told us that neutrinos have non-zero mass, which opens up the unique possibility of the neutrino being its own antiparticle, known as a Majorana fermion. This property could help explain the dominance of matter in our Universe. This talk will discuss the benefits of different experimental approaches for using light to observe neutrinos, and the physics thus enabled: from directional Cherenkov detectors like the Sudbury Neutrino Observatory, to its successor experiment, SNO+, which uses scintillation to probe low-energy interactions. We will then discuss technological advances that could enable a new kind of hybrid neutrino experiment: the THEIA detector would be capable of combining both signals to achieve unprecedented physics reach across low- and high-energy neutrino and rare-event physics.

##### Physics Colloquium

April 8, 2021
Zoom | Thursday, 3:30 pm

## Pratyush Tiwary, University of Maryland, College Park

#### Can artificial intelligence help understand and predict molecular dynamics?

The ability to rapidly learn from high-dimensional data to make reliable predictions about the future is crucial to life. This could be a fly avoiding predators, or the retina processing terabytes of data guiding complex human actions. Modern day artificial intelligence (AI) aims to mimic this fidelity and has been successful in many domains. It is tempting to ask if AI could also be used to understand and predict the dynamics of complex molecules with millions of atoms. In this talk I will show that certain flavors of AI can indeed help us understand generic molecular dynamics and also predict it even in situations with arbitrary long memories. However this requires close integration of AI with old and new ideas in statistical mechanics. I will talk about such methods developed by my group (1-3). I will demonstrate the methods on different problems, where we predict mechanisms at timescales much longer than milliseconds while keeping all- atom/femtosecond resolution. These include ligand dissociation from flexible protein/RNA and crystal nucleation with competing polymorphs. I will conclude by discussing some generic challenges and solutions regarding reliability, interpretability and extrapolative powers of AI when used in molecular simulations.
##### Chemistry

April 5, 2021
Zoom | Monday, 4:00 pm

## Never before, never again

#### the singular 2021 March meeting debrief

Never before, never again: the singular 2021 March meeting debrief
##### MRSEC Baglunch

March 26, 2021
Zoom | Friday, 12:00 pm

## Joel Coley, Howard University

#### A Study of Superorbital Modulation in Wind-fed Supergiant X-ray Binaries

X-ray binary star systems consisting of highly magnetized neutron stars and massive stellar companions are important astrophysical laboratories to study accretion physics in the presence of strong electromagnetic and gravitational potentials. The light curves and spectra of neutron star X-ray binaries shows variability on a number of different timescales including their neutron star rotation periods, their binary orbits and in some cases on superorbital timescales. Only six wind-fed Supergiant X-ray binaries have been found to show superorbital modulation. In this talk, I present Nuclear Spectroscopic Telescope Array (NuSTAR), Neil Gehrels Swift Observatory (Swift) X-ray Telescope (XRT) and Swift Burst Alert Telescope (BAT) observations of wind-fed Supergiant X-ray binaries that show significant superorbital variability. Their superorbital periods show a possible correlation with their binary orbits, where they were found to be on the order of 3-4 times the length of their orbital period. Dynamic power spectra and fractional root mean square analyses rms show that the amplitudes of modulation changes as a function of time, but no observed changes in the periods are found. NuSTAR and XRT observations show that their spectral shape hardens with increasing luminosity, which indicates that the superorbital modulation is linked to the mass accretion rate. I discuss different mechanisms that might drive the observed superorbital modulation.
##### Physics Colloquium

March 18, 2021
Zoom | Thursday, 3:30 pm

## Monica Olvera de la Cruz, Northwestern University

#### Control of Magnetoelastic Matter

Magnetic fields exert controllable forces that generate microscopic actuation and locomotion in soft materials with superparamagnetic or ferromagnetic components. I will describe the shape changes and materials parameters required to drive and direct matter including filaments, membranes and hydrogels with magnetic components using precessing magnetic fields.
##### JFI Special Zoom Colloquia

March 12, 2021
Zoom | Friday, 12:00 pm

## Melanie Mitchell, Santa Fe Institute

##### Physics Colloquium

March 11, 2021
Zoom | Thursday, 3:30 pm

## Active platelets

#### when light locally melts a liquid crystal

Come at noon.
Find out what's an active platelet at 12:15
##### MRSEC Baglunch

March 5, 2021
Zoom | Friday, 12:00 pm

## Peko Hosoi, MIT

##### Physics Colloquium

March 4, 2021
Zoom | Thursday, 3:30 pm

## How thick is your skin

#### ... and why?

How thick is your skin ... and why?
Come at noon. The skin exposé will start at 12:15
##### MRSEC Baglunch

February 26, 2021
Zoom | Friday, 12:00 pm

## Cora Dvorkin, Harvard

#### Discovering New Physics with Cosmological Data Sets

Measurements of the Cosmic Microwave Background and the large-scale structure of the universe have made it possible to determine with great precision the universe's inventory, as well as properties of its initial conditions. However, there are profound questions that remain unanswered.

Cosmological observations and galaxy dynamics seem to imply that 84% of all matter in the universe is composed of dark matter, which is not accounted for by the Standard Model of particles. The particle nature of dark matter is one of the most intriguing puzzles of our time.

The wealth of knowledge which is and will soon be available from cosmological surveys will reveal new information about our universe. I will discuss how we can use new and complementary data sets to identify new physics at different scales.
##### Physics Colloquium

February 25, 2021
Zoom | Thursday, 3:30 pm

## agenda-less baglunch

No speaker this week, but if you join, others will be there. At least, I will
##### MRSEC Baglunch

February 19, 2021
Zoom | Friday, 12:00 pm

## Phillip Phillips, UI Urbana-Champaign

##### Physics Colloquium

February 18, 2021
Zoom | Thursday, 3:30 pm

## from spinning particles to rotating fluids?

Toon in at noon to enjoy company

Last 'til quarter past for some misbehaving fluids
##### MRSEC Baglunch

February 12, 2021
Zoom | Friday, 12:00 pm

## winter.

#### fingers in ice. rays in coffee.

In the winter,
fingers form in the ice
while rays appear in your coffee

Come at noon to enjoy company

Stay at 12:15 for some more self-assembled structure in fluids
##### MRSEC Baglunch

February 5, 2021
Zoom | Friday, 12:00 pm

## Bozhi Tian, University of Chicago

#### Bioelectrical and Life-like Interfaces

Biological systems respond to and communicate through biophysical cues, such as electrical, thermal, mechanical, and topographical signals. The mission of the Tian lab is to discover new bioelectrical signaling processes in cells and tissues and, to that end, establish a new paradigm for bioelectronic medicine. We have employed a range of material synthesis and device design principles, revealed multiple signal transduction mechanisms at bioelectronic and biophotonic interfaces, and pushed the limits in organelle level biointerfaces. Since July 2018, our research has significantly expanded: A) My lab has extended our previous studies of optically-triggered and non-genetic neuromodulation to include cardiac and microbial modulation interfaces. B) Beyond silicon-based biomaterials, my lab has developed new synthesis strategies for silicon carbide-, carbon-, liquid metal- and mineral-based structures. We have demonstrated the utility of these structures in sensing or modulation biointerfaces. C) Using granular materials and hydrogels, we have developed tissue-like composites, studied their unique mechanical properties, and applied them in bioelectronics and robotics. D) My lab has established several new living materials systems wherein bacterial cells yield therapeutic or waste clearing effects. In this talk, I will discuss some of these latest advances in my lab, and present new materials and biological targets that could catalyze future ad
##### Chemistry

February 1, 2021
Zoom | Monday, 3:45 pm

## Beyoncé's law ""If you like it then you're sure to put a ring on it"

#### The pressure is on for viscous fingers

Come at noon to enjoy company

Stay at 12:15 for
Beyoncé's law ""If you like it then you're sure to put a ring on it"
The pressure is on for viscous fingers

...and we will like it, I very much believe.
##### MRSEC Baglunch

January 29, 2021
Zoom | Friday, 12:00 pm

## Gia Dvali, NYU/MPI

##### Physics Colloquium

January 28, 2021
Zoom | Thursday, 3:30 pm

## Alex Dickson, Michigan State

#### Improving drug discovery through molecular simulation

Despite decades of advances in computing, genomics and structural biology, we are still unable to predict which candidates will be successful during drug development. This greatly increases the cost of bringing a new drug to market, which contributes to the rising costs of health care. The Dickson Lab at MSU works to develop new computational methodologies for modeling molecular interactions that are relevant to drug activity. This includes novel algorithms to simulate ligand unbinding events that typically occur on timescales that are millions of times longer than typical molecular dynamics simulations. From these trajectories we can identify and analyze the transition states of the ligand release pathway that determine the kinetics of ligand binding and release, which are necessary to model drug action in the body. The Dickson Lab is also developing new simulation approaches for efficient calculation of the free energy along the binding pathway using non-equilibrium pulling trajectories and the Jarzynski equality. Finally, this talk will present a general scheme to predict molecular properties such as solubility and the partition coefficient that can be combined with (un)binding rates as inputs to holistic models of drug action in the body. Together these developments aim to improve our ability to predict successes and failures early in the drug development pipeline.
##### Chemistry

January 25, 2021
Zoom | Monday, 3:45 pm

## Michael Levin, University of Chicago

##### Physics Colloquium

January 21, 2021
Zoom | Thursday, 3:30 pm

## Karin Oberg, Harvard University

#### Astrochemistry and Compositions of Planetary Systems

The origins of planets and the origins of planetary compositions are intimately linked to the chemical environments within which planets assemble, i.e. to the chemistry of planet-forming disks. The arrival of ALMA has provided observational access to disk chemistry, revealing abundant organic molecules, snowlines, enhanced C/O ratios, and curious chemical gradients and sub-structures across the planet- and comet-forming zones. The most recent development is the execution of the ALMA Large Program MAPS (Molecules with ALMA on Planet-forming Scales), which has enabled us to zoom in on disk chemical structures at scales of 10–30~au. In parallel to these observational developments, astrochemical models and laboratory experiments are providing new clues on what chemistry is likely to occur in different disk environments. In this talk I will present highlights from the MAPS program, and discuss how these new observational data together with ongoing laboratory and theoretical efforts inform our understanding of the chemistry of planet formation, the chemical habitability of mature planetary systems, and the history of our own Solar System.
##### The Professor Gerhard L. Closs Lecture Series

January 19, 2021
Zoom | Tuesday, 3:45 pm

## Seasonal disease patterns point at a built-in annual clock in humans

At noon: come and kibbitz
At 12:15: Seasonal disease patterns point at a built-in annual clock in humans
##### MRSEC Baglunch

January 15, 2021
Zoom | Friday, 12:00 pm

## David Schuster, University of Chicago

##### Physics Colloquium

January 14, 2021
Zoom | Thursday, 3:30 pm

## Nuh Gedik, Massachusetts Institute of Technology

##### Molecular Engineering

January 13, 2021
Zoom | Wednesday, 11:00 am

## Membranes to Avalanches

#### trying to turn critical phenomena into a useful tool

At noon: harmless banter
At 12:15: the heart of the matter: Membranes to Avalanches: trying to turn critical phenomena into a useful tool
##### MRSEC Baglunch

January 8, 2021
Zoom | Friday, 12:00 pm

## Kyogo Kawaguchi, Riken Hakubi Research Team

#### Chiral Dynamics and Boundary Wave of Active Nematic Neural Progenitors

Biomolecules are chiral in nature, and can build up to make large and consistent left-right asymmetric patterns like our body. The general mechanism of how the dynamics of biomatters can couple with their own inherent chirality to produce macroscopic patterns is yet to be elucidated. We have recently found that neural progenitor cells (NPCs), an example system of active liquid crystal, exhibit large-scale chiral patterns as well as chiral flow at the edge of the culture substrate. As predicted by a hydrodynamic theory analogous to a quantum-mechanical equation, we observe an edge-localized unidirectional mode in the spectrum of the cell density that corresponds to the topological Kelvin wave. In this talk, I will briefly explain the background on the connection between active matter physics and biology, then introduce our experimental system [1], and finally discuss some recent results[2].
##### Special Virtual Seminar

December 18, 2020
Zoom | Friday, 4:00 pm

## degrees of freedom in mechanical systems

#### some matter, some don't

the [MRSEC-baglunch] listserve at this link:
https://lists.uchicago.edu/web/subscribe/mrsec-baglunch
you can opt out, search prior titles, receive summaries, etc. at your pleasure.
##### MRSEC Baglunch

December 18, 2020
Zoom | Friday, 12:00 pm

## Alexander Seidel, Washington University in St. Louis

December 14, 2020
Zoom | Monday, 1:30 pm

## Tristan Hubsch, Howard University

#### The Dark Side of String Theory

A closer reexamination of a family of models with a 3+1-dimensional de Sitter spacetime obtained in the standard low-energy limit of string theory reveals a host of novel features: On the phenomenological side, they predict several types of dark energy and dark matter, including a cosmological constant consistent with observations of the accelerated expansion of the Universe. These stem from cosmologically broken supersymmetry, the inherent strong coupling of these models, and the ensuing involvement of additional, non-commutative, phase-space-like stringy degrees of freedom. The inclusion of these, hitherto ignored degrees of freedom also implies a natural seesaw-like solution to the hierarchy problem.
##### Physics Colloquium

December 10, 2020
Zoom | Thursday, 3:30 pm

## David Awschalom, Uchicago

#### Q-NEXT: Engineering Entanglement for Computation, Communication and Sensing

As one of the five national DOE Quantum Information Science Research Centers, Q-NEXT brings together researchers in national laboratories, academia and the private sector to create an innovation ecosystem that enables the translation of discovery science into technologies. Led by Argonne National Laboratory, Q-NEXT includes three national laboratories, nine universities and ten of the U.S.’s leading quantum technology companies. The Center focuses on how to reliably control, store, and transmit quantum information with entanglement at distances from microns to kilometers. Addressing this challenge requires developing novel quantum materials and integrating them into devices and systems, developing new classes of ultra-precise sensors, and overcoming losses that occur when quantum information is communicated over long distances. The Center will also develop simulation and characterization tools that we can apply to these quantum systems.
##### EFI Colloqium

December 7, 2020
Zoom | Monday, 3:30 pm

#### Quantum smectic gauge theory

I will discuss a gauge theory formulation of a two-dimensional quantum smectic and its relatives, motivated by their realizations in correlated quantum matter. The description gives a unified treatment of phonons and topological defects, respectively encoded in a pair of coupled gauge fields and corresponding charges. The charges exhibit subdimensional constrained quantum dynamics and anomalously slow highly anisotropic diffusion of disclinations inside a smectic. This approach gives a transparent description of a multi-stage quantum melting transition of a two-dimensional commensurate crystal (through an incommensurate crystal -- a supersolid) into a quantum smectic, that subsequently melts into a quantum nematic and isotropic superfluids, all in terms of a sequence of Higgs transitions.

December 7, 2020
Zoom | Monday, 1:30 pm

## Michael Ramsey-Musolf, UMass Amherst

#### Shattering the Lavender Ceiling: A Gay Physicist's Perspective

Science advances most effectively when the scientific community embraces and supports scientists from all backgrounds and identities. In this talk, I focus on the particular challenges to full inclusion in the scientific enterprise faced by LGBTQ physicists – the “lavender ceiling”. I will share insights from my own experience as an out gay theoretical physicist and from a recent American Physical Society climate study. I will also highlight some “best practices” that a physics department may adopt to engender a more inclusive climate for sexual and gender minorities.
##### Physics Colloquium

December 3, 2020
Zoom | Thursday, 3:30 pm

## Michael Ramsey-Musolf, UMass Amherst

##### Theory Seminar

December 2, 2020
Zoom | Wednesday, 1:30 pm

## Brian Swingle, University of Maryland

November 30, 2020
Zoom | Monday, 1:30 pm

## Laura Gagliardi, The University of Chicago & Hong Jiang, Peking University

##### PKU-UChicago Joint Lecture Series: Symposium on Theoretical Chemistry

November 23, 2020
Zoom | Monday, 7:00 pm

## Coherent Quantum Sensors

#### Probing biological systems at a single-molecule level

This week's zoom baglunch will begin as usual with a bit of harmless banter at noon. Please bring banter material!

then at 12:15 comes
Coherent Quantum Sensors: Probing biological systems at a single-molecule level

the [MRSEC-baglunch] listserve at this link:
https://lists.uchicago.edu/web/subscribe/mrsec-baglunch
you can opt out, search prior titles, receive summaries, etc. at your pleasure.
##### MRSEC Baglunch

November 20, 2020
Zoom | Friday, 12:00 pm

## Jeff Martoff, Temple University

#### The HUNTER Sterile Neutrino Search

The HUNTER experiment (Heavy Unseen Neutrinos from Total Energy-momentum Reconstruction) is a search for sterile neutrinos with masses in the 20-280 keV range. The neutrino missing mass will be reconstructed from 131-Cs electron capture decays occurring in a magneto-optically trapped sample of atoms. Reaction-microscope spectrometers will be used to detect all charged decay products with high solid angle efficiency, and a position- and energy-sensitive scintillator array detects x-rays, each with sufficient resolution to reconstruct the neutrino missing mass. The experiment requires EUHV pressure, very uniform ion extraction electric field and electron confinement magnetic field, large solid angle for x-ray detection, and precision in-situ alignment. Procurement of major components of HUNTER is well underway, implementing some innovative solutions to these requirements.

We thank the W. M. Keck Foundation, the Gordon and Betty Moore Foundation, and our respective universities for financial support of HUNTER.

Jeff Martoff, Eric R. Hudson, Paul Hamilton, Peter F. Smith, Christian Schneider, Andrew L. Renshaw, Peter D. Meyers, Basu R. Lamichhane, Xunzhen Yu, Eddie Chang, Frank C. Malatino (Temple University, UCLA, University of Houston, Princeton University, Grand Valley State University)

##### Physics Colloquium

November 19, 2020
Zoom | Thursday, 3:30 pm

## Tim Lyons, UC Riverside

#### Constraining prebiotic chemistry through a better understanding of Earth’s earliest environments

Any search for present or past life beyond Earth should consider the initial processes and related environmental controls that might have led to its start. As on Earth, such an understanding lies well beyond how simple organic molecules become the more complex biomolecules of life, because it must also include the key environmental factors that permitted, modulated, and most critically facilitated the prebiotic pathways to life’s emergence. Moreover, we ask how habitability, defined in part by the presence of liquid water, was sustained so that life could persist and evolve to the point of shaping its own environment. Researchers have successfully explored many chapters of Earth’s coevolving environments and biosphere spanning the last few billion years through lenses of sophisticated analytical and computational techniques, and the findings have profoundly impacted the search for life beyond Earth. Yet life’s very beginnings during the first hundreds of millions of years of our planet’s history remain largely unknown. This talk will center on one key point: that the earliest steps on the path to life’s emergence on Earth were tied intimately to the evolving chemical and physical conditions of our earliest environments. Yet, a rigorous interdisciplinary understanding of that relationship has not been explored adequately. Studies of the emergence of life require a mix that expands the traditional platform of prebiotic chemistry to include geochemists, atmospheric chemists, geologists and geophysicists, and planetary scientists, among others. This talk will outline the emerging targets and strategies in this pursuit, including efforts within the framework of NASA’s Prebiotic Chemistry and Early Earth Environments Research Coordination Network.
##### Origins of Life Speaker Series

November 19, 2020
Zoom | Thursday, 1:30 pm

## Andreas Crivellin, University of Zurich

#### Discovering New Physics with Flavour

Discovering New Physics with Flavour, Andreas Crivellin, University of Zurich

Within recent year, flavour and low-energy precision experiments have accumulated intriguing hints for the violation of lepton flavour universality (LFU), i.e. physics beyond the Standard Model which interacts differently with electrons, muons and tau leptons. In particular, the long-standing anomaly in the anomalous magnetic moment (AMM) of the muon is now accompanied tensions in semi-leptonic B decays (most pronounced in b->smumu data) as well as its sibling, the AMM of the electron. Furthermore, also the hint for a (apparent) violation of first-row CKM unitarity can be viewed as a sign for LFU violation.

After reviewing the current experimental and theoretical status, I discuss how these anomalies can be (individually) explained in terms of NP. Furthermore, combining the explanations of different anomalies, one can predict interesting correlations with, and signatures in, other flavour observables. Furthermore, the flavour anomalies can be used to construct a compelling physics case for future colliders such as the FCC-ee and the FCC-hh.
##### Theory Seminar

November 18, 2020
Zoom | Wednesday, 1:30 pm

## Sheng Xu, University of California-San Diego

#### New Materials and Devices for Soft Electronics

Abstract: Soft electronic devices that seamlessly integrate with the human body represent an essential trend for future consumer electronics and mobile healthcare. Combined strategies of advanced microfabrication and materials design allow the integration of various components and devices on a soft platform, resulting in functional systems with minimal constraints on the human body. In this presentation, I will demonstrate the first of its kind a multilayered stretchable multichannel patch that can sense a collection of signals from the human skin in a wireless mode. Additionally, existing wearable electronic devices are limited to sensing signals on the skin surface. I will show a stretchable ultrasonic patch that adds a new third dimension to the detection range of existing soft electronics. Ultrasound waves can penetrate the skin and noninvasively capture dynamic events in deep tissues, such as blood pressure and blood flow waveforms in central arteries and veins. For the power source, I will demonstrate a protocol for growing large area single-crystal hybrid halide perovskites for high performance flexible solar cells. This soft platform holds profound implications for a wide range of applications in personal electronics, sports medicine, defense, and clinical practices. Host: Bozhi Tian via email at btian@uchicago.edu. If you need assistance or more information please contact Brenda Thomas at bthomas@uchicago.edu. ZOOM MEETING INFORMATION WILL BE SENT VIA EMAIL ANNOUNCEMENT.
##### The Tuesday JFI Seminar

November 17, 2020
Zoom | Tuesday, 3:45 pm

## Suriyanarayanan Vaikuntanathan, The University of Chicago & Jian Liu, Peking University

##### PKU-UChicago Joint Lecture Series: Symposium on Theoretical Chemistry

November 16, 2020
Zoom | Monday, 7:00 pm

## Chibueze Amanchukwu and Chong Liu

#### two talks by MRSEC seed leaders

This Friday will be the first of four sessions introducing new MRSEC members and their seed projects.
The goal is to encourage collaboration between these new projects and us all. Each speaker will give a brief introduction aimed at launching a discussion. We'll start at 12:00 for we can all come and say hi before the talks. Feel free to eat food! Then at 12:15 we'll have a seed leader discuss their seed. The second leader will take over at 12:45. We'll finish the meeting at 13:15 or so, but will keep the zoom session open for more talk and questions.
##### MRSEC Baglunch

November 13, 2020
Zoom | Friday, 12:00 pm

## Nigel Goldenfeld, University of Illinois Urbana Champaign

#### The life and death of turbulence

Turbulence is the last great unsolved problem of classical physics. But there is no consensus on what it would mean to actually solve this problem. In this colloquium, I propose that turbulence is most fruitfully regarded as a problem in non-equilibrium statistical mechanics, and will show that this perspective explains turbulent drag behavior measured over 80 years, and makes predictions that have been experimentally tested in 2D turbulent soap films. I will also explain how this perspective is useful in understanding the laminar-turbulence transition, establishing it as a non-equilibrium phase transition whose critical behavior has been predicted and tested experimentally. This work connects transitional turbulence with statistical mechanics and renormalization group theory, high energy hadron scattering, the statistics of extreme events, and even population biology.

Event Type
Colloquia and Lectures

NOV
12
##### Physics Colloquium

November 12, 2020
Zoom | Thursday, 3:30 pm

## John Sutherland, Cambridge

#### Origins of Life Systems Chemistry

By reconciling previously conflicting views about the origin of life – in which one or other cellular subsystem precedes, and then ‘invents’ the others – we suggested a new modus operandi for its study. Guided by this, we uncovered a cyanosulfidic protometabolism which uses UV light and the stoichiometric reducing power of hydrogen sulfide to convert hydrogen cyanide, and a couple of other prebiotic feedstock molecules which can be derived therefrom, into nucleic acid, peptide and lipid building blocks. We are now considering the transition of systems from the inanimate to the animate state through intermediate stages of partial ‘aliveness’, and recent progress in the elaboration of building blocks into larger (oligomeric) molecules and systems in this context will also be described.

##### Origins of Life Speaker Series

November 12, 2020
Zoom | Thursday, 1:30 pm

## Benjamin Lev, Stanford University

#### Topological Pumping of a 1D Dipolar Gas into Quantum Many-Body Scar States

Long-lived excited states of interacting quantum systems that retain quantum correlations and evade thermalization are of great fundamental interest. We have created novel nonthermal states in a bosonic 1D quantum gas of dysprosium by stabilizing a super-Tonks-Girardeau gas against collapse and thermalization with repulsive long-range dipolar interactions. Stiffness and energy-per-particle measurements show that the system is dynamically stable regardless of contact interaction strength. This enables us to cycle contact interactions from weakly to strongly repulsive, then strongly attractive, and finally weakly attractive. We show that this cycle is an energy-space topological pump (due to a quantum holonomy). Iterating this cycle offers an unexplored topological pumping method to create a hierarchy of increasingly excited prethermal states. Host: Jonathan Simon via email at simonjon@uchicago.edu. If you have any questions or may need assistance please contact Brenda Thomas at bthomas@Uchicago.edu. ZOOM MEETING INFORMATION WILL BE SENT VIA EMAIL ANNOUNCEMENT.
##### The Tuesday JFI Seminar

November 10, 2020
Zoom | Tuesday, 3:45 pm

## David A. Mazziotti, The University of Chicago & Chen Li, Peking University

##### PKU-UChicago Joint Lecture Series: Symposium on Theoretical Chemistry

November 9, 2020
Zoom | Monday, 7:00 pm

## Ehud Altman, Berkeley

November 9, 2020
Zoom | Monday, 1:30 pm

## Enectali Figueroa-Feliciano, Northwestern

#### Searching for Physics Beyond the Standard Model with Rockets and Nuclear Reactors

We know that the Standard Model of Particle Physics is not complete. Although extremely successful, the Standard Model does not account for the mass of neutrinos or the existence of dark matter, among other problems. Even though dark matter makes up 26% of the universe, we do not know what it is made of. At the same time, we don’t know why neutrinos have mass. One of the main mechanisms for neutrino mass predicts the existence of new particles called sterile neutrinos. If sterile neutrinos exist, some of them could make up the dark matter. Sterile neutrino dark matter could be detected through observations in space of X-rays produced in their decay into standard model particles. We detail a program to search for these dark matter signals in space using the Micro-X Rocket, a NASA-funded sounding rocket payload. Using the same detector technology, the Ricochet experiment will study neutrinos at a nuclear reactor through coherent elastic neutrino-nucleus scattering. Both of these experiments search for physics beyond the standard model in the neutrino sector.
##### Physics Colloquium

November 5, 2020
Zoom | Thursday, 3:30 pm

## Daniel Glavin, NASA Goddard Space Flight Center

#### Meteorite Delivery of Prebiotic Organics: An Inventory for the Origin of Life

Meteorites provide a record of the chemical processes that occurred in the early solar system before life began on Earth. The delivery of complex organic compounds by carbonaceous chondrites to the early Earth and other planetary bodies could have been an important source of prebiotic organic compounds required for the emergence of life. Of particular interest is the study of meteoritic amino acids and their enantiomeric compositions since these molecules are the monomers of proteins common to all life on Earth. The single chirality observed in biological molecules - left-handed amino acids and right-handed sugars - is a property important for molecular recognition processes and is thought to be a prerequisite for life. In contrast to biology, all known non-biological reactions result in equal mixtures of left- and right-handed (L = D) amino acids and sugars. Therefore, how the nearly exclusive production of one hand of such molecules arose from what were presumably equal mixtures of L and D molecules in a prebiotic world has been an area of intensive research. A predominance of left- over right-handed amino acids (up to ~60%) has been found in some meteorites, but how this large amino acid asymmetry came about remains unclear. This talk will discuss the possible chemical origins of amino acids and other prebiotic organic compounds in meteorites and the implications for the origin of homochirality in life on Earth and the search for chemical evidence of life elsewhere.
##### Origins of Life Speaker Series

November 5, 2020
Zoom | Thursday, 1:30 pm

## Laura Gagliardi and Sarah King

#### two talks by MRSEC seed leaders

This Friday will be the first of four sessions introducing new MRSEC members and their seed projects.
The goal is to encourage collaboration between these new projects and us all. Each speaker will give a brief introduction aimed at launching a discussion. We'll start at 12:00 for we can all come and say hi before the talks. Feel free to eat food! Then at 12:15 we'll have a seed leader discuss their seed. The second leader will take over at 12:45. We'll finish the meeting at 13:15 or so, but will keep the zoom session open for more talk and questions.
##### MRSEC Baglunch

November 5, 2020
Zoom | Thursday, 12:00 pm

##### Computations in Science

November 4, 2020
KPTC 206 | Wednesday, 12:15 pm

## Aaron Dinner, The University of Chicago & Luhua Lai, Peking University

##### PKU-UChicago Joint Lecture Series: Symposium on Theoretical Chemistry

November 2, 2020
Zoom | Monday, 7:00 pm

## Tomaz Prosen, University of Ljubljana

#### Exactly solved models of many-body quantum chaos

One should be amazed with an unreasonable effectiveness of random matrix theory to describe spectral fluctuations in simple non-integrable many-body systems, say one dimensional spin 1/2 chains with local interactions. I will discuss several models of Floquet (periodically driven) quantum spin chains, where the random matrix result for the spectral form factor can be derived or even rigorously proven. Several other nontrivial exactly solvable features of the presented models, such as dynamical correlations or entanglement dynamics, will be discussed.

November 2, 2020
Zoom | Monday, 1:30 pm

## Allison Squires and Sihong Wang

#### two talks by MRSEC seed leaders

This Friday will be the first of four sessions introducing new MRSEC members and their seed projects.
The goal is to encourage collaboration between these new projects and us all. Each speaker will give a brief introduction aimed at launching a discussion. We'll start at 12:00 for we can all come and say hi before the talks. Feel free to eat food! Then at 12:15 we'll have a seed leader discuss their seed. The second leader will take over at 12:45. We'll finish the meeting at 13:15 or so, but will keep the zoom session open for more talk and questions.
##### MRSEC Baglunch

October 30, 2020
Zoom | Friday, 12:00 pm

## Michael Murrell, MIT

#### The Non-Equilibrium Mechanics of Soft Interfaces

At small length-scales, capillary effects are significant, and thus the mechanics of soft material interfaces may be dominated by solid surface stresses and liquid surface tensions. The balance between surface and bulk properties is described by an elasto-capillary length-scale, in which equilibrium interfacial energies are constant. However, at small length-scales in biological materials, including living cells and tissues, interfacial energies are not constant, but are actively regulated and driven far from equilibrium. Thus, the balance between surface and bulk properties depends upon the distance from equilibrium, defining a novel material parameter, what we term “active” elasto-capillarity. Here, we model the adhesion and spreading (wetting) of living cell aggregates as ‘active droplets’, with a non-equilibrium surface energy that depends upon internal stress generated by the actomyosin cytoskeleton. Depend upon the extent of activity, the droplet may exhibit both surface stress and surface tension, and each may adapt to the mechanics of their surroundings. The impact of this activity-dependent adaptation challenges contemporary models of interfacial mechanics, including traditional and extensively used models of contact mechanics and wetting. Finally, we show the origin of adaptation is in the breaking of detailed balance at the molecular scale by stochastic binding in the actomyosin cytoskeleton.
##### Physics Colloquium

October 29, 2020
Zoom | Thursday, 3:30 pm

## Jenny Bergner, University of Chicago

#### Astronomical insights on the delivery of organic building blocks to new worlds

The viability of prebiotic chemistry on a nascent planet is dependent on the inventory of organic building blocks incorporated during the planet's formation, particularly the elements C,N,O,P,S. This raises the questions: how did Earth come to obtain its prebiotic precursors, and how commonly do other planets also inherit the ingredients for prebiotic chemistry? By studying the volatile/organic chemistry at play in the evolutionary progenitors of planetary systems (protostars and protoplanetary disks), we gain a valuable window into the initial chemical conditions of planet formation. This talk will discuss advances in characterizing the organic chemistry ongoing during the assembly of planetary systems, largely thanks to the unprecedented sensitivity and spatial resolution of the ALMA interferometer. Despite recent progress, we still cannot directly probe the volatile material relevant for terrestrial planet formation, and this discussion will highlight how complementary simulations and laboratory experiments have been critical for interpreting the observations. We will also discuss future avenues for progress, in particular the upcoming James Webb Space Telescope, which will directly probe the composition of icy material relevant for planet and planetesimal formation.
##### Origins of Life Speaker Series

October 29, 2020
Zoom | Thursday, 1:30 pm

## Giulia Galli, The University of Chicago & Zhirong Liu, Peking University

#### Quantum Simulations of Heterogeneous Materials on Classical and Near-term Quantum Computers & Ensemble-based Thermodynamics of the Fuzzy Binding between Intrinsically Disordered Proteins and Small Molecule Ligands: Principle and Application

Title:
Quantum Simulations of Heterogeneous Materials on Classical and Near-term Quantum Computers

Abstract:
In this talk Prof Galli will present strategies to predict and design materials for next generation technologies by combining theories based on quantum mechanics, and algorithms and codes running on high performance classical computers, and, in some cases, on near-term quantum computers. She will present examples of calculations addressing two outstanding challenges: designing sustainable materials to efficiently capture solar energy, and inventing materials to build radically novel sensors and computers, to move in earnest into the quantum information age.

Title:
Ensemble-based Thermodynamics of the Fuzzy Binding between Intrinsically Disordered Proteins and Small Molecule Ligands: Principle and Application

Abstract:
The “lock-and-key” model is the basis of molecular recognition concerning biological macromolecules and played an essential role in the long-term success of drug development. However, intrinsically disordered proteins (IDPs), which exist in an ensemble of rapidly changing conformations and exhibit almost unlimited structural heterogeneity, have brought challenge to the conventional paradigm. How is a key able to match locks with different shapes? More scientifically, how to properly access the binding affinity between a small molecule ligand and a conformational ensemble of proteins? In our work, we presented an ensemble-based thermodynamic framework to analyze the fuzzy ligand-IDPs interactions. It is shown that the apparent affinity acts in a way similar to the Jarzynski’s equality in nonequilibrium statistics. The oncoprotein c-Myc is adopted as an example to demonstrate the related properties, e.g., the distribution of conformation-ligand interaction free energy, the entropic contribution from the ensemble, the conformation shift under ligand binding, and how to control the error under a limited number of sampled conformations. In addition, we proposed a reinforcement learning algorithm for virtual screening upon IDPs, which greatly reduces the docking number while achieving both high screening accuracy and low performance loss.
##### PKU-UChicago Joint Lecture Series: Symposium on Theoretical Chemistry

October 26, 2020
Zoom | Monday, 8:00 pm

## Isreal Klich, University of Virginia

October 26, 2020
Zoom | Monday, 1:30 pm

## Steve Sibener

#### Active and Responsive Molecular and Polymer Films

This Friday will be the first of four sessions introducing new MRSEC members and their seed projects.
The goal is to encourage collaboration between these new projects and us all. Each speaker will give a brief introduction aimed at launching a discussion. We'll start at 12:00 for we can all come and say hi before the talks. Feel free to eat food! Then at 12:15 we'll have a seed leader discuss their seed. The second leader will take over at 12:45. We'll finish the meeting at 13:15 or so, but will keep the zoom session open for more talk and questions.

This Friday's talk is a new project by an established member and former Director, Steve Sibener. His title is
Active and Responsive Molecular and Polymer Film
##### MRSEC Baglunch

October 23, 2020
Zoom | Friday, 12:00 pm

## Andrea Ghez, UCLA

#### The Monster at the Heart of our Galaxy

Learn about new developments in the study of supermassive black holes. Through the capture and analysis of twenty years of high-resolution imaging, the UCLA Galactic Center Group has moved the case for a supermassive black hole at the center of our galaxy from a possibility to a certainty and provided the best evidence to date for the existence of these truly exotic objects. This was made possible with the first measurements of stellar orbits around a galactic nucleus. Further advances in state-of-the-art of high-resolution imaging technology on the world’s largest telescopes have greatly expanded the power of using stellar orbits to study black holes. Recent observations have revealed an environment around the black hole that is quite unexpected (young stars where there should be none; a lack of old stars where there should be many; and a puzzling new class of objects). Continued measurements of the motions of stars have solved many of the puzzles posed by these perplexing populations of stars. This work is providing insight into how black holes grow and the role that they play in regulating the growth of their host galaxies. Measurements this past year of stellar orbits at the Galactic Center have provided new insight on how gravity works near a supermassive hole, a new and unexplored regime for this fundamental force of nature.
##### 2020 Maria Goeppert-Mayer Lecture

October 22, 2020
Zoom | Thursday, 3:30 pm

## Timothy Cohen, University of Oregon

#### Soft de Sitter Effective Theory

In this talk, I will introduce the Soft de Sitter Effective Theory (SdSET), whose purpose is to model the long wavelength dynamics of quantum fluctuations beyond the horizon. After providing some conceptual and technical issues that motivate the need for a new EFT approach, I will explain how we identify the propagating low energy degrees of freedom, along with their scaling under a power counting scheme and their transformation properties under the symmetries that persist to the IR. I will sketch how to derive the SdSET action, and will argue that it can be expressed as an expansion in local operators, augmented by stochastic initial conditions. Finally, I will show how this framework can be applied to a number of physically interesting problems: massive scalar fields in dS, light scalar fields and stochastic inflation, conservation of the inflationary adiabatic modes, and the phase transition to eternal inflation.
##### Theory Seminar

October 22, 2020
Zoom | Thursday, 1:30 pm

## Sara Walker, Arizona State

#### Inferring the 'Laws of Life' at a Planetary Scale

In 1943, Erwin Schrodinger famously delivered a set of lectures at the Dublin Institute for Advanced Studies aiming to tackle the question “What is Life?” from the first-principles approach of a theoretical physicist. Over 70 years later, we’ve still made little headway in coming up with a general theory for what life is. While many definitions for life do exist, these are primarily descriptive, not predictive, and they have so far proved insufficient to explain the origins of life from non-living matter, or to provide rigorous constraints on what properties are universal to all life, even that on other worlds. Yet, as NASA and other space agencies are setting sights on life detection as a goal of upcoming robotic missions and space observatories, more rigorous understanding of the universal properties of living matter are becoming increasingly vital to uncover. This talk will discuss new approaches to understanding what universal principles might underlie living matter and how to generate it, based on studying biochemical networks on Earth from the scale of individual organisms to the planetary scale.
##### Origins of Life Speaker Series

October 22, 2020
Zoom | Thursday, 1:30 pm

## Prof. Jan Engelbrecht, Boston College

#### Group Theoretic and Geometric Implications for Kuramoto Oscillator Networks

In Kuramoto Oscillator Network Models, an underlying symmetry constrains the system dynamics to low-dimensional manifolds that can be characterized through the action of the 3D Möbius group. These Möbius transformations are the isometries of the Poincaré Disk. We explore the consequences of this hyperbolic geometry on oscillator dynamics, both for models with populations of N distinct identical oscillators or a continuum of identical oscillators. In the latter case we systematically extend the analysis off the famous Ott-Antonsen manifold of Poisson densities, and use a simple geometric argument to prove that the OA manifold is not attracting. Host: Peter Littlewood, littlewood@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at bthomas@uchicago.edu.
##### JFI Special Seminar

October 21, 2020
Zoom | Wednesday, 2:00 pm

## Gregory Voth, The University of Chicago & Yiqin Gao, Peking University

##### PKU-UChicago Joint Lecture Series: Symposium on Theoretical Chemistry

October 19, 2020
Zoom | Monday, 8:00 pm

## Ryan Thorngren, Harvard University

October 19, 2020
Zoom | Monday, 1:30 pm

## Gold nanorods reveal biomembrane mechanics

Dynamics and rheology of soft membrane: Probing lipid bilayer and plasma membrane mechanics using gold nanorod.

Perhaps you'd just like to join us at noon for conversation and a photo or joke.
Then again, you could join us when the gold nanorods take the stage
##### MRSEC Baglunch

October 16, 2020
Zoom | Friday, 12:00 pm

## Juan Maldacena, Princeton IAS

#### The entropy of Hawking radiation

We will discuss how to compute the entropy of Hawking radiation. The naive computation gives rise to an information problem. We will discuss a more recent computation which gives an answer that is in agreement with unitarity.
##### Physics Colloquium

October 15, 2020
Zoom | Thursday, 3:30 pm

## Anna Wang, University of New South Wales, Syndey

#### Hierarchical self-assembly of model primitive cells

This seminar will give an overview of how concepts from colloidal science and self-assembly can contribute to our understanding of how life originated from simple molecules. As a case study, the discussion will cover one process thought to be extremely favourable for the emergence of life: the ability for primitive cells to form networks and adhere, leading to robust communities that can share nutrients and genetic advantages. We first self-assemble solutions of giant unilamellar vesicles using fatty acids to use as a model system. The membranes are highly dynamic compared to phospholipid membranes, leading to interesting outcomes in self-assembly. The membranes also readily encapsulate RNA, and can store elastic energy. We will then discuss how the same membranes can also self-assemble into networks ranging from pairs to three-dimensional rafts. At first, the ability for the membranes to adhere appears confounding: like-charged membranes typically repel in the absence of fusogens or adhesives. We find that the observed aggregation can also be attributed to the dynamic properties of the bilayer system.
##### Origins of Life Speaker Series

October 15, 2020
Zoom | Thursday, 1:30 pm

## Sabetta Matsumoto, Georgia Institute of Technology

##### Computations in Science

October 14, 2020
KPTC 206 | Wednesday, 12:15 pm

## Harry Atwater - CALTECH

#### New Directions for Energy from Sunlight

The recent rapid, global growth of solar energy has expanded the science frontier in this area towards highly efficient direct artificial photosynthesis of energy-dense chemicals, fuels and materials from sunlight, water and carbon dioxide, with interest focused on hydrogen and products from reduction of carbon dioxide. Solar fuels generators are photoactive electrochemical systems with the additional science challenges of achieving high energy conversion efficiency, catalytic selectivity, and long-term component durability. This has motivated an accelerated discovery initiative, combining theory and experiment, to seek and find new photocatalyst and electrocatalyst materials, as well as multi-physics modeling to design prototype solar fuels generators Recently design of photoelectrochemical systems with semiconductors coupled to water oxidation and reduction catalysts have enabled solar-to-hydrogen generation with >19% efficiency and solar-driven CO2 to CO with similar efficiency. Solar-driven reduction of carbon dioxide to valuable products such as liquid fuels presents a particular challenge for selectivity in catalysis and I will describe new mechanisms for catalytic selectivity that combine heterogeneous and molecular catalysts, as well as approaches to use the optically excited states generated by light itself to create new catalytic pathways for CO2 reduction. Host: Christopher Melnychuk at cmelnychuk@uchicago.edu. For any other assistance please contact Brenda Thomas at bthomas@uchicago.edu. ZOOM MEETING INFORMATION WILL BE SENT VIA EMAIL ANNOUNCEMENT.
##### The Tuesday JFI Seminar

October 13, 2020
Zoom | Tuesday, 3:45 pm

## Julian Sonner , University of Geneva

October 12, 2020
Zoom | Monday, 1:30 pm

## MRSEC Rising Stars in Soft and Biological Matter Symposium

Please join us for a special symposium on October 8th and 9th highlighting fifteen early-career researchers working in the area of soft and biological matter, who also actively promote diversity in material science. The speakers come from backgrounds in Chemistry, Engineering, Physics and Biology.

https://mrsec.uchicago.edu/education/for-our-research-community/rising-stars-in-soft-and-biological-matter/

The schedule can be found here, with sessions starting at 11 AM CT both days. In addition to individual presentations, the speakers will collectively lead a discussion on future directions of the field at the end of the symposium. This should be a fun event!
##### MRSEC Symposium

October 9, 2020
Zoom | Friday, 11:00 am

## Henriette Elvang, University of Chicago

##### Physics Colloquium

October 8, 2020
Zoom | Thursday, 3:30 pm

## Jack Szostak, Harvard

#### The emergence of RNA from prebiotic mixtures of nucleotides

The first genetic polymers may have been nucleic acids with significant heterogeneity in the chemistry of their nucleobases, sugar components, and backbone connectivity. I will describe our ongoing efforts to explore the chemistry, structure and properties of potentially prebiotic versions of RNA, with particular emphasis on the effects of such variations on the process of nonenzymatic RNA replication. Our findings suggest a model for the transition from early heterogeneous nucleic acids to a more homogeneous form that is closer to modern RNA.
##### Origins of Life Speaker Series

October 8, 2020
Zoom | Thursday, 1:30 pm

## MRSEC Rising Stars in Soft and Biological Matter Symposium

Please join us for a special symposium on October 8th and 9th highlighting fifteen early-career researchers working in the area of soft and biological matter, who also actively promote diversity in material science. The speakers come from backgrounds in Chemistry, Engineering, Physics and Biology.

https://mrsec.uchicago.edu/education/for-our-research-community/rising-stars-in-soft-and-biological-matter/

The schedule can be found here, with sessions starting at 11 AM CT both days. In addition to individual presentations, the speakers will collectively lead a discussion on future directions of the field at the end of the symposium. This should be a fun event!
##### MRSEC Symposium

October 8, 2020
Zoom | Thursday, 11:00 am

## Michael Geller, Tel Aviv University

##### Theory Seminar

October 7, 2020
Zoom | Wednesday, 1:30 pm

## Alec Wodtke, Max Planck Institute for Biophysical Chemistry & Germany Institute for Physical Chemistry University of Göttingen

#### Experiments on Vibrational Energy Pooling and Transport in Condensed Phases Using a MID-IR Superconducting Nanowire Single Photon Detector

Superconducting nanowire single-photon detectors (SNSPDs) provide sufficient sensitivity to enable laser induced fluorescence (LIF) experiments in the mid-infrared, an exciting technical development for physical chemistry given the importance of vibrational spectroscopy to molecular science. In this talk, I will describe how an SNSPD works and how to use it. I will also present results of experiments on the vibrational dynamics of monolayers and multilayers of solid CO adsorbed at the surface of a NaCl crystal, to show the capabilities of time-resolved infrared LIF spectroscopy and provide observations of astonishing phenomena arising from dipole-dipole coupling between molecules. Host: Steven J. Sibener via email at sibener@uchicago.edu or phone: 773-702-7193. If other assistance is needed please contact Brenda Thomas at bthomas@uchicago.
##### The 1st Tuesday JFI Colloquium

October 6, 2020
Zoom | Tuesday, 12:00 pm

## Simon Caron-Huot, McGill

October 5, 2020
Zoom | Monday, 1:30 pm

## Jonathan Simon, University of Chicago

#### When Photons Self-Organized: Mott Insulators and Laughlin States of Light

In this talk I will describe the first materials composed of self-organized, strongly-interacting photons. These are (1) a Laughlin molecule of optical photons, and (2) a Mott insulator of microwave photons. The challenge of using light to make and probe these materials will teach us what each of these quantum few-body states is, and because we must engineer the photons to realize each necessary ingredient from the ground up, the materials will be distilled to their bare essentials. I will conclude with prospects to push these ideas even further, from synthetic wormholes for light to optical/mm-wave inter-converters.
##### Physics Colloquium

October 1, 2020
Zoom | Thursday, 3:30 pm

## Mark Van Raamsdonk, University of British Columbia

September 28, 2020
Zoom | Monday, 1:30 pm

## Hyperelastic, viscoelastic and auxetic robots

This week's zoom baglunch will begin as usual with a bit of harmless banter at noon. Please bring banter material!

then at 12:15 comes a new direction at the materials-robotics interface: Hyperelastic, viscoelastic and auxetic robots.
##### MRSEC Baglunch

September 25, 2020
Zoom | Friday, 12:00 pm

## Abigail Vieregg

##### Physics Colloquium

September 24, 2020
Zoom | Thursday, 3:30 pm

## Hong Liu, MIT

September 21, 2020
Zoom | Monday, 1:30 pm

## When drying sculpts the growth of soft labyrinths

Be there to warm up the speaker at noon
Be there to be warmed up by the speaker at 12:15
##### MRSEC Baglunch

September 18, 2020
Zoom | Friday, 12:00 pm

## Alex Maloney, McGill

#### Gravity from Averaging CFTs

I will explore the idea that certain theories of gravity in Anti-de
Sitter space are dual to an average over an ensemble of quantum
theories, rather than to a specific quantum theory. I will describe
an average over Narain’s family of two-dimensional conformal field
theories which describe free bosons on a torus, and compute the
partition function using the Siegel-Weil formula. The result takes
the form of a sum over geometries as one would expect in a theory of
gravity. But the gravitational theory looks more like a Chern-Simons
theory than like Einstein gravity.

September 14, 2020
Zoom | Monday, 1:30 pm

## Actin bundling

#### predictable crosslinked structure from nonequilibrium fast growth

Actin bundling: predictable crosslinked structure from nonequilibrium fast growth.

Saunter in to https://uchicago.zoom.us/j/924683431
around noon to see who is on hand.
12:15 is the time for actin'
##### MRSEC Baglunch

September 11, 2020
Zoom | Friday, 12:00 pm

## Elmer Guardado Sanchez , Princeton

#### Novel Systems for the Study of Out of Equilibrium Dynamics with a Fermion Quantum Gas Microscope

Ultracold gases in optical lattices provide an ideal platform to study the quantum many-boy thermalization of systems in and out of equilibrium. In our group, we use a Quantum Fermion Microscope to directly measure the density configurations of our system with single-site resolution. In this talk, I will describe the realization of two systems that have been proposed to exhibit non-ergodic behavior. First I will talk about our work studying the late-time effective hydrodynamics of a Fermi-Hubbard system subject to an external linear potential (a tilt''). The tilt couples mass transport to local heating through energy conservation. Due to this coupling the system quickly heats up to near infinite temperature in the lowest band of the lattice. We study the high-temperature transport and thermalization in our system as a function of tilt strength and find that the associated decay time crosses over as the tilt strength is increased from characteristically diffusive to subdiffusive with quartic scaling. For strong tilts, the subdiffusive transport rate is set by a thermal diffusivity, which we are thus able to measure as a function of tilt in this regime. Next I will talk about our recent successful implementation of Rydberg dressing of lithium-6 in an optical lattice using single photon excitation at 230 nm. We use Ramsey interferometry to measure the interactions between the dressed atoms and study the lifetime of the Rydberg-dressed gas. The Rydberg-dressed spin-polarized system realizes a t-V model with isotropic interactions and hopping along one lattice axis. We probe the early-time quench dynamics of an initial charge density wave profile and observe a clear effect of the interactions on the dynamics. The light mass of lithium-6 facilitates exiting the frozen gas regime while the fermionic nature of the species opens the door to new avenues in the quantum simulation of Hamiltonians with long-range interactions.
##### JFI Virtual Special Seminar

September 9, 2020
Zoom | Wednesday, 2:30 pm

## Soft magnets and rigid oil

#### Getting the magnetoelastic bends

Follow the link at 11:45am this friday (the same link as usual) to hang out for a few minutes.
For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch

and then ... things will be revealed
##### MRSEC Baglunch

September 4, 2020
Zoom | Friday, 11:45 am

## less is less

You've heard of the maxim "less is more". That can be true but it's always true that
less is less.
For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

August 21, 2020
Zoom | Friday, 12:00 pm

## nonreciprocal forces

#### in optically assembled nanomaterials

at noon this friday (the same link as usual) to hang out for a few minutes and then discuss

Emergence of nonreciprocal interactions and phase transitions in optically assembled nanomaterials

starting at 12:15.

Bring a cool image or an off-beat question if you can.
For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

August 14, 2020
Zoom | Friday, 12:00 pm

## On the rigidity of replicated disorder

Friday noon is the time to zoom

Bring a joke or a video link or just come and see who is there.
What is your reaction to this preview of a virtual poster session?
You can look at a potential lounge room here:
https://hubs.mozilla.com/WYtg58G/jfi-test-room/

The aforementioned discussion on rigidity will begin around 12:15.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

July 24, 2020
Zoom | Friday, 12:00 pm

## Spinning Stingrays

#### How to harvest angular momentum out of thin air

Come for the chatter at noon
Stay for the stingrays at 12:15
For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

July 17, 2020
Zoom | Friday, 12:00 pm

## laid back baglunch

No luck finding speakers this time. Come if you have good zoom tips or rumors or questions
My question: when zoom communication grinds to a halt, what are the leading causes and possible cures?
When you would normally be explaining something at the blackboard, what do you do on zoom?

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

July 10, 2020
Zoom | Friday, 12:00 pm

## Juan Collar

#### New directions in coherent elastic neutrino-nucleus scattering

##### Physics Colloquium

July 2, 2020
Zoom | Thursday, 3:30 pm

## The Fuzzy Nanoparticle, the Fuzz, and the Water Slab

These three will meet with us via Zoom Friday at noon.

THey won't start their act until 12:15.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglu
##### MRSEC Baglunch

June 26, 2020
Zoom | Friday, 12:00 pm

## The family that zooms together blooms together

#### ... well maybe

We can talk about the one-electron accelerator from the colloquium. They're having a naming contest : ). I think the electron lasts long enough in there to think up a name. My nomination: Atto boy.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglu
##### MRSEC Baglunch

June 19, 2020
Zoom | Friday, 12:00 pm

## Sergei Nagaitsev

#### Grand challenges in Accelerator and Beam Physics

##### Physics Colloquium

June 18, 2020
Zoom | Thursday, 3:30 pm

## Michael Aizenman, Princeton

June 15, 2020
Zoom | Monday, 1:30 pm

## What does happen when flopping particles talk to each other?

Tune in Friday at noon to find out.
As usual, the revelations only come at 12:15, after we've shot the breeze a little bit.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

June 12, 2020
Zoom | Friday, 12:00 pm

## Washington (Wati) Taylor

##### Theory Seminar

June 10, 2020
Zoom | Wednesday, 1:30 pm

## Ki-Seok Kim, POSTECH Korea

##### Theory Seminar

June 8, 2020
Zoom | Monday, 1:30 pm

## slow day at the baglunch

Please join is if you like. Bring thoughts, pictures, links, jokes, etc.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

June 5, 2020
Zoom | Friday, 12:00 pm

## Carlos Wagner

#### Open Questions in Particle Physics

The Standard Model of Particle Physics is perhaps the most successful theory developed in the history of mankind. It explains a large diversity of physical phenomena, from what holds atoms and nuclei together, to the accurate prediction of the transformation (decay) of heavy particles into lighter ones, and of observables that have been measured with a precision of more than a part in a billion. Moreover, the discovery of the Higgs confirms the Standard Model explanation of the origin of the mass of elementary particles. This amazing theory, however, leaves many open questions. The most puzzling feature is that the Standard Model could have in principle answered most of them, but missed its chance to do so. I will discuss these missed opportunities, thereby describing the properties of this beautiful but complex theory. I will also briefly present the paths we have taken to solve these mysteries of nature by going beyond the Standard Model description.
##### Physics Colloquium

June 4, 2020
Zoom | Thursday, 3:30 pm

## K. Dane Wittrup, MIT

##### Molecular Engineering

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

## Luping Yu, University of Chicago

#### New Ladder Molecules and their Electric and Optical properties

##### Chemistry

June 1, 2020
Zoom | Monday, 3:45 pm

## Gabriel Cuomo, EPFL

June 1, 2020
Zoom | Monday, 1:30 pm

## how molecular motors could make a droplet twirl

Doors open at noon for foolery

Main event at 12:15

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

May 29, 2020
Zoom | Friday, 12:00 pm

## Dmitri Talapini, University of Chicago

#### New chemistry of low-dimensional materials

##### Chemistry

May 26, 2020
Zoom | Tuesday, 3:45 pm

## Deadbeats in the actin chain gang

Fopic of the week:
Deadbeats in the actin chain gang

People trickle in around noon to exchange well wishes and news. Some bring jokes, videos....

An organized discussion begins at 12:15

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

May 22, 2020
Zoom | Friday, 12:00 pm

## Peter Littlewood and Vincenzo Vitelli

#### Dynamical phase transitions at many-body exceptional points

Spontaneous synchronization is at the core of many natural phenomena. Your heartbeat is maintained because cells contract in a synchronous wave; some bird species synchronize their motion into flocks; quantum synchronization is responsible for laser action and superconductivity. The transition to synchrony, or between states of different patterns of synchrony, is a dynamical phase transition that has much in common with conventional phase transitions of state – for example solid to liquid, or magnetism – but the striking feature of driven dynamical systems is that the components are “active”. Consequently quantum systems with dissipation and decay are described by non-Hermitian Hamiltonians, and active matter can abandon Newton’s third law and have non-reciprocal interactions. This substantially changes the character of many-degree-of-freedom dynamical phase transitions, and the critical phenomena in their vicinity, since the critical point is an “exceptional point” where eigenvalues coalesce.

We will illustrate this in two very different systems – a Bose-Einstein condensate of polaritons, and flocking of birds.
##### Physics Colloquium

May 21, 2020
Zoom | Thursday, 3:30 pm

## Cody Long, Cornell University

#### Constraints on Standard Model Constructions in F-theory

I will argue that the following three statements cannot all be true: (i) our vacuum is a type IIB /F-theory vacuum at moderate-to-large h^{1,1}, (ii) the \alpha^\prime-expansion is controlled via the supergravityapproximation, and (iii) there are no additional gauged sectorsfrom seven-branes. I will motivate this in large-scale ensemble studies in F-theory, and discuss the possible phenomenological consequences.
##### Theory Seminar

May 20, 2020
Zoom | Wednesday, 1:30 pm

## David Mazziotti, University of Chicago

#### Some Recent Advances in Quantum Computing for Quantum Chemistry

Quantum computing has the potential to transform our ability to predict chemistry from quantum mechanics. In this talk I will discuss some recent advances in quantum computing for quantum chemistry in my research group.
##### Chemistry

May 18, 2020
Zoom | Monday, 3:45 pm

## Chong Wang, Perimeter Institute

#### A theory of deconfined pseudo-criticality

It has been proposed that the deconfined criticality in (2+1)d - the quantum phase transition between a Neel anti-ferromagnet and a valence-bond-solid (VBS) - may actually be pseudo-critical, in the sense that it is a weakly first-order transition with a generically long correlation length. The underlying field theory of the transition would be a slightly complex (non-unitary) fixed point as a result of fixed points annihilation. This proposal was motivated by existing numerical results from large scale Monte-Carlo simulations as well as conformal bootstrap. However, an actual theory of such complex fixed point, incorporating key features of the transition such as the emergent SO(5)symmetry, is so far absent. Here we propose a Wess-Zumino-Witten (WZW) nonlinear sigma model with level k=1, defined in 2+ϵ dimensions, with target space S^(3+ϵ) and global symmetry SO(4+ϵ). This gives a formal interpolation between the deconfined criticality at d=3 and the SU(2)_1 WZW theory at d=2 describing the spin-1/2 Heisenberg chain. The theory can be formally controlled, at least to leading order, in terms of the inverse of the WZW level 1/k. We show that at leading order, there is a fixed point annihilation at d*≈2.77, with complex fixed points above this dimension including the physical d=3 case. The pseudo-critical properties such as correlation length, scaling dimensions and the drifts of scaling dimensions as the system size increases, calculated crudely to leading order, are qualitatively consistent with existing numerics.

May 18, 2020
Zoom | Monday, 1:30 pm

## Touch base

Feel very free to bring an amusing tidbit or video, or zoom trick or google drive trick, or hat trick or Comment

See you at noonish tomorrow

As you saw from last week, you don't have to wait until I arrive and you can stay after I leave.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

May 15, 2020
Zoom | Friday, 12:00 pm

## Wen Wei Ho, Harvard

May 11, 2020
Zoom | Monday, 1:30 pm

## a gas that thinks for itself

Drift in around noon, show-and-tells are encouraged.
12:15 is the main event.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch

##### MRSEC Baglunch

May 8, 2020
Zoom | Friday, 12:00 pm

## Jeremias Aguilera Damia, Centro Atomico Bariloche

May 4, 2020
Zoom | Monday, 1:30 pm

## Dmitry Krotov, IBM Research

#### A Few Ideas from Neurobiology and Physics for Unsupervised Learning

Abstract

Despite great success of deep learning, a question remains to what extent the computational properties of deep neural networks are similar to those of the human brain, and how the biological systems can further inform design of new algorithms for machine learning. In this talk, I will present two ideas from neurobiology: local learning motivated by Hebbian plasticity and sparse expansive network motifs present in olfactory systems of many organisms. These ideas can be used for designing a learning algorithm and network architectures that make it possible to learn powerful representations in an unsupervised way - directly from unlabeled data. Learning these representations does not require a backpropagation training. Instead, it utilizes local biologically plausible layer-wise learning, which is significantly faster than the backpropagation training. The utility of these algorithms will be demonstrated on classification and similarity search and retrieval tasks. I will also describe a simple dynamical system of particles moving under repulsive forces that captures an intuition behind the proposed learning algorithm.
##### JFI Special Seminar

May 1, 2020
Zoom | Friday, 1:00 pm

## Self Introductions

#### Origami Bit

Bring an unfolded sheet of office paper and you too can make the Origami Bit, in just four folds. A little opener before the main event.

If you want to play, bring a picture to show about a science thing that you like, and tell who you are and what group you're in. Put those things on your picture, too. Please keep this self-introduction to a minute or less

The time is 12:00, to shoot the breeze, tell jokes or news, and eat
Then at 12:15 we can also listen to each other's self introductions.

For the Zoom link, please signup to the baglunch mailing list: https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

May 1, 2020
Zoom | Friday, 12:00 pm

## On Growth and Form

#### The coffee stain, revisited

Meet and greet at noon
at Zoom

Main event: 12:15

https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

April 24, 2020
Zoom | Friday, 12:00 pm

## Getting under the skin of non-Hermitian skin modes

Self assembly: noon at Zoom
(Feel free to arrive early; I will aim to be there before noon.)

Self actuation: 12:15

https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

April 17, 2020
Zoom | Friday, 12:00 pm

## Mikhail Shapiro, California Institute of Technology

##### Molecular Engineering

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

## Touch base…

#### with luck, an old friend or two will come and say hi

Bring food to Zoom at 12:00

Bring something funny or cute to be screen-shared if you have it.

https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

April 10, 2020
Zoom | Friday, 12:00 pm

## Gabriel Orebi Gann, UC Berkeley

##### Physics Colloquium

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

#### the evolution of mutation rates

Bring food to Zoom at 12:00

Bring something funny or cute to be screen-shared
Hear about the cross-eyed genes at 12:15

https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

April 3, 2020
Zoom | Friday, 12:00 pm

## Kang Kuen Ni, Harvard University

##### Physics Colloquium

April 2, 2020
KPTC 106 | Thursday, 3:30 pm

## Slack Talk

https://lists.uchicago.edu/web/info/mrsec-baglunch"
##### MRSEC Baglunch

March 27, 2020
Zoom | Friday, 12:00 pm

## Zoom Lunch

#### Bring a Tidbit

Hi everyone -- It would be good to see you after a vertiginous week. By this time you might have a good joke or picture or web site to show. Meanwhile, the MRSEC leaders were busy with last Monday's virtual reverse site visit, and Margaret Gardel agreed to give us a brief update

https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

March 20, 2020
Zoom | Friday, 12:00 pm

## Steven Cundiff, Department of Physics, University of Michigan

#### Optical Multidimensional Coherent Spectroscopy of Semiconductor Nanostructures

The concept of multidimensional Fourier transform spectroscopy originated in NMR where it enabled the determination of molecular structure. The key concept is to correlate what happens during multiple time periods between pulses by taking a multidimensional Fourier transform. The presence of a correlation, which is manifest as an off-diagonal peak in the resulting multidimensional spectrum, indicates that the corresponding resonances are coupled. Migrating multidimensional Fourier transform spectroscopy to the optical regime is difficult because phases are critical. I will give an introduction to optical two-dimensional coherent spectroscopy, using an atomic vapor as simple test system, but also show unexpected results due to atomic interactions. I will then present our use of it to study optical resonances in semiconductor nanostructures including quantum wells, self-organized quantum dots and colloidal nanocrystals.Host: Christopher Melnychuk via email at cmelnychuk@uchicago.edu. 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 17, 2020
GCIS W301 | Tuesday, 3:45 pm

## Alexander Eychmüller,Technische Universität Dresden

#### Chemistry and physics of nanocrystals, 2D materials and aerogels: Review of my group’s current research

##### Chemistry

March 13, 2020
Kent 120 | Friday, 1:45 pm

## Peko Hosoi, MIT

##### Physics Colloquium

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

#### A Laboratory Analog of the Parker Spiral

Many rotating stars have magnetic fields that interact with the winds they produce. The Sun is no exception. The interaction between the Sun's magnetic field and the solar wind gives rise to the heliospheric magnetic field -- a spiraling magnetic structure, known as the Parker Spiral, which pervades the solar system. In this talk, I will report the creation of a laboratory model of the Parker spiral system based on a rapidly-rotating plasma magnetosphere and the measurement of its global structure and dynamic behavior. This laboratory system exhibits regions where the plasma flows evolve similarly to many magnetized stellar winds. We observe the advection of magnetic field into an Archimedean spiral and the ejection of quasi-periodic plasma blobs into the stellar outflow, which mimics the observed plasmoids that fuel the slow solar wind. The Parker spiral system mimicked in the laboratory can be used for studying solar wind dynamics in complementary fashion to conventional space missions such as NASA's Parker Solar Probe mission.
##### Computations in Science

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

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

#### Cancelled

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

## Chen Yang, Boston University

#### Design Photoacoustic Nanomaterial Interface to Fire and Reconnect Neurons

##### Chemistry

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

## Ohyun Kwon, UCLA

#### Beyond Phosphine Organocatalysis

##### Chemistry

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

## Burak Guzelturk, Argonne National Laboratory

#### Monitoring Photoinduced Structural Responses in Functional Photoactive Materials

##### Chemistry

March 9, 2020
GCIS E223 | Monday, 2:30 pm

## Jordan Cotler - Stanford University

#### Emergent unitarity in de Sitter from matrix integrals

I will discuss Jackiw-Teitelboim gravity with positive cosmological constant as a model for de Sitter quantum gravity. We will explore the quantum mechanics of the model, and show that there is a Hilbert space of asymptotic states at past and future infinity, along with an S-matrix encoding infinite-time evolution. This evolution is not unitary, although it is unitary on a subspace of asymptotic states, up to non-perturbative corrections. This non-unitary is due to universes which evolve into a crunch singularity. We also study topology-changing processes including the nucleation of baby universes. There is significant evidence that this 1+1 dimensional model is dual to a 0+0 dimensional matrix integral. We find that the Hilbert space and time evolution comprising the 1+1D de Sitter physics arise rather robustly from universal properties of the level repulsion of eigenvalues in the random matrix theory.

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

## Allison Narayan, University of Michigan

#### Biocatalysis and complex molecule synthesis

##### Chemistry

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

## 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, 3:00 pm

## Kai Zhang, PhD, Biochemistry UIUC

#### Bidirectional optical control of neurotrophin signaling during cell differentiation and embryonic development

The neurotrophin signaling pathway regulates a wide spectrum of cellular functions such as cell survival, proliferation, differentiation, and apoptosis. It also plays a key role in cell fate determination during embryonic development. Evidence suggests that the signaling output of the neurotrophic pathway varies with its temporal kinetics. However, a quantitative delineation of signaling kinetics is limited due to a lack of tools that allows precise control of the neurotrophic signaling in time and space. Non-neuronal optogenetics, an emerging technology that utilizes light to control intracellular signaling pathways, offers an alternative solution to address this challenge. In this presentation, I will introduce optogenetic systems recently developed in our laboratory that allow for reversible and bidirectional optical control of the neurotrophin signaling pathway in intact cells and in developing Xenopus laevis embryos. I will also discuss the limitations of current non-neuronal optogenetics and update you with current progress in the field in overcoming these limitations.
##### Biophysical Dynamics

March 3, 2020
GCIS W301 | Tuesday, 12:00 pm

## Moungi Bawendi, Massachusetts Institute of Technology

#### Playing with excitations and light: Perovskite nanoparticles as a potential source of quantum light, and Short Wave Infrared In-Vivo Bio-imaging.

##### Chemistry

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

#### S-matrix chaos and thermodynamics

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

## Eliot Kapit, Colorado School of the Mines

#### Noise-Tolerant Quantum Speedups in Quantum Annealing Without Fine Tuning

Quantum annealing is a powerful alternative model for quantum computing, which can succeed in the presence of environmental noise even without error correction. However, despite great effort, no conclusive proof of a quantum speedup (relative to state of the art classical algorithms) has been shown for these systems, and rigorous theoretical proofs of a quantum advantage generally rely on exponential precision in at least some aspects of the system, an unphysical resource guaranteed to be scrambled by random noise. In this work, we propose a new variant of quantum annealing, called RFQA, which can maintain a scalable quantum speedup in the face of noise and modest control precision. Specifically, we consider a modification of flux qubit-based quantum annealing which includes random, but coherent, low-frequency oscillations in the directions of the transverse field terms as the system evolves. We show that this method produces a quantum speedup for finding ground states in the Grover problem and quantum random energy model, and thus should be widely applicable to other hard optimization problems which can be formulated as quantum spin glasses. Further, we show that this speedup should be resilient to two realistic noise channels ($1/f$-like local potential fluctuations and local heating from interaction with a finite temperature bath), and that another noise channel, bath-assisted quantum phase transitions, actually accelerates the algorithm and may outweigh the negative effects of the others. The modifications we consider have a straightforward experimental implementation and could be explored with current technology
##### JFI Special Seminar

February 28, 2020
GCIS E223 | Friday, 1:00 pm

## Alberto Fernandez-Nieves, Georgia Tech and University of Barcelona

#### Active nematics & topological defects in curved and flat space

We will discuss recent results with active nematics confined to either toroidal or flat space. We will first describe how curvature affects defect arrangement on tori. We will show that despite the intrinsic activity and out-of-equilibrium character of the system, there are still remnants of the expected curvature-induced defect unbinding predicted for nematics in their ground state. Activity, however, augments the behavior leading to unexpected defect distributions. We will then focus on defect orientation and show that on flat space, there is short-range orientational correlations without long-range orientational order.

Friday, 28 FEBRUARY 12:00 noon: conversation over baglunch
12:15 seminar begins
##### MRSEC Baglunch

February 28, 2020
GCIS E123 | Friday, 12:00 pm

## Eric Sharpe, Virginia Tech

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

## Denis Bartolo, ENS Lyon

#### Flocks and crowds: a Gulliver trave

For centuries, applying an external pressure difference has remained the only solution to flow a liquid in a pipe. Over the last ten years, by engineering soft materials from self-propelled units, we have learned how to drive fluids from within. In the first part of my talk I will show how to assemble spontaneously flowing liquids from interacting colloidal robots. I will then show how to infer the hydrodynamics of these active fluids from the sole inspection of their fluctuation spectra. In the second part of my talk I will show that the same concepts and tool can be effectively use to account for the flows of pedestrian crowds walking on the streets of a windy city.
##### Computations in Science

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

## Dominika Zgid, Department of Chemistry, University of Michigan

#### Towards Accurate Quantum-Mechanical Calculations beyond Density Functional Theory

I will present a detailed discussion of self-energy embedding theory (SEET) which is a quantum embedding scheme allowing us to describe a chosen subsystem very accurately while keeping the description of the environment at a lower cost. SEET is applied to molecular examples where commonly our chosen subsystem is made out of a set of strongly correlated orbitals while the weakly correlated orbitals constitute an environment. Such a self-energy separation is very general and to make this procedure applicable to multiple systems a detailed and practical procedure for the evaluation of the system and environment self-energy is necessary. I will focusing our discussion on many practical implementation aspects such as the choice of best orbital basis, impurity solver, and many steps necessary to reach chemical accuracy.
Finally, on a set of carefully chosen molecular and solid examples, I will demonstrate that SEET, which is a controlled, systematically improvable Green's function method can be as accurate as established wavefunction quantum chemistry methods. Host: David Mazziotti via email damazz@uchicago.edu or at 4-1762. Persons with a disability who may need assistance please contact Brenda Thomas by email at bthomas@uchicago.edu or at 2-7156.
##### The Tuesday JFI Seminar

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

## Glenn Wagner, Oxford University

#### How to realize the quantum Hall effect in curved space in strained graphene

The quantum Hall effect in curved space has been the subject of many theoretical investigations in the past, but devising a physical system to observe this effect is hard. Previous work has indicated that electronic excitations in strained graphene realize Dirac fermions in curved space in the presence of a background pseudo-gauge field, providing an ideal playground for this. However, the absence of a direct matching between a numerical, strained tight-binding calculation of an observable and the corresponding curved space prediction has hindered realistic predictions. In this talk, I will sketch how to derive the low-energy Hamiltonian from the tight-binding model and map it to the curved-space Dirac equation. Using a strain profile that produces a constant pseudo-magnetic field and a constant curvature, one can compute the Landau level spectrum with real-space numerical tight-binding calculations and find excellent agreement with the prediction of the quantum Hall effect in curved space. I will conclude by discussing experimental schemes for measuring this effect.

February 25, 2020
MCP 201 | Tuesday, 1:30 pm

## Sarah Reisman, California Institute of Technology

#### Necessity is the Mother of Invention: Natural Products and the Chemistry They Inspire

##### Chemistry

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

## 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.

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

## Hill Harman, University of California - Riverside

#### Boron-Doped Acenes for the Redox Activation of Small Molecules

##### Chemistry

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

## Suri Vaikuntanathan, University of Chicago

#### Robustness in minimal models of biochemical oscillators

Biochemical oscillations are ubiquitous in biology and allow organisms to properly time their biological functions. Two biologically relevant observables in these biochemical oscillator circuits are the coherence and time period of oscillations. In this talk, I will discuss minimal Markov state models of non-equilibrium biochemical networks that support oscillations. In particular, I will discuss how a high energy consumption budget can make these quantities robust in a variety of settings.
##### Computations in Science

February 19, 2020
KPTC 206 | Wednesday, 12:15 pm

## Alex Spokoyny UCLA

#### Boron Cluster Building Blocks and Synthetic Reagents

##### Chemistry

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

###### Mon 17

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

## Too much semiannual amplitude in the daily temperature

#### Who ordered that?

Really talk about the weather: 12:15
##### MRSEC Baglunch

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

## William Lanouette, Atomic Heritage Expert and Author

##### Physics Colloquium

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

## Jianfeng Lu, Duke University

#### Coordinate-Descent Full Configuration Interaction

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

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

## 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

## Jeremy England, GSK AI

#### Cancelled

##### Computations in Science

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

## Yun Liu, University of Illinois

#### New Functions in Organic Materials through Molecular Designs

##### Chemistry

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

## 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

## Eric Kool, Stanford University

#### Designer Nucleotides and Molecular Probes of DNA Repair

##### Chemistry

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

## 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.

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

## Capturing the texture of a fracture by quantitative measures

Mangiamo 12:00
Parliamo 12:15
##### MRSEC Baglunch

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

## Meg Urry, Yale University

#### 2020 Equity, Diversity and Inclusion Colloquium

##### Physics Colloquium

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

## Xufeng Zhang, Center for Nanoscale Materials, Argonne National Laboratory

#### Experimental Observation of an Exceptional Surface in Hybrid Magnonic Systems

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

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

## 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

## Tobin Marks, Northwestern University

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

##### Chemistry

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

## Mufan Li, University of California Berkeley

#### Designing Electrocatalytic Sites at the Atomic Level

##### Chemistry

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

## Rebecca Kramer-Bottiglio, Yale University

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

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

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

## Tobin Marks, Northwestern University

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

##### Chemistry

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

## 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.

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

## 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

## Jessie Shelton, UIUC

#### Exploring the Cosmologies of Dark Sectors

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

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

## Alex Levine, UCLA

#### Cancelled

##### Computations in Science

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

## 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

## 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

## 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

## Stefano Sacanna, New York University

#### Engineering Colloidal Matter

##### Molecular Engineering

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

## 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

## 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.

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

## 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

## 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

## Elisabeth Bik, Harbers Bik LLC

#### Research Misconduct - The Dark Side of Science

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

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

## Jolene Reid, University of Utah

#### Data Science Tools for Selectivity Prediction in Chiral Phosphoric Acid Catalysis

##### Chemistry

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

## Rebecca Schulman, The John Hopkins University

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

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

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

## Martin Bazant, MIT

#### Shock Electrodialysis for Ion-Selective Water Purification

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

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

## Rebecca Schulman, Johns Hopkins University

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

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

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

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

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

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

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

## Tao Xie, Zhejiang University

#### Dynamic Covalent Polymer Networks

##### Molecular Engineering

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

## José Faraldo-Gómez, PhD, NHLBI, NIH

#### Exploring how membrane proteins influence membrane morphology and vice versa

##### Biophysical Dynamics

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

## Diana Iovan, University of California - Berkeley

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

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

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

#### actin filaments have one floppy end

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

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

## Andreas Wallraff, ETH Zurich

#### Realizing Fault-Tolerant Superconducting Quantum Processors

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

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

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

## Joshua Buss, University of Wisconsin

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

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

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

## Wim van Rees, MIT

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

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

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

## Christopher Jarzynski, University of Maryland, College Park

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

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

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

#### Explorations in Cold Collisions and Magnetometry with Atoms in Optical Tweezers

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

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

## Philip Shushkov, California Institute of Technology

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

##### Chemistry

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

## Y. Shirley Meng, University of California San Diego

#### Advanced Characterization for Long Life High Energy Battery Materials

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

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

## Chris Jarzynski, University of Maryland

#### Scaling down the laws of thermodynamics

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

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

## Po-Shen Hsin, Caltech

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

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

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

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

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

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

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

## how DNA can alter actin's nematic defects

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

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

## Angela Olinto, University of Chicago

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

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

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

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

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

#### Observation of Dynamical Phase Transitions in Cold Atomic Gases

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

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

## Eric Dufresne, ETH Zürich

#### The Mechanics of Soft Interfaces

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

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

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

## Eric Dufresne, ETH Zürich

#### Growing Droplets in Cells and Gels

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

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

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

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

## Luca Delacretaz, Uchicago

#### Hydrodynamic Tails in CFT and the Large Delta Expansion

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

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

## W. Benjamin Rogers, Brandeis University

#### Programming dynamic pathways to self-assembly using DNA nanotechnology

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

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

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

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

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

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

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

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

## Francesco Paesani, University of California San Diego

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

##### Chemistry

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

## Chaoming Jian, Stanford

#### Measurement-indeed criticality in random quantum circuits

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

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

## Physics with A Bang! Holiday Lecture and JFI Open House

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

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

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

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

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

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

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

## Art McDonald, Queen’s University, Canada

#### Deep Underground Measurements in Fundamental Physics and Astrophysics

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

##### Physics Colloquium

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

## Irmgard Bischofberger, MIT

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

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

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

## Philip E. Dawson PhD, Department of Chemistry, Scripps

#### Chemoselective ligation - from protein engineering to DNA encoded libraries

##### Biophysical Dynamics

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

## Victor Galitski, Department of Physics, University of Maryland

#### Quantum Lyapunov Exponents

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

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

## Tom Muir, Princeton University

#### Painting Chromatin with Synthetic Protein Chemistry

##### Chemistry

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

## Gregory Falkovich, Weizmann Institute of Science

#### Wonders of viscous electronics

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

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

## Andrea Alu, CUNY Advanced Science Research Center

#### Metamaterials Based on Broken Symmetries

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

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

## Michael Murrell - Department of Physics & Biomedical Engineering

#### Broken Time Reversal Symmetry and the Efficiency of Biological Machines

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

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

## Jing-Yuan Chen, Stanford

#### Enhanced Thermal Hall Effect in Nearly Ferroelectric Insulators

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

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

## David Grier Prize Minisymposium

#### David Grier Prize in Innovation in Biophysical Sciences Finalist Minisymposium

David Grier Prize inInnovation in Biophysical Sciences Finalist Minisymposium

Featuring

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

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

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

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

## Thomas E. Albrecht-Schmitt, Florida State University

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

##### Closs Lecture

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

## Ramis Movassagh, Cambridge Research Center

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

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

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

## Brainstorming about MRSEC open house

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

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

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

to get on this mailing list, go to
https://lists.uchicago.edu/web/info/mrsec-baglunch
##### MRSEC Baglunch

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

## Vanessa Wood, Chair, MaDe, ETH Zürich

#### Understanding and Optimizing Solution- Processed Systems

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

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

## Rebecca Willett, University of Chicago

#### Leveraging physical models in machine learning

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

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

## Michael Crommie, University of California-Berkeley

#### Using Topology to Engineer Bottom-Up-Synthesized Graphene Nanoribbons

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

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

## Nigel Goldenfeld PhD, Physics, UIUC

#### Stochastic Turing patterns in oceans, brains & biofilms

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

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

## Latha Venkataraman, Columbia University

#### Quantum interference based single-molecule insulators

##### Chemistry

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

## Victor-luca Iliesiu, Princeton University

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

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

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

## Matthew Sigman, University of Utah

#### Integrating Data Science Tools into Reaction Development

##### AbbVie Lecture

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

## Joseph Checkelsky, MIT

#### Synthesizing “Toy Model” Quantum Materials

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

Event Type
##### Physics Colloquium

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

## Orit Peleg, University of Colorado

#### Collective Ecophysiology and Physics of Honeybees

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

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

## Margaret Johnson, Department of Biophysics - Johns Hopkins University

#### Control of Multi-Protein Self-Assembly by Membrane Localization

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

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

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

#### Structural insights to the mechanism of Vps4 & other AAA unfoldases

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

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

## Laura Gagliardi, University of Minnesota

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

##### Chemistry

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

## Yu-An Chen, Caltech

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

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

## Emily Balskus, Harvard University

#### Deciphering the human microbiota using chemistry

##### Closs Lecture

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

## Wiggling in time

#### Using AFM to image polymer interfacial terrain

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

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

## Lars Peter Hansen, University of Chicago

#### Climate Change: Uncertainty and Economic Policy

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

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

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

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

## Anatoli Polkovnikov, Department of Physics, Boston University

#### Constructing Local Counterdiabatic Protocols in Complex Systems

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

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

## Bill Baker, Skidmore, Owings & Merrill LLP

#### Maxwell, Rankine, Airy and Modern Structural Engineering Design

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

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

## Mehran Kardar, Department of Physics, MIT

#### Diversity, Tolerance, and Maturation of the Adaptive Immune Response

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

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

## Masahiro Hotta, Tohoku University

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

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

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

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

#### Bacterial growth laws & the origin of dimensional reduction

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

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

## Jefferson Chan, University of Illinois, Urbana-Champaign

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

##### Chemistry

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

## The gel that knew too much

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

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

## Zhirong Huang, Stanford University

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

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

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

## Lukas Muechler

#### Flatiron Institute, New York

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

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

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

## Yonggang Huang Walter P. Murphy Professor of Engineering Northwestern University

#### Mechanics-guided Deterministic 3D Assembly

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

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

## Ben Nachman, Lawrence Berkeley National Laboratory

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

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

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

## Ben O'Shaughnessy, Columbia University

#### How Does the Actomyosin Contractile Ring Divide Cells?

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

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

## Ray Moellering:,University of Chicago

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

##### Chemistry

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

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

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

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

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

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

## Jennifer Prescher, University of California, Irvine

#### Spying on Cellular Communication with Chemical Tools and Noninvasive Imaging

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

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

## Donna Strickland, University of Waterloo Event Type

#### Generating High-Intensity, Ultrashort Optical Pulses

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

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

## David Schwab, CUNY

#### How noise affects the Hessian spectrum in overparameterized neural networks

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

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

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

#### Benchmarking Quantum Computers and Future Directions for Superconducting Quantum Hardware

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

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

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

#### Imaging-based live cell CRISPRi screening

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

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

## Suri Vaikuntanathan, University of Chicago

##### Chemistry

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

## Ying Lin, Caltech

#### Anomalies and Bounds on Charged Operators

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

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

## Gregory Girolami, University of Illinois

##### Chemistry

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

## Sand castles with quantum dots

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

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

## Cristina Marchetti, University of California Santa Barbara

#### Active Topology

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

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

## Rebecca Kramer-Bottiglio, Yale University

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

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

##### Computations in Science

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

## Joerg Wrachtrup, University of Stuttgart,Germany

#### Nanoscale quantum sensing

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

##### PME Distinguished Colloquium

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

## Dmitry Abanin, University of Geneva

#### Non-Equilibrium Dynamics Through the Prism of Quantum Entanglement

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

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

## Stefano Sacanna, New York University

#### Engineering Colloidal Matter

##### Chemistry

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

## Jeff McMahon, University of Michigan

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

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

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

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

#### Chiral charge dynamics in Abelian gauge theories at finite temperature

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

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

## Out in the PSD & PME Exhibit and Speaker Series

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

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

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

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

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

## Shinsei Ryu, University of Chicago

#### Holographic Quantum Matter and Entanglement Negativity

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

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

## Ed Bertschinger, MIT

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

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

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

## Massimiliano Delferro, PhD., Argonne National Laboratory

#### Catalytic Recycling and Upcycling of Polyofins

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

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

###### Thu 10

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

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

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

## Feng Wang, Department of Physics, University of California Berkeley

#### Engineering Correlation and Topology in Two-Dimensional Moire Superlattices

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

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

## Arvind Murugan, University of Chicago

#### Transients in physics and biology

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

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

## Cory Dean, Department of Physics - Columbia University

#### Engineering 2D Materials With a Twist

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

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

## Sophie Dumont, PhD, Cell & Tissue Biology, UCSF

#### Cell Division: Mechanical Integrity with Dynamic Parts

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

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

## John Anderson, University of Chicago

#### Synthesis and Reactivity of a Terminal Co Oxo Complex

##### Chemistry

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

## Anton Kapustin, Caltech

#### Chiral central charge and the Thermal Hall effect on the lattic

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

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

## How to cook a turbulent puff using vortex rings

#### How does nature eat it up?

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

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

## David Miller, University of Chicago

#### Exploring the Particle Universe at the Energy Frontier

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

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

## Daniel Fisher, Stanford University

#### Evolution, Ecology, and Chaos: Questions and Simple Models

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

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

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

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

##### Molecular Engineering

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

#### "Ask me anything” with the Physical Review Editors

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

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

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

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

## Aparna Baskaran, Department of Physics - Brandeis University

#### Active Matter: Applying Materials Physics Paradigm to

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

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

## Will Greenleaf, Stanford

#### Exploring the physical genome…

##### Biophysical Dynamics

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

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

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

##### Closs Lecture

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

## Boris Rybtchinski, Weizmann Institute of Science

#### Noncovalent Aqua Materials

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

##### Molecular Engineering

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

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

#### Mapping the inner world of cells

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

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

## Anatoly B. Kolomeisky, Rice Univerity

#### When Will the Cancer Start?

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

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

## Macropolis: A Chicagoland Polymer Symposium

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

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

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

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

## Claudia Felser, Max Planck Institute Chemical Phyics of Solids

#### Magnetic Weyl Semimetals

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

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

## Efi Efrati, Weizmann Institute of Science

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

##### Computations in Science

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

## Closs Lecture: Professor Zahra Fakhraai: University of Pennsylvania

#### Understanding Glass Transition Through Interfacial Properties

##### Chemistry

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

## Alexei Tkachenko, Center for Functional Nanomaterials, Brookhaven National Laboratory

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

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

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

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

## Liquid crystal elastomer gnocchi

12:00 eat. Don't eat the gnocchi
##### MRSEC Baglunch

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

## Professor Dr. Kallol Ray, Humboldt-University Berlin

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

##### Chemistry

August 28, 2019
| Wednesday, 1:15 pm

## James Sellers, PhD, NHLBI, NIH

#### Probing the motile & mechanical properties of nonmuscle myosin 2

##### Biophysical Dynamics

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

## Étienne Fodor, University of Cambridge

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

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

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

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

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

#### Measuring protein phase equilibria in situ via quantitative phase microscopy

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

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

## Development of a 100 GeV tabletop particle collider…

#### with sound

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

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

## Some like it tense

#### or how proteins detect osmotic load

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

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

## transverse shocks in an odd viscosity medium

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

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

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

## Nancy Forde, Department of Physics, Simon Fraser University

#### Interrogating protein flexibility and stability at the single-molecule level

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

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

## Graham R. Fleming

#### 70th Birthday Symposium

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

Program:

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

##### JFI Special Seminar

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

## on leaves, flowers and seed slugs

#### geometry and mechanics

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

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

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

#### Surprises in the Self-Assembly of Particles in Spherical Confinement

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

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

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

#### Cryo-EM studies on membrane transporters reveal new mechanistic insights

##### Biophysical Dynamics

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

## Nanoparticle Templating of Ultra-thin and Highly Porous Polymer Membranes

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

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

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

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

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

##### JFI Special Seminar

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

## Supercritical Water

#### from universality to personality

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

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

## IBD Science@theInterface

#### Machine Learning in Biology

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

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

11:15-12:00
Reverse-engineering Stochastic Dynamics: Quasi-species Evolution, Complex Disease Processes and Beyond

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

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

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

2:30-3:00 break

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

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

4:30 Reception
##### Biophysical Dynamics

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

## Matt Jaffe, University of California, Berkeley

#### Atom interferometry in an optical cavity

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

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

## Thomas Chalopin, Collège de France

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

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

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

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

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

## Niklas Mueller, Brookhaven National Laboratory

#### Constructing phase space distributions with internal symmetries

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

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

## Aishwarya Kumar, Penn State University

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

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

##### JFI Special Seminar

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

## Critical exceptional point:

#### From Bose-Einstein condensate to active matter

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

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

## David Saltzberg, University of California Los Angeles

#### How did Amy and Sheldon win their Nobel Prize?

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

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

###### Thu 6

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

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

## IME Distinguished Colloquium Series - Ralph Colby

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

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

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

## Atac Imamoglu, ETH Zurich

#### Many-body Optical Excitations in Solid-State Systems

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

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

## Carlos Bustamante: University of California,Berkeley

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

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

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

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

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

## Carlos Bustamante: University of California,Berkeley

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

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

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

## Amos Yaron, Technion

#### Probing anomalous driving

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

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

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

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

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

## Xiaoming Mao, University of Michigan

#### Topological floppy modes in aperiodic networks and a mechanical duality theorem

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

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

## Josh Vura-Weis, Department of Chemistry - UIUC

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

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

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

## Congjun Wu (UCSD)

#### Symmetry and Correlation Aspects of Quantum Dynamics

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

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

## Teri W. Odom: Northwestern University

#### Plasmon-molecule Interactions in Confined Volumes

##### Chemistry

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

## Elizabeth Simmons, University of California San Diego

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

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

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

## IME Distinguished Colloquium Series - Sven Rogge

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

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

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

## Joshua Shaevitz, Princeton University

#### Self-driven phase transitions in living matter

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

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

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

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

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

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

## Greg Verdine: Harvard University

#### Pages from the Playbook of Nature

##### Chemistry

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

## Alexios Pilychronakos

#### Generalized Calogero Models and their Hydrodynamics

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

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

## Matthew B. Francis, University of California, Berkeley

#### Versatile Oxidative Coupling Reactions for Site-Selective Protein Modification

##### Chemistry

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

## Ania Bleszynski Jayich, University of California Santa Barbara

#### TBA

##### Physics Colloquium

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

## Anne McNeil: University of Michigan

#### Precision Conjugated Polymer Synthesis & Applications

##### Chemistry

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

## Martin Falk

#### Simple models for (mostly) biological heterpolymers

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

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

## David Lentik, Stanford

#### Avian Inspired Design

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

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

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

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

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

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

## Michael Green: University of California, Irvine

#### Insights into biological C-H bond activatiion

##### Chemistry

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

## Luis Bettencourt, University of Chicago

#### TBA

##### Physics Colloquium

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

## IME Distinguished Colloquium Series - Darrell Irvine

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

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

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

## Thierry Emonet, Yale University

#### Conflicts and synergies between individuality and collective behavior

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

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

## Zohar Komargodski, Weizmann

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

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

## Bruce Berne, Columbia University

#### Molecular Dynamics: a Personal Retrospective

##### Rice-Berry Lecture

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

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

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

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

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

## Gregory Fu, CALTECH

#### Photoinduced, Copper-Catalyzed Substitution Reactions of Alkyl Electrophiles

##### Kharasch Lecture

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

## Malleable matter: Designing disordered metamaterials by natural aging

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

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

## FORUM 2019

#### Facilities Open-house Research Users Meeting

FORUM 2019
Facilities Open-house Research Users Meeting

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

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

What is the FORUM?

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

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

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

Register Now!

Who is this meeting for?

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

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

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

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

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

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

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

## Phil Morrison, University of Texas, Austin

#### Joint CAM Colloquium

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

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

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

## Kawtar Hafidi, Argonne National Laboratory

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

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

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

## Rafael Jaramillo, The Department of Materials Science, MIT

#### Mechanism and New Applications of Large and Persistent Photoconductivity

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

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

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

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

#### Viscoelastic response of quantum Hall states

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

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

## Pankaj Mehta, Boston University

#### Toward a Statistical Mechanics of Microbiomes

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

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

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

## Gregory Fu, CALTECH

#### Nickel-Catalyzed Substitution Reactions of Alkyl Electrophiles

##### Kharasch Lecture

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

## Jay Foley, The Department of Chemistry, William Patterson University

#### Jay Foley, The Department of Chemistry, William Patterson University

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

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

## Kharasch Lecture: Professor Gregory Fu, Caltech

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

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

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

## Kristan Jensen, San Francisco State University

#### de Sitter, SYK, and coadoint orbits

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

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

#### Colloids and liquids from suspensions to superhydrophobicity

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

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

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

## Professor Yan Xia: Stanford University

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

##### Chemistry

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

## Herbert Mayr, Ludwig-Maximilians-Universität München

#### Mythology in Organic Chemistry: How Obsolete Concepts Survive

##### Chemistry

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

## Ritchie Patterson, Cornell University

#### Mastering Bright Electron Beams

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

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

## Andrew Houck, The Department of Electrical Engineering, Princeton University

#### Many-body Quantum Optics in Superconducting Circuits

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

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

## IME Distinguished Colloquium Series - Jeffrey Moore

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

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

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

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

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

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

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

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

## Risi Kondor, University of Chicago

#### Covariant neural network architectures for learning physics

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

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

## Joseph Mindell, MD-PhD, NINDS-NIH

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

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

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

## Yogi Surendranath: MIT

#### Bridging Molecular and Heterogeneous Electrocatalysis Through Graphite Conjugation

##### Chemistry

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

## Jon Sorce, Stanford University

#### Tensor Networks and Emergent Spacetime in AdS/CFT

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

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

## Mechanical duality

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

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

## AbbVie Visit Day

#### Hosted by Chemistry and My CHOICE

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

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

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

## Rob Phillips, California Institute of Technology

#### How Schrodinger's Cat Became a Cat

##### Physics Colloquium

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

## Detlef Lohse, University of Twente

#### Evaporation of multicomponent droplets

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

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

## Johanna Knapp, University of Vienna

#### GLSMs, CYs, and Localization

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

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

## Nikta Fakhri, MIT

#### Thermodynamics of active matter

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

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

## Lulu Qian, The Department of Bioengineering, Caltech

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

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

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

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

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

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

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

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

## Eric Klein, PhD, Rutgers University-Camden

#### Adaptation to phosphate-limitation in Caulobacter crescentus

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

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

## Thomas Muir: Princeton University

#### Painting Chromatin with Synthetic Protien Chemistry

##### Chemistry

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

## Emil Yuzbashyan, Rutgers University

#### Integrable time-dependent Hamiltonians

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

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

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

## The heart of crumpling

#### or how to (in)crease your core

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

The story begins at 12:15
##### MRSEC Baglunch

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

## William Unruh, University of British Columbia

#### Experimental Measurement of the Hawking emission (?)

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

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

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

## Bernhard Breit, Albert-Ludwigs - University Freiburg

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

##### Special Organic Syntheses Lecture

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

## IME Distinguished Colloquium Series - Rohit Karnik

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

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

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

## Oskar Hallatschek, UC Berkeley

#### The role of jackpot events in the dynamics of evolution

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

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

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

#### Stimulated Emission by Colloidal Quantum Dots

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

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

## Monika Scholz, PhD, Princeton

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

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

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

## Richa Batra, Creative Machines Lab, Columbia University

#### Particle Robotics: Statistical Mechanics of Loosely Coupled Robotic Components

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

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

## Floyd Romesberg, The Scripps Research Institute

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

##### Closs Lecture

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

## Zhihao Zhuang, University of Delaware

#### Chemical Approaches for Investigating Protein Deubiquitination

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

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

## Luca Grandi, University of Chicago

#### TBA

##### Physics Colloquium

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

## Christof Sparr, University of Basel

#### Cataltic Cascade Reactions Inspired by Polyketide Biosynthesis

##### Special Organic Syntheses Lecture

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

## Semyon Klevtsov, University of Cologne

#### Geometric responses of Quantum Hall states

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

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

## Greg Bewley, Cornell University

#### The structure of turbulence and of granular beds

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

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

## David Weiss, The Department of Physics, Penn State University

#### Quantum Computing with Neutral Atoms

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

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

## Nan Hao, PhD. UCSD

#### Systems biology of single-cell aging

##### Biophysical Dynamics

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

## Brian M. Stoltz, California Institute of Technology

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

##### Bristol-Myers Squibb Lecture

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

## Nicholas Meanwell, Bristol-Myers Squibb

#### Inhibitors of HIV-1 Maturation

##### Bristol-Myers Squibb Lecture

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

## Ronak Soni, Stanford University

#### Scalar Asymptotic Charges and Dual Large Gauge Transformations

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

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

## Arvind Murugan, University of Chicago

#### Materials that learn from examples

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

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

## Muhittin Mungan, University of Bonn

#### Cyclic Annealing, Random Maps & Memories

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

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

## IME Distinguished Colloquium Series - Alberto Salleo

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

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

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

## Hana El-Samad, University of California, San Francisco

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

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

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

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

#### Visualization of Topological States of Matter Using Microwave Impedance Microscopy

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

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

## Raymond Kapral, University of Toronto

#### Molecular Machines and Synthetic Motors: Active Motion on Nanoscales

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

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

## Guanyu Zhu, IBM T.J. Watson Research Center

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

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

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

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

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

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

## Ramón Latorre, PhD, University of Valparaíso, Chile

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

##### Biophysical Dynamics

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

#### Enantioselective Chemical Synthesis Methods via Cooperative Catalysis

##### Chemistry

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

## Maciej Koch-Janusz, ETH, Zurich

#### Information Theory, Machine Learning and the Renormalization Group

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

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

## Jennifer Dionne, PhD, Stanford University

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

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

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

## William A. Tisdale, MIT

#### Excitons, Entropy, and Nonequilibrium Transport in Semiconductor Nanomaterials

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

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

## Xiangfeng Duan, UCLA

#### Van der Waals Integration Before and Beyong 2D Materials

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

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

## Frank Graziani, Lawrence Livermore National Laboratory

#### High Energy Density Physics and Modeling of Extreme States of Matter

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

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

## John Briggs PhD, LMB-MRC

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

##### Biophysical Dynamics

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

## Richard Schrock, MIT

#### Recent Advances in Olefin Metathesis with Molybdenum Catalysts

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

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

## Jennifer Lin, IAS

#### Entanglement in gauge theories and gravity

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

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

## Jennifer Roizen, Duke University

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

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

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

## Jane Wang, Cornell University

#### Insect Flight: from Newton’s law to Neurons

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

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

## Thomas V. Magee, Senior Research Director at Pfizer

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

##### Chemistry

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

## Amy Weeks, University of California, San Francisco

#### New Chemoenzymatic Tools for Dissecting Proteolytic Signaling Pathways

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

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

## Xiang Cheng, University of Minnesota

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

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

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

## Arjun Yodh, The Department of Physics & Astronomy

#### Soft Matter Potpourri

##### The Tuesday JFI Seminar

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

## Istvan Racz, University of Warsaw

#### On the use of evolutionary methods in spaces of Euclidean signature

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

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

## Jessica McIver, Caltech

#### Gravitational wave astrophysics: a new era of discovery

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

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

## Daniel Jafferis, Harvard University

#### Stringy ER=EPR

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

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

## Marc Kamionkowski, Johns Hopkins University

#### Heretical hypotheses in the hunt for dark matter

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

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

## Greg Voth, Wesleyan University

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

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

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

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

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

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

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

## Ibrahim Cisse, Physics, MIT,

#### Super-resolution imaging of transcription in live mammalian cells

##### Biophysical Dynamics

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

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

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

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

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

## Jim Sethna, Cornell University

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

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

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

## Andrei Starinets, University of Oxford

#### Analytic structure of hydrodynamic expansions at large finite coupling

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

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

## Jörn Dunkel, MIT

#### Wrinkles and spaghetti

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

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

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

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

#### Molecular Polaritons – Janus Particles of Photon and Molecules

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

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

#### The Statistical Mechanics of Hydrogen Bonding at the Liquid Water Interface

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

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

## Dima Abanin, University of Geneva

#### New quantum many-body states enabled by erodicity breakdown

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

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

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

## Cathy Drennan, HHMI / MIT

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

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

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

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

#### Naturalness in the Sky

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

##### Theory Seminar

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

## Dancing nano-particles in a strobe light

Prelude 12:00
Fugue 12:15
##### MRSEC Baglunch

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

## Vidya Madhavan, University of Illinois at Urbana–Champaign

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

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

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

## Particle Phenomenology Seminar: Masha Baryakhtar

#### Searching for New Physics with Light and Gravitational Waves

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

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

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

## Andrej Košmrlj, Princeton University

#### Phase separation in multicomponent liquid mixtures

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

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

## Emily Weiss - The Department of Chemistry, Northwestern University

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

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

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

## Tania Baker, Department of Biology, Massachusetts Institute of Technology

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

##### Biophysical Dynamics

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

## Particle Phenomenology Seminar: Zhen Liu

#### A pathway to the next discovery

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

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

## Kharasch Mini Symposium

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

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

## Hannes Pichler, Harvard

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

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

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

## Special Seminar (Particle Phenomenology): Andrea Thamm, CERN

#### Beyond the Standard Model: Beyond the LHC

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

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

## Peggy Mason, University of Chicago

#### Empathy: The good, the bad, and the ugly

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

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

## Kadanoff Special Seminar: Gil Young Cho, Postech

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

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

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

## Nichole Yunger Halpern, Harvard

#### Quantum steampunk: Quantum information meets thermodynamics

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

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

## Bryan Dickinson, University of Chicago

#### Synthetic Biology Approaches to Study and Exploit RNA Regulation

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

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

## Particle Phenomenology Seminar: Simon Knapen

#### Searching for whispers from beyond the standard model

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

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

## Arthur Barnard, Stanford University

#### New tools for probing classical and quantum nanomaterials

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

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

## Gurol Suel, University of California San Diego

#### The resilience & dichotomy of bacterial existence

##### Biophysical Dynamics

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

## Jennifer Lippincott-Schwartz, HHMI

#### Peering Into Cells with New Imaging Technologies

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

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

## Hoi Chun Po, MIT

#### Symmetry shortcuts to topological materials

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

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

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

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

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

## Pablo Jarillo-Herrero, Massachusetts Institute of Technology

#### Magic Angle Graphene: a New Platform for Strongly Correlated Physics

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

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

## Shenshen Wang, Physics & Astronomy, UCLA

#### Discovering generalist solutions in rough & changing landscapes

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

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

## Shmuel Rubinstein, Harvard

#### The physics of crushing and smashing: Cascades and cataclysmic change

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

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

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

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

## Andrew Potter, Honeywell

#### Entanglement dynamics and topology in driven systems

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

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

## Special Seminar (Particle Phenomenology): Prateek Agrawal

#### Axions at the discovery frontier

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

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

## Edbert Sie, Stanford

#### How to Control Quantum Materials with Light

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

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

## Odd elasticity: soft engines from active solids

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

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

## Dominic Else, MIT

#### Topological phases of matter with spatial symmetries

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

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

## Special Seminar (Particle Phenomenology): Yue Zhang

#### New Dark Matter Signals in Neutrino Detectors

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

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

## Eric Spanton, UC Santa Barbara

#### Fractional Chern insulators in graphene heterostructures

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

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

## Margaret Gardel, University of Chicago

#### Controlling the Shape of Cells within Tissue

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

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

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

#### Multifunctional & Multidimensional Super-resolution Microscopy

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

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

## Ryo Nakano, Nagoya University

#### Study on Olefin Polymerization Toward Utilization of Carbon Dioxide

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

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

## Why do my flying lego blocks spin and make hinges?

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

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

## Reina Maruyama, Yale University

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

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

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

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

#### Machine Learning Collective Variable Discovery in Colloidal Assembly and Protein Folding

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

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

## Su-Yang Xu, MIT

#### Topology and Geometry in Quantum Materials

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

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

##### Special JFI Seminar

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

## Marc-André Légaré, University of Würzburg

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

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

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

## Katharine Diehl, Princeton University

#### Illuminating Epigenetic Mechanisms in Cancer with Designer Chromatin

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

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

## winner take all: from neural networks to nucleation

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

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

## Paola Ruggiero (SISSA and INFN)

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

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

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

## Sebastian Huber, Department of Physics, ETH Zürich

#### Axial Magnetic Fields in Weyl Systems

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

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

## Dianne J. Xiao, Stanford University

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

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

## Chiara Daraio, Caltech

#### Tunable, On-chip Phononic Devices Operating at MHz Frequencies

Nanoelectromechanical systems (NEMS) that operate in the megahertz (MHz) regime allow energy transducibility between different physical domains. For example, they convert optical or electrical signals into mechanical motions and vice versa. This coupling of different physical quantities leads to frequency-tunable NEMS resonators via electromechanical non-linearities. In this talk, I will describe one- and two-dimensional, non-linear, nanoelectromechanical lattices (NEML) with active control of the frequency band dispersion in the radio-frequency domain (10–30 MHz). Our NEMLs consist of a periodic arrangement of mechanically coupled, free-standing nanomembranes with circular clamped boundaries. This design forms a flexural phononic crystal with a wide and well-defined bandgap. The application of a d.c. gate voltage creates voltage-dependent on-site potentials, which can significantly shift the frequency bands of the device. Additionally, I will discuss the experimental realization of topological nanoelectromechanical metamaterials with protected edge states. These on-chip integrated acoustic components could be used in unidirectional waveguides and compact delay lines for high-frequency signal-processing applications.
##### Computations in Science

December 12, 2018
KPTC 206 | Wednesday, 12:15 pm

## Prof. Sean T. Roberts, Department of Chemistry, University of Texas-Austin

#### Manipulating Energy and Spin for Photon Up- and Down-conversion

The negligible spin-orbit coupling in many organic molecules creates opportunities to alter the energy of excited electrons by manipulating their spin. In particular, molecules with a large exchange splitting have garnered interest due to their potential to undergo singlet fission (SF), a process where a molecule in a high-energy spin-singlet state shares its energy with a neighbor, placing both in a low-energy spin-triplet state. When incorporated into photovoltaic and photocatalytic systems, SF can offset losses from carrier thermalization, which account for ~50% of the energy dissipated by these technologies. Likewise, compounds that undergo SF’s inverse, triplet fusion (TF), can be paired with infrared absorbers to create structures that upconvert infrared into visible light. In this presentation, I will review our group’s efforts to create organic:inorganic structures that use SF and TF for improved light harvesting and photon upconversion. Host: Andrei Tokmakoff, 4-7696 or via email at tokmakoff@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The Tuesday JFI Seminar

December 11, 2018
GCIS W301 | Tuesday, 4:00 pm

## Joaquín Rodríguez-López, University of Illinois at Urbana-Champaign

#### Elucidating Electrochemical Energy Materials Through Versatile Electrochemistry

In this seminar, I will discuss how new polymeric and low-dimensional materials, as well as an expanded electroanalytical toolbox for understanding interfaces, are allowing us to discover new synergies at the nano and mesoscale for emerging battery technologies. I will describe in detail one system where nano-scale heterogeneity has an impact on macro-scale performance: novel redox active polymers (RAPs) for size-selective flow batteries. Highly soluble RAPs are new players in redox flow technologies, and as part of our collaboration with the Joint Center for Research Energy Storage (JCESR), we are exploring the opportunities that macromolecular design offers for tuning their electrochemical performance. These investigations span across several areas of knowledge, from the interrogation of individual polymer particles, to the elucidation of new redox polyelectrolyte dynamics, and to the evaluation of flow battery performance. Finally, I will describe how we have applied insightful interfacial design and analysis to better understand other energy technologies such as ion batteries and electrocatalysts. Fundamental pursuit of electrode design principles have led us to investigate intercalation processes in low dimensional materials, and the use of ultra-thin electrodes for creating new charge transfer strategies on hetero-structures.
##### Molecular Engineering

December 11, 2018
ERC 201B | Tuesday, 10:00 am

## C. Rose Kennedy, Princeton University

#### Leveraging Mechanistic Insight to Enable Catalyst-Controlled Chemo-, Regio- & Stereoselective C–C Bond Formation

Mechanistic elucidation provides potent tools for enabling the design of efficient and selective catalytic transformations. Examples of mechanism-guided method development, drawing from the complementary strengths of ion-pairing organocatalysis and organometallic chemistry to achieve selective C–C bond formation, are described.

In the former case, combined experimental and computational analyses delineating the mechanisms of representative amido-thiourea-catalyzed transformations are discussed. Insights from these studies enabled (i) the rational design of linked bis-thioureas that impart enhanced efficiency for enantioselective anion-abstraction catalysis and (ii) the introduction of a synergistic ion-binding strategy for asymmetric catalysis of transformations involving electronically diffuse transition structures.

In the latter case, iron complexes bearing redox-active ligands are explored as catalysts for hydrovinylation and cycloaddition reactions proceeding through the intermediacy of metallacycles. Mechanistically informed ligand designs are leveraged to control metallacycle formation and fate to upgrade olefinic coupling partners with control of chemo-, regio-, and diastereoselectivity. Applications of the resulting cycloadducts for the synthesis of fuels, polymers, and fine chemicals are discussed.
##### Chemistry

December 10, 2018
Kent 102 | Monday, 1:15 pm

## Physics with A Bang! Holiday Lecture and JFI Open House

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

Saturday, December 8th, 2018
Kersten Physics Teaching Center
5720 S. Ellis Ave., Chicago, IL

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

Doors for the Lectures open 30 minutes before each show. Please note: there will be no online registrations, and will be a first to arrive, first ticketed event. We do not guarantee availibility of seating, but shows will also be streamed live to alternate venues. Those needing special assistance, please send an email to ecs@uchicago.edu.
##### Special JFI Seminar

December 8, 2018
KPTC 106 | Saturday, 11:00 am

## Junichiro Yamaguchi, Waseda University

#### Making Bonds by Breaking Bonds: An Unconventional Approach to Making Molecules

##### Chemistry

December 7, 2018
Kent 120 | Friday, 1:15 pm

## Abigail Vieregg, University of Chicago

#### Discovering the Highest Energy Astrophysical Neutrinos Using a Radio Phased Array

Ultra-high energy neutrino astronomy sits at the boundary between particle physics and astrophysics. The detection of high energy neutrinos is an important step toward understanding the most energetic cosmic accelerators and would enable tests of fundamental physics at energy scales that cannot easily be achieved on Earth. IceCube has detected astrophysical neutrinos at lower energies, but the best limit to date on the flux of ultra-high energy neutrinos comes from the ANITA experiment, a NASA balloon-borne radio telescope designed to detect coherent radio Cherenkov emission from cosmogenic ultra-high energy neutrinos. The future of high energy neutrino detection lies with ground-based radio arrays, which would represent a large leap in sensitivity. I will discuss the demonstrated performance of a new radio phased array design that we have implemented on the ARA experiment at the South Pole and on the new BEACON experiment on White Mountain in California. The radio phased array has improved sensitivity to high energy cosmic particles and will push the energy threshold for radio detection down to overlap with the energy range probed by IceCube.
##### Physics Colloquium

December 6, 2018
KPTC 106 | Thursday, 4:00 pm

## Katlyn K. Meier, Stanford University

#### Spectroscopic Characterization of Unique Iron and Copper Active Sites in Biology

##### Chemistry

December 6, 2018
Kent 120 | Thursday, 12:30 pm

## Diana Qiu, University of California, Berkeley

#### Excitons in Flatland: Exploring and Manipulating Many-body Effects on the Optical Excitations in Quasi-2D Materials

Since the isolation of graphene in 2004, atomically-thin quasi-two-dimensional (quasi-2D) materials have proven to be an exciting platform for both applications in novel devices and exploring fundamental phenomena arising in low dimensions. This interesting low-dimensional behavior is a consequence of the combined effects of quantum confinement and stronger electron-electron correlations due to reduced screening. In this talk, I will discuss how the low-energy optical excitations (excitons) in quasi-2D materials, such as monolayer transition metal dichalcogenides and few-layer black phosphorus, differ from typical bulk materials. In particular, quasi-2D materials are host to a wide-variety of strongly-bound excitons with unusual excitation spectra and massless dispersion. The presence of these excitons can greatly enhance both linear and nonlinear response compared to bulk materials, making them ideal candidates for applications in optoelectronics, energy harvesting, and energy conversion. Moreover, due to enhanced correlations and environmental sensitivity, the electronic and optical properties of these materials can be easily tuned. I will discuss how substrate engineering, stacking of different layers, and the introduction or removal of defects can be used to tune the band gaps and optical selection rules in quasi-2D materials.
##### Molecular Engineering

December 6, 2018
ERC 201B | Thursday, 10:00 am

## Lou Charkoudian, Haverford College

#### Capturing Transient Interactions of Proteins Involved in Natural Product Biosynthesis

How do microorganisms produce chemically diverse and structurally complex molecules? How can humans harness this technology to better human health and the environment? These questions inspire our lab to study acyl carrier proteins (ACPs), which serve as central hubs in polyketide and fatty acid biosynthetic pathways. ACPs are notoriously challenging to study because the fast motions of the ACP phosphopantetheine (Ppant) arm make its conformational dynamics difficult to capture using traditional spectroscopic approaches. In this talk, I will present how the synthetic modification of the terminal thiol of the ACP Ppant arm can transform the ACP reactive site into a vibrational spectroscopic probe that can report on mechanistically-relevant movements of the ACP. I will share stories about how we leverage Ppant probes to resolve conformational dynamics on the picosecond time scale and visualize ACP complex formation with functional catalytic partners. We anticipate that these methods will be valuable in future structural and biosynthetic engineering studies because our approach is generalizable, practical, and scalable. Our studies combine concepts and techniques spanning biochemistry, organic chemistry, bioinformatics, and physical chemistry, and therefore I hope this talk will be of interest to a broad audience.
##### Chemistry

December 5, 2018
GCIS W301 | Wednesday, 1:00 pm

## David Lubensky, University of Michigan

#### Organ size, inflationary embryology, and the statistical physics of tissue growth

One of the enduring mysteries of biology is how organs know to stop growing at the correct size and how those sizes are coordinated so that the animal retains the correct proportions. Here, we discuss several studies that in different ways address the precision with which organ size can be controlled. We first show that there are severe limits to the coordination of the sizes of left and right organs (like the left and right wings of a fruit fly) by chemical signals, suggesting that organ size is set primarily autonomously. We then consider the noisy dynamics of the growth of individuals tissues in the presence of various feedback laws. We find that only certain forms of mechanical feedback can specify a unique organ size. We also show that, even in the simplest, homogeneous case, stochastic growth of an elastic tissue has unexpectedly rich behavior: For example, it exhibits power law correlation functions, reminiscent of those seen in cosmological models, and soft modes that allow for diffusive growth of labelled clones of cells.
##### Computations in Science

December 5, 2018
KPTC 206 | Wednesday, 12:15 pm

## Weixin Tang, Harvard University

#### From Peptide Antibiotics to CRISPR-mediated Synthetic Memories: Tools from the Microbial Arsenal

##### Chemistry

December 5, 2018
GCIS W301 | Wednesday, 11:00 am

## Prof. Christophe Delerue, IEMN- CNRS, Paris

#### Localized Surface Plasmon Resonance in Doped Semiconductor Nanocrystals

Nanocrystals of heavily-doped semiconductors have recently emerged as very promising materials for plasmonics. In contrast to nanocrystals of noble metals, their Localized Surface Plasmon Resonance (LSPR) can be easily tuned in energy by controlling the carrier concentration through doping. In addition, due to the low concentration of carriers compared to metals, the LSPR can be
extended to infrared and near-infrared ranges. Recent experimental studies have demonstrated the existence of LSPR in doped nanocrystals of Si and different types of oxides (ZnO, SnO2, In2O3). However, the physics of the LSPR in these nanocrystals is not totally understood. In the first part of my talk, I will give of general overview of the field of doped semiconductor nanocrystal
plasmonics. In the second part, I will review theoretical studies that we have performed in order to address fundamental issues which are still highly debated. The evolution with doping concentration of the optical processes from single-electron to many-electron transitions will be described. The conditions required for the emergence of collective modes will be discussed. The results of atomistic calculations will be compared with those of more classical approaches. The role of the quantum confinement and the influence of the dopant potential and location will be discussed. The intrinsic mechanisms at the origin of plasmon damping in doped nanocrystals will be analyzed. The results confirm that doped nanocrystals are very promising for the development of IR plasmonics.Host: Philippe Guyot-Sionnest,2-7161 or via email at pgs@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The 1st Tuesday JFI Colloquium

December 4, 2018
GCIS W301 | Tuesday, 4:00 pm

## Srimoyee Sen, University of Washington

#### Anyonic particle-vortex statistics and the nature of dense QCD

I discuss the recent theoretical observation of Z_3 -valued particle-vortex braiding phases in high density QCD and its implications for higgs-confinement complementarity. As a consequence of the braiding phases, certain mesonic and baryonic excitations, in the presence of a superfluid vortex, have orbital angular momentum quantized in units of 1/3. Such non-local topological features can distinguish phases whose realizations of global symmetries, as probed by local order parameters, are identical. If Z_3 braiding phases and angular momentum fractionalization are absent in lower density hadronic matter, as is widely expected, then the quark matter and hadronic matter regimes of dense QCD must be separated by at least one phase transition

December 4, 2018
PRC 201 | Tuesday, 1:30 pm

## Mark Levin, Harvard University

#### Catalytic Manipulation of Reactivity and Selectivity at High-Valent Nuclei

This presentation will examine aspects of reactivity and selectivity discovered through the exploration of the chemistry of high-valent nuclei [Au(III), Pt(IV), and I(III)]. The first part concerns two examples wherein transition metals are examined as substrates for catalytic reactions rather than in their traditional role as catalysts. Operating from this perspective, supramolecular catalysis of C(sp3)-C(sp3) reductive elimination and organoborane catalyzed C(sp3)-CF3 reductive elimination will be discussed, with the latter applied to [18F]-radiotrifluoromethylation. The second section will continue the focus on fluorination through the development of a new aryliodine catalyst for enantioselective olefin difluorination, exploring structural features that improve catalyst robustness and selectivity and enabling the preparation of chiral fluorinated building blocks.
##### Chemistry

December 3, 2018
Kent 120 | Monday, 1:15 pm

## Brad P. Carrow, Princeton University

#### Leveraging Polarizability and Electrophilicity in Catalysts for Challenging Coupling Reactions

A general approach by our group for the development of new catalytic synthetic methods that occur with higher efficiency and selectivity, use simpler reagents, and proceed with lower energy demand involves new ancillary ligand design coupled with fundamental studies of how metal-ligand bonding dictates catalytic reactivity. In this context, the presentation will focus on our recent efforts to discover new phosphorus- and sulfur-based ligands and associated metal catalysts that manifest special properties from seemingly "weak" interactions, for instance London dispersion. Two case studies will be discussed that exemplify such effects and emphasize many lessons yet to be learned about how structure controls reactivity in synthetic catalysts. In one case, a new transmetalation mechanism can be triggered in reactions of low-coordinate Pd complexes possessing polarizable diamondoid substituents, which enables smooth coupling catalysis even with historically unstable organoboron reagents. Studies of oxidative dehydrogenative coupling reactions will also showcase evidence for a C−H bond activation mechanism, termed electrophilic CMD or "eCMD", which has characteristics distinct from established SEAr and concerted metalation-deprotonation (CMD) pathways for C−H functionalization. Transition state analyses suggest this reaction pathway could be a general class of C−H activation manifested by many other transition metal catalysts, and selection rules have been identified for predicting what catalyst structures manifest either classic CMD or eCMD, which occur with unique substrate preferences and selectivity.
##### Chemistry

November 30, 2018
Kent 120 | Friday, 1:15 pm

## Junqi Li, Yale University

#### From Automated Small Molecule Synthesis to Understanding Chiral Phosporic Acid Catalysis

Efforts to discover and optimize new small molecule function are often impeded by limitations in synthetic access to small molecules. This is because small molecule syntheses typically employ strategies and purification methods that are highly customized for each target. Furthermore, the molecular interactions between the catalyst and substrate are often not understood in catalyst-controlled selective reactions, thus impeding the design of new and more selective catalysts. In this seminar, an iterative cross-coupling strategy that enables the systematized and automated synthesis of different types of small molecules will be presented. The second part of the talk will discuss enantio- and site-selective reactions catalyzed by chiral phosphoric acids with a focus on understanding key catalyst-substrate interactions.
##### Chemistry

November 29, 2018
Kent 120 | Thursday, 1:15 pm

## Andrei Parnachev

#### Regge limit in Holographic Conformal Field Theories

We will discuss the Regge limit of correlators in holographic CFTs and its
physical implications. Examples include constraints on the three-point couplings of the stress tensor
and the relation between heavy states in CFT and black holes in dual gravity.
##### Theory Seminar

November 28, 2018
PRC 201 | Wednesday, 1:30 pm

## Felice Frankel

#### More Than Pretty Pictures

Graphics, images and figures — visual representations of scientific data and concepts — are critical components of science and engineering research. They communicate in ways that words cannot. They can clarify or strengthen an argument and spur interest into the research process.

But it is important to remember that a visual representation of a scientific concept or data is a re-presentation and not the thing itself –– some interpretation or translation is always involved. Just as writing a journal article, one must carefully plan what to “say,” and in what order to “say it.” The process of making a visual representation requires you to clarify your thinking and improve your ability to communicate with others.

In this talk, I will show my own approach to creating depictions in science and engineering—the successes and failures. Included will be a discussion about how far can we go when “enhancing” science images.
##### Computations in Science

November 28, 2018
KPTC 206 | Wednesday, 12:15 pm

## Wheland Lecture: Professor Jack W. Szostak, Harvard University

#### The Surprising Chemistry of Nonenzymatic RNA Replication

The RNA genomes of the first cells are thought to have emerged from the nonenzymatic replication of short RNA strands. We have recently found that the template-directed reaction of a primer with activated nucleotide substrates proceeds through an unexpected covalent intermediate. Our kinetic and crystallographic studies have provided insight into the mechanism of this key reaction, and to improvements in RNA copying chemistry that are both more prebiotically plausible and more accurate, efficient, and general.
##### Chemistry

November 28, 2018
GCIS W301 | Wednesday, 12:00 pm

## Prof. Zahra Fakhraai, Department of Chemistry, University of Pennsylvania

#### Understanding Glass Transition Through Interfacial Properties

Free surfaces and interfaces can affect properties of glassy systems over length scales that can be much longer than the intermolecular interaction potential. A fundamental understanding of the magnitude and length scale of these effects can allow us to understand the glass transition phenomenon and engineer nano-scaled materials with unique properties. In this presentation I show two examples of such effects and their use in producing thermally and kinetically stable glass materials. Extensive research in the past two decades has shown that the free surface of glasses, in particular for polymeric and organic glasses, have dramatically faster dynamics, resulting in strong reduction in their glass transition temperature, Tg, in ultra-thin films. We have recently shown that the surface dynamics can be faster by as much as eight orders of magnitude resulting in an apparent glass to liquid transition in molecular glass films as thick as 30 nm. The details of the thickness-dependent relaxation dynamics in thin films can elucidate properties of bulk glass that are key in verifying glass transition models. The enhanced mobility over such a large length scale can also help produce stable glasses with unique molecular packing upon physical vapor deposition.

In another example, we demonstrated that polymers’ thermal stability can be significantly improved in highly confined geometries. Capillary rise infiltration (CaRI) is used to load randomly closed-packed films of nanoparticles with various polymers. By changing the NP diameter, polymer can be confined in length scales as small as 2-3 nm. Under these conditions, entropic and enthalpic effects induced by interfaces play the dominant role in stabilizing the polymer, leading to higher Tg, higher viscosity, and improved resistance to burning and thermal degradation. We discuss the role of various parameters in achieving these thermally stable states. Host: Julia Murphy, jgmurphy102@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The Tuesday JFI Seminar

November 27, 2018
GCIS W301 | Tuesday, 4:00 pm

## Yichen Hu, University of Pennsylvania

#### On the Brink of Fractionalization

Systems of strongly interacting particles can give rise to topological phases beyond non-interacting limit. Although unique features of strongly interacting topological phases, such as fractionalization of quantum degrees of freedom, have important applications in quantum information processing, these topological phases are still far from experimental realizations. In this talk, by presenting constructions of two strongly interacting topological phases, I will argue the key mechanism of their realizations is to add interactions near topological phase transitions. I will first introduce a model of interacting Majorana fermions that describes a superconducting phase with Fibonacci topological order. Then I will show that a correlated fluid of electrons and holes, dubbed fractional excitonic insulator phase, can exhibit a fractional quantum Hall effect at zero magnetic field. I will present physical evidence and conjecture that this phase can be realized in a higher angular momentum excitonic paired system in the presence of interactions.

November 27, 2018
PRC 201 | Tuesday, 1:30 pm

## Ethan Garner, PhD, Molecular and Cellular Biology, Center for Systems Biology, Harvard

#### Quantitating the motions of filaments gives insight into how bacteria grow as rods & control their rate of growth

Prof. Garner is hosted by Ed Munro and Sean Crosson
##### Biophysical Dynamics

November 27, 2018
GCIS W301 | Tuesday, 12:00 pm

## Wheland Lecture: Professor Jack W. Szostak, Harvard University

#### The Origin of Cellular Life

To understand the origin of life on Earth, and to evaluate the potential for life on exoplanets, we must understand the pathways that lead from chemistry to biology. Recent experiments suggest that a chemically rich environment that provides the building blocks of membranes, nucleic acids and peptides, along with sources of chemical energy, could result in the emergence of replicating, evolving cells. I will discuss physical mechanisms that enable the growth and division of model protocells, the possible nature of primordial RNA, and the chemistry of its replication.
##### Chemistry

November 26, 2018
Kent 120 | Monday, 4:00 pm

## Emily Sprague-Klein, Northwestern University

#### Hot Electrons & Transient Molecular Dynamics in Plasmonic Nanomaterials

Excitation of localized surface plasmon resonances yield non-equilibrium carrier populations that can then be harnessed to drive site-specific chemical processes at the nanoscale. We demonstrate the first direct detection of the molecular anion radical generated from plasmon-driven electron transfer in tightly confined sub-nanometer gaps under intense visible light irradiation. The energetics of these transient hot electron chemical processes are catalogued in a range of polypyridyl complexes in corroboration with open-shell density functional theory. Techniques for the observation of molecule-surface structural dynamics with high temporal and spatial resolution are discussed. The findings have broad applicability towards designing organic-inorganic hybrid microelectronics and nanoscale chemical reactors for surface redox reactions on the subnanometer scale. Host: Sarah King, 4-3809 or via email to sbking@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### JFI Special Seminar

November 26, 2018
GCIS W301 | Monday, 1:30 pm

## Tania Baker, Department of Biology, Massachusetts Institute of Technology

##### Biophysical Dynamics

November 21, 2018
GCIS W301 | Wednesday, 1:00 pm

## Gabriel Won

#### Glueing together Modular flows with free fermions

e revisit the calculation of multi-interval modular Hamiltonians for free fermions using a Euclidean path integral approach. We show how the multi-interval modular flow is obtained by glueing together the single interval modular flows. Our methods are based on a derivation of the non-local field theory describing the reduced density matrix, and makes manifest it's non-local conformal symmetry and $U(1)$ Kacs-Moody symmetry. We will show how the non local conformal symmetry provides a simple calculation of the entanglement entropy.

November 20, 2018
PRC 201 | Tuesday, 1:30 pm

## Gregory R. Bowman, PhD, Washington University

#### Identifying & Exploiting Protein Shape-shifting

A protein is a dynamic shape-shifter whose function is determined by the set of different structures it adopts. Unfortunately, it is often impossible to experimentally characterize most of these structures with the atomic resolution one would like in order to gain mechanistic insight or design drugs and mutations. The Bowman lab is combining enhanced sampling methods, such as Markov state models (MSMs), with biophysical experiments to overcome this limitation. Using this integrative approach, we are coming to a better understanding of how allosteric signals are transmitted between distant parts of a protein. We are also uncovering cryptic pockets that are absent in available experimental structures and provide new targets for drug development. To test our insights, we are designing and experimentally characterizing small molecules and mutations that exert allosteric control over distant functional sites. Examples of ongoing projects include (1) understanding how mutations give rise to antibiotic resistance, (2) designing allosteric drugs to combat antibiotic resistant infections, (3) understanding allosteric networks in G proteins and designing allosteric anti-cancer drugs, and (4) understanding and interfering with the mechanisms of Ebola infection.
##### Biophysical Dynamics

November 20, 2018
GCIS W301 | Tuesday, 12:00 pm

## Professor Matthew Bogyo, Stanford University

#### Chemical Tools for Identification and Imaging of Hydrolases Involved in the Pathogenesis of Cancer and Infectious Disease

Hydrolases are enzymes that often play pathogenic roles in many common human diseases such as cancer, asthma, arthritis, atherosclerosis and infection by pathogens. Therefore, tools that can be used to dynamically monitor their activity can be used as diagnostic agents, as imaging contrast agents and for the identification of novel enzymes and drug leads. In this presentation, I will describe our efforts to design and synthesize small molecule probes that produce a fluorescent signal upon binding to a hydrolase target. In the first part of the presentation, I will discuss probes targeting the cysteine cathepsins and their application to real-time fluorescence guided tumor resection and other diagnostic imaging applications. In the second half of the presentation, I will present our efforts to identify novel hydrolases in the pathogenic bacteria Staphylococcus aureus that could be targeted to enable both treatment and non-invasive imaging of disease progression.
##### Chemistry

November 19, 2018
Kent 120 | Monday, 4:00 pm

## Professor Oren Petel, Department of Mechanical and Aerospace, Engineering Carleton University

#### Impact Injury Evaluation and Mitigation Strategies Using X-ray Imaging

##### JFI Special Seminar

November 19, 2018
GCIS E223 | Monday, 1:30 pm

## Alex Turzillo, Caltech

#### Free and Interacting Short-Range Entangled Phases of Fermions: Beyond the Ten-Fold Way

It is well-known that sufficiently strong interactions can destabilize some SPT phases of free fermions, while others remain stable even in the presence of interactions. It is also known that certain interacting phases cannot be realized by free fermions. In this talk, we will study both of these phenomena in low dimensions and determine the map from free to interacting SPT phases for an arbitrary unitary symmetry. We will also describe how to compute invariants characterizing interacting phases for free band Hamiltonians with symmetry (in any dimension) using only representation theory.

November 16, 2018
PRC 364 | Friday, 1:30 pm

## Closs Lecture: Professor Lewis Rothberg, University of Rochester

#### What You Don't See Can Hurt You: The Dark Matter Problem in Luminescent Conjugated Polymers

High luminescence yields in solution bode well for easily processed conjugated polymers as the emissive species in photopumped film lasers, biological tags and display technology. The luminescence efficiency in the solid state, however, is often found to be low even when the polymer is doped dilutely into inert hosts. Our recent research involves trying to systematically vary morphology at the single chain level to illustrate the interplay between energy transfer amongst chromophores and aggregation of chromophores in determining the photophysics. We find dramatic variations in behavior as the polymer morphology evolves from extended to collapsed. In the intermediate case, we observe surprising and instructive phenomena that cannot be explained in the context of previous literature models. For example, we show that it is possible to greatly increase photoluminescence by deliberate selective photooxidation of low energy but poorly emitting chromophores. Consequences of this finding include intense luminescence spikes in single chain spectroscopy and the ability to post-process some bulk polymer samples to improve their luminescence efficiency. A revised model of the photophysics accounts for these phenomena and explains the failure of luminescence to scale with molecular weight, an observation fondly labeled “the dark matter problem” by Ivan Scheblykin.
##### Chemistry

November 16, 2018
Kent 120 | Friday, 1:15 pm

## Prof. Frederico Toschi, The Department of Applied Physics, Eindhoven University of Technology (ATU/e)

#### Genetic Competition in Weakly Compressible Turbulent Flows

The genetic competition for biological species living in marine environments can be severely influenced by fluid advection. Very often, in oceans and in lakes, cell generation times are precisely in the inertial range of eddy turnover times and therefore the influence of turbulence must be properly taken into account. We employ both an off-lattice agent-based simulation as well as an on-site density-based model to describe two competing populations in one and in two spatial dimensions under the influence of advecting (turbulent) velocity fields. The novel on-site density-based model allows to accurately and efficiently describe the dynamics of the population and the genetics of large number of individuals, making this the ideal tool to study populations in two dimensions. We find that the presence of compressible turbulent velocity fields can have a very strong effect on genetic competitions. In particular, even in regimes where the overall population structure is approximately unaltered, the flow can significantly diminish the effect of a selective advantage on fixation probabilities. We explain this effect in terms of the enhanced survival of organisms born at the sources in the flow and the influence of Fisher genetic waves. We find for both cases that even in a regime where the overall population structure is approximately unaltered, the flow can significantly diminish the effect of a selective advantage on fixation probabilities. We understand this effect in terms of the enhanced survival of organisms born at sources in the flow and of the influence of Fisher genetic waves. Host: Vincenzo Vitelli, 2-7206 or via email at vitelli@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### JFI / IME Seminar

November 16, 2018
GCIS E123 | Friday, 12:15 pm

## Giorgio Gratta, Stanford University

#### Measuring gravity at short distances and other fun tricks with levitated microspheres

##### Physics Colloquium

November 15, 2018
KPTC 106 | Thursday, 4:00 pm

## Chen-Te Ma, National Taiwan University

#### Bell’s Inequality, Generalized Concurrence and Quantum Entanglement

We demonstrate an alternative evaluation of quantum entanglement by measuring maximum violation of Bell's inequality without performing a partial trace operation in an n-qubit system by bridging maximum violation of Bell's inequality and a generalized concurrence of a pure state. This proposal is realized when one subsystem only contains one qubit and a quantum state is a linear combination of two product states. Finally, a relation of the generalized concurrence of a pure state and the maximum violation of Bell's inequality is also demonstrated in a 2n-qubit state.

November 15, 2018
PRC 201 | Thursday, 2:00 pm

## Tony Gherghetta

#### Naturalizing SUSY with the Relaxion and the Inflaton

##### Theory Seminar

November 14, 2018
PRC 201 | Wednesday, 1:30 pm

## Oni Basu, University of Chicago

#### Single-cell Transcriptomics and Biology using Microfluidics

The basic units of biological structure and function are cells, which exhibit wide variation in regard to both type and state. We assess such variation by simultaneously profiling the transcriptomes of thousands of single mammalian cells (Drop-seq) or nuclei (DroNc-seq), using high-throughput emulsion microfluidics and DNA barcodes. These are accomplished by (a) encapsulating and lysing one cell/nuclei per emulsion droplet, and (b) barcoding RNA contents from each cell/nuclei using unique DNA-barcoded micro-beads, (c) performing Next-Gen Sequencing.

We are using these droplet-based techniques to profile cell types comprising complex tissues in a variety of tissue-types such as the heart and solid tumors in mouse models and human primary tissue. Besides, we are using Drop-seq and DroNc-seq to profile cell-states, particularly cellular heterogeneity in development and differentiation processes using a combination of cell lines, mouse embryonic tissue, in vitro culture, and human induced pluripotent stem cells.

We also develop custom microfluidic devices to study phenotypic responses of cells to different environmental stimuli including physical, bio-chemical and pathogenic stimuli; I will provide some examples to illustrate some applications.
##### Computations in Science

November 14, 2018
KPTC 206 | Wednesday, 12:15 pm

## The Tuesday JFI Seminar - Prof. Aashish Clerk, IME, The University of Chicago

#### Driven-dissipative Quantum Phenomena: from Synthetic Non-reciprocity to New Kinds of Topology

In this talk, I’ll give an introduction to theory work in my group focused on understanding and exploiting driven-dissipative quantum phenomena in engineered quantum systems. I’ll start by discussing work showing how engineered dissipation can make almost any kind of interaction between two subsystems non-reciprocal (i.e. uni-direcitonal). This is provides a systematic approach for designing quantum systems with one-way interactions, with applications ranging from new kinds of quantum measurement devices to unusual many-body effects. In the second part of the talk, I’ll focus on work exploring how two-photon (parametric) driving can be used to realize new kinds of topological bosonic systems. While these systems have Hamiltonians analogous to topological superconductors, their physics is remarkably distinct from their fermionic partners. Among other things, I’ll discuss the surprising properties of a bosonic version of the Kitaev-Majorana chain, and how these ideas could be realized with superconducting quantum circuits. Host: Timothy Berkelbach, 4-9879 or via email at berkelbach@uchicago. Persons with a disability who may need assistance please contact Brenda Thomas 2-7156 or by email to bthomas@uchicago.edu.
##### The Tuesday JFI Seminar

November 13, 2018
GCIS W301 | Tuesday, 4:00 pm

## Hart Goldman, Illinois

#### Dirac Composite Fermions and Emergent Reflection Symmetry about Even Denominator Filling Fractions

Motivated by the appearance of a “reflection symmetry” in transport experiments and the absence of statistical periodicity in relativistic quantum field theories, we propose a series of relativistic composite fermion theories for the compressible states appearing at filling fractions 1/2n in quantum Hall systems. These theories consist of electrically neutral Dirac fermions attached to 2n flux quanta via an emergent Chern-Simons gauge field. While not possessing an explicit particle-hole symmetry, these theories reproduce the known Jain sequence states proximate to filling 1/2n, and we show that such states can be related by the observed reflection symmetry, at least at mean field level. We further argue that the lowest Landau level limit requires that the Dirac fermions be tuned to criticality, whether or not this symmetry extends to the compressible states themselves

November 13, 2018
PRC 201 | Tuesday, 1:30 pm

## Zhen Gu, PhD, UCLA

#### Leverage Physiology for Bioresponsive Drug Delivery

Spurred by recent advances in materials chemistry, molecular pharmaceutics & nanobiotechnology, stimuli-responsive “smart” systems offer opportunities for precisely delivering drugs in dose-, spatial- & temporal-controlled manners. In this talk, I will discuss our ongoing efforts in developing physiological signal-triggered bio-responsive drug delivery systems. I will first present the glucose-responsive synthetic systems for biomimetic delivery of insulin for diabetes treatment. Bio-responsive microneedle patches and vesicle fusion-mediated synthetic beta cells will be emphasized.
I will further discuss the local & targeted delivery of immunomodulatory therapeutics for enhanced cancer therapy. Our latest study utilizing platelets and injectable gels for targeted/local delivery of immune checkpoint inhibitors will be specifically introduced.
##### Biophysical Dynamics

November 13, 2018
GCIS W301 | Tuesday, 12:00 pm

## Mulliken Lecture: Professor Peter Rossky, Rice University

#### Translating the Message in Spectroscopic Probes of Conjugated Molecular Materials

Over recent decades, there have been a steadily increasing number of studies on electronically conjugated materials for use in solar photovoltaic cells, organic transistors, and fluorescent probes. Progress in using semiconducting polymers has been limited by a fundamental lack of knowledge at the nanoscale underlying variations in electro-optical behavior. Hence, in contrast to familiar silicon-based technology, there is a dearth of principles to drive the bottom-up design of material building blocks.
Experiments probe such materials by their response to light, i.e., spectroscopically. The challenge is to interpret the observations in molecular terms. Computational modeling based on the physics of atomistic details and explicit electronic structure is ideally suited to enabling this connection of spectra to structure, since the connection in modeling is unambiguous while the experiment provides a strong constraint on the validity of the model. In this presentation, I will discuss examples of conjugated molecular material systems studied by theoretical, modeling, and experimental approaches that elucidate both atomistic and electronic structure and dynamics in a way inaccessible to either theory or experiment alone. Examples from the area of conjugated polymers and also from biosensors based on GFP will be presented.
##### Chemistry

November 12, 2018
Kent 120 | Monday, 4:00 pm

## Professor David Sarlah, University of Illinois at Urbana-Champaign

#### Dearomative Functionalization Strategies and Synthesis of Anticancer Natural Products"

Small complex molecules are highly desired in all areas of chemistry, but they are also often difficult to access. Selective transformations of aromatic compounds could provide a more direct route to such desirable targets; however, the many challenges associated with dearomative functionalization have left these types of reactions widely underdeveloped. Our group has been developing new strategies that bridge the gap between dearomatization functionalization and alkene chemistry. In pursuit of this goal, we have developed dearomative functionalizations using small molecules – arenophiles – that enable reactions of isolated alkenes in aromatic substrates. Thus, well-established olefin reactions, such as dihydroxylation and reduction, can now be more directly applied to arenes. Additionally, arenophiles in combination with transition metal catalysis provide unique platform and enable the rapid access to a diverse range of products that are both challenging to synthesize via existing methods and complementary to those acquired through biological or chemical dearomative processes. Finally, using this methodology we have recently completed the synthesis of several complex anticancer natural products.
##### Chemistry

November 9, 2018
Kent 120 | Friday, 1:15 pm

## Transient driving that kinetically converts a foe into a friend

body food 12:00
brain food 12:15
##### MRSEC Baglunch

November 9, 2018
GCIS E123 | Friday, 12:00 pm

## Helen Quinn, SLAC

#### Science, Engineering and Art as well –why it is hard to teach science well

will reflect on what we know about teaching science for k-12 students and for undergraduates, how we know it, and what it tells us about good teaching. To teach well you must engineer the right learning conditions with careful design goals for what is to be learned, you must understand both the subject area you wish to teach and something of what research on learning tells us about critical aspects of learning that area (this is known as pedagogical content knowledge or content knowledge for teaching) and then you must be a skilled improvisational performance artist to pull off the lessons as intended, responding to the needs of students who enter your classroom with a wide range of prior knowledge, engaging them all as active participants in the learning.

This talk is based on work I have been doing in the area of science education since my retirement in 2010 from physics research, summarizing what I have learned in the process. Illinois and approximately 30 other states have adopted new science standards based on the NAS study “A Framework for k-12 science education” that I led. This study tried to capture the learning about learning from science education research as well as to shift the goals for what needs to be learned. I will discuss how it, together with research studies focused on teaching physics or other sciences at the undergraduate level, suggests changes in undergraduate teaching approaches as well.
##### Physics Colloquium

November 8, 2018
KPTC 106 | Thursday, 4:00 pm

## IME Distinguished Colloquium Series - Shanhui Fan, Stanford

#### Concepts of Nanophotonics and Energy Applications

Light, or electromagnetic waves, represent one of the most important carriers of heat and energy. New capabilities to manipulate light, as enabled by new classes of electromagnetic structures such as photonic crystals, metamaterials and plasmonic systems, therefore have significant implications for energy applications. In this talk, we will discuss some of these implications, illustrated by examples of our own recent works ranging from radiative cooling to dynamic wireless power transfer.

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

November 7, 2018
KCBD 1103 | Wednesday, 4:00 pm

#### Topological Origin of Equatorial Waves

Topology sheds new light on the emergence of unidirectional edge waves in a variety of physical systems, from condensed matter to artificial lattices. Waves observed in geophysical flows are also robust to perturbations, which suggests a role for topology. We show a topological origin for two celebrated equatorially trapped waves known as Kelvin and Yanai modes, due to the Earth’s rotation that breaks time-reversal symmetry. The non-trivial structure of the bulk Poincaré wave modes encoded through the first Chern number of value 2 guarantees existence for these waves. The invariant demonstrates that ocean and atmospheric waves share fundamental properties with topological insulators, and that topology plays an unexpected role in the Earth climate system.
##### Computations in Science

November 7, 2018
KPTC 206 | Wednesday, 12:15 pm

## 1st Tuesday Colloquium - Prof. Mark D. Ediger, University of Wisconsin-Madison

#### Exploring the Limits of Amorphous Packing with Ultrastable Glasses

Glasses formed by cooling a liquid inherit both their structure and their limited stability from the liquid state. In contrast, glasses prepared by vapor deposition can avoid both of these limitations. By utilizing the high mobility present near the free surface of many organic glasses, vapor deposition can build glasses with low enthalpy, high density, and high thermal stability. Based upon their position on the potential energy landscape, these materials approach “ideal glass” packing that otherwise could only be achieved by annealing a liquid-cooled glass for thousands or millions of years. Vapor deposition of organic semiconductors produces glasses with improved properties for organic electronics, including the ability to produce anisotropic glasses with a wide range of structures. Remarkably, this “anti-epitaxy” process uses the free surface structure as its template, rather than the substrate structure. Recent work has shown that optimizing vapor deposition can produce organic light emitting diodes (OLEDs) that are more efficient and have extended lifetimes. Host: Thomas Witten, 2-2-0948 or via email to t-witten@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The 1st Tuesday JFI Colloquium

November 6, 2018
GCIS W301 | Tuesday, 4:00 pm

## Andy LiWang, PhD, Quantitative and Systems Biol, UC Merced

#### Can proteins tell time?

Circadian clocks arose in organisms as an adaptation to the rotation of the earth. These clocks produce involuntary anticipation of sunrise and sunset by generating a succession of biochemical phases. In this talk, the mechanism of a model system, that of cyanobacteria, will be described. Briefly, it depends on phosphorylation, long-range allostery, dynamics, and protein metamorphosis. Because a simple mixture of clock proteins and ATP generate a persistent macroscopic rhythm, the mechanism of the clock can be studied in real time as it ticks. Now, signal transduction pathways have been reconstituted with the oscillator so that rhythmic transmission of clock signals can be studied in vitro.
##### Biophysical Dynamics

November 6, 2018
GCIS W301 | Tuesday, 12:00 pm

## Luca Delacretaz, Stanford University

#### Bounds on transport and thermalization from positivity

November 6, 2018
PRC 215 | Tuesday, 12:00 pm

## Professor Daniel G. Nocera, Harvard University

#### Food and Fuel from Sunlight, Air and Water

##### Chemistry

November 5, 2018
Kent 120 | Monday, 4:00 pm

## Naama Barkai, PhD, Molec Genetics and Physics, Weizmann

#### Robustness & scaling in embryonic development

Naama Barkai, PhD, Departments of Molecular Genetics and of Physics of Complex Systems, Weizmann Institute of Science is the 2018-19 Frederick Seitz Lecturer in Interdisciplinary Science.

Informal reception will follow Dr. Barkai's presentation in the lobby of the KCBD
##### Biophysical Dynamics

November 5, 2018
KCBD 1103 | Monday, 1:30 pm

## Professor Peter G. Wolynes, Rice University

#### Energy Landscape Theory: From Folding Proteins to Folding Chromosomes

The statistical mechanics of energy landscapes has resolved the paradoxes of how information-bearing matter can assemble itself spontaneously. I will explain how our current understanding of protein folding landscapes not only leads to successful schemes for predicting protein structure from sequence but also has given quantitative insight into how folding and function shape molecular evolution. While protein folding is, in the main, thermodynamically controlled and not kinetically limited, longer structures in the cell can assemble in a kinetically controlled, nonequilibrium fashion. Nevertheless, I will show how energy landscape theory provides tools for extracting from low resolution experimental structural methods and kinetic information about the structure and cooperative dynamics of chromosomes.'
##### Chemistry

November 2, 2018
Kent 120 | Friday, 1:15 pm

## Transient driving that kinetically converts a foe into a friend

Eat 12:00
Action 12:15
##### MRSEC Baglunch

November 2, 2018
GCIS E123 | Friday, 12:00 pm

## Marcos Santander, The University of Alabama

#### Exploring the high-energy sky with neutrinos and gamma rays

In 2013 the IceCube neutrino observatory, a cubic-kilometer particle detector deployed deep within the South Pole glacier, announced the first detection of an astrophysical flux of high-energy neutrinos in the TeV-PeV range. This breakthrough discovery has prompted a wide-ranging observational effort aimed at identifying the sources of the neutrino flux by combining IceCube measurements with observations spanning the entire electromagnetic spectrum. Gamma rays in particular provide a powerful tool to search for neutrino source counterparts as both particles are produced in high-energy hadronic interactions. The detection and study of neutrino sources would not only signify the start of a new form of astronomy, but could also solve long-standing questions in high-energy astrophysics such as the origin of high-energy cosmic rays. This talk will introduce the IceCube detector, summarize recent results from multi-messenger searches of neutrino sources and present an overview of current and future gamma-ray follow-up observations, especially with the Cherenkov Telescope Array, a ground-based facility for very-high-energy gamma-ray astronomy currently under construction.
##### Physics Colloquium

November 1, 2018
KPTC 106 | Thursday, 4:00 pm

## Saebyeok Jeong, Stony Brook

#### Opers, surface defects, and Yang-Yang functional

In this talk, I will introduce a gauge theoretical derivation of a correspondence which relates quantization of integrable system to symplectic geometry [1]. First, I will briefly review how the Hitchin integrable systems are associated with the class S theories. The Hitchin moduli space is identified with the moduli space of flat connecitons, with a distinctive Lagrangian submanifold of opers. It is suggested that the holomorphic functions on the space of opers are the (off-shell) spectra of the quantum Hitchin Hamiltonians [2]. Moreover, the conjecture in [4] states that the generating function for the space of opers is equal to the effective twisted superpotential of the class S theory on the two-dimensional omega-background. I will show a gauge theoretical derivation of the correspondence. The derivation involves the following key ingredients:
1) Use half-BPS codimension-two (surface) defects in the class S theories to construct the opers and their solutions.
2) Analytically continue the surface defects partition functions to build connection formulas of the solutions.
3) Construct a Darboux coordinate system relevant to the correspondence.
4) Compute the monodromies of opers from 2) and compare with the expressions from 3) The direct comparison establishes the desired identity.
##### Theory Seminar

October 31, 2018
PRC 201 | Wednesday, 1:30 pm

## Timothy C. Berkelbach, University of Chicago

#### Stochastic Quantum Chemistry

Exact many-particle quantum mechanics has a prohibitive cost that grows exponentially with the size of the system. Most modern quantum chemistry is built on approximations that result in more tractable algorithms with polynomial scaling, but which qualitatively fail for many important problems. I will describe an alternative approach that uses stochastic techniques to circumvent this prohibitive cost (i.e. a flavor of quantum Monte Carlo). In particular, this approach is based on a very general and recently-developed framework for stochastic linear algebra called "fast randomized iteration", due to Lim and Weare. I will describe the FRI algorithm, its application to challenging problems in quantum chemistry, and its advantages over similar techniques.
##### Computations in Science

October 31, 2018
KPTC 206 | Wednesday, 12:15 pm

## The Tuesday JFI Seminar - Prof. Christos Panagopoulos, Nanyang Techenilogical University, Singapore

#### Tunable Room Temparature Skyrmions

The electric field experienced by a travelling electron translates, in its rest frame, to a magnetic field proportional to its velocity – a relativistic effect which is notable in crystalline lattices with heavy atoms. The Zeeman interaction between the electron spin and this effective magnetic field is equivalent to the coupling of the electronic spin and momentum degrees of freedom, known as spin-orbit coupling (SOC). Importantly, SOC effects are greatly enhanced in reduced dimensions: inversion symmetry is broken at the surface or interface, and the resultant electric field couples to the spin of itinerant electrons. Host: Timothy Berkelbach, 4-9879 or via email to berkelbach@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.

The states induced by engineering SOC and inversion symmetry breaking in magnetic materials open a broad perspective, with impact in the technology of spin topology. For example, in conventional ferromagnets the exchange interaction aligns spins and the anisotropy determines energetically preferred orientations. Meanwhile, the interaction generated by SOC and broken inversion symmetry induces a relative tilt between neighbouring spins. Magnetic skyrmions – finite-size two-dimensional (2D) ’whirls’ of electron spin – form due to the competition between these ‘winding’ & ‘aligning’ exchange interactions.

Skyrmions have several compelling attributes as prototype memory elements, namely their (1) nontrivial spin topology, protecting them from disorder and thermal fluctuations, (2) small size and self-organization into dense lattices and (3) particle-like dynamics, manipulation and addressability. Using a novel materials architecture we developed recently, I will address quantifiable insights towards understanding skyrmion stability and dynamics, and directions for exploiting their properties in nanoscale devices at room temperature.
##### The Tuesday JFI Seminar

October 30, 2018
GCIS W301 | Tuesday, 4:00 pm

## Yizhi You, Princeton Center for Theoretical Physics

#### Fracton phase of matter: Lattice models, gauge theories and realizations

Fracton phase of matter shares many features of topological order, including long-range entangled ground states and non-trivial braiding statistics. At the same time, fracton phase contains subextensive ground-state degeneracy and the restricted mobility of quasiparticle which exclude itself from the TQFT paradigm. In this talk, I start from several fracton lattice models and demonstrate their relation with gauged subsystem symmetric SPT phase. Further, I will present a theoretical framework for higher Chern-Simons theory in 3D which realizes a deconfined U(1) fracton phase. In the end, I propose an experiment platform for realizing diverse fracton stabilizer codes based on interacting nanowires, which enables us to fabricate a zoology of fracton states and thus provides a powerful novel avenue to the realization of stable quantum memory and fault-tolerant quantum computing.

October 30, 2018
PRC 201 | Tuesday, 12:00 pm

## Professor Daniel Palanker, Department Ophthamology & Hansen Experimental Physics Laboratory, Stanford University

#### Photovoltaic Restoration of Sight in Retinal Degeneration

Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image-processing” inner retinal layers are relatively well preserved. Information can be reintroduced into the visual system using electrical stimulation of the surviving inner retinal neurons. Some electronic retinal prosthetic systems have been already approved for clinical use, but they provide low resolution and involve very difficult implantation procedures. We developed a photovoltaic subretinal prosthesis which converts light into pulsed electric current, stimulating the nearby inner retinal neurons. Visual information is projected onto the retina from video goggles using pulsed near- infrared (~880nm) light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity. Optical activation of the photovoltaic pixels allows scaling the implants to thousands of electrodes.

In preclinical studies, we found that prosthetic vision with subretinal implants preserves many features of natural vision, including flicker fusion at high
frequencies (>20 Hz), adaptation to static images, center-surround organization and non-linear summation of subunits in receptive fields, providing high spatial resolution. Initial results of the clinical trial with our implants (PRIMA, Pixium Vision) having 100µm pixels, as well as preclinical measurements, confirm that spatial resolution of prosthetic vision can reach the sampling density limit. For a broad acceptance of this technology by millions of patients who lost central vision due to age-related macular degeneration, visual acuity should exceed 20/100, which requires pixels smaller than 25µm. I will describe the fundamental limitations in electro-neural interfaces and 3-dimensional configurations which should enable such a high spatial resolution. Ease of implantation of these wireless modules, combined with high resolution opens the door to highly functional restoration of sight.
Host: Bozhi Tian, 2-8749 or via email at btian@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### Special JFI Seminar

October 29, 2018
GCIS W301 | Monday, 1:30 pm

## Professor Matthew Kanan, Stanford University

#### Re-sourcing Chemicals

This talk will describe our recent efforts to turn CO2 into a carbon source for commodity chemicals. Our goal is to develop scalable processes in which the use of CO2 affords a clear chemical advantage over conventional fossil fuel–based routes. I will first describe new carboxylation chemistry to generate (di)-carboxylic acids that have high-volume applications. Conventional carboxylation methodology relies on extremely energy-intensive reagents. We have found systems in which simple carbonate salts deprotonate un-activated C–H bonds, generating carbon-centered nucleophiles that react with CO2 to form C–C bonds. As one application, we used this chemistry to develop a high-yielding route from inedible biomass to furan-2,5-dicarboxylic acid (FDCA), a monomer that is currently being pursued as a replacement for terephthalic acid in polyester synthesis. To generalize this strategy, we have recently developed nanostructured carbonates that can perform hydrocarbon C–H insertion. In a two-step cycles, these materials convert arenes, CO2, and alcohols into aromatic esters with no use of stoichiometric reagents or generation of waste products. In the second part of my talk, I will describe our work on electrochemical systems for generating C2 feedstock chemicals. We have pioneered the use of grain boundaries to create metastable active surfaces for CO2 and CO reduction and recently elucidated a structural model to explain grain boundary effects. I will discuss the prospects for exploiting grain boundary effects in electrosynthesis and the design of prototype reactors that provide high synthesis rates and concentrated product streams.
##### Chemistry

October 29, 2018
Kent 120 | Monday, 1:15 pm

## Professor Jiaoyang Jiang, University of Wisconsin-Madison

#### Specificity, Function and Regulation of Protein O-GIcNAc Modification

The N-acetylglucosamine (O-GlcNAc) modification is an essential glycosylation that has been identified on over 1,000 proteins. It dynamically modulates protein functions and regulates numerous biological processes in physiology and disease. O-GlcNAc modification is added by O-GlcNAc transferase (OGT) and removed by O-GlcNAcase (OGA). Despite recent progress, challenges remain to decipher the biological roles of O-GlcNAc modification and its regulation by OGT and OGA on a broad range of substrates that lack an apparent sequence motif. In this talk, I will present our recently developed structural biology and chemical biology approaches to start revealing the specificity, function and regulation of O-GlcNAc modification.
##### Chemistry

October 26, 2018
Kent 120 | Friday, 1:15 pm

## William Irvine, University of Chicago

#### Spinning Top-ology

Geometry, topology and broken symmetry play a powerful role in determining the physics of materials. In this colloquium I will talk of activated materials and fluids built out of mechanically spinning components and show how the subtle interplay of structure, time-reversal and parity leads to `odd' solid and fluid mechanics. In particular I will discuss a simple kind of active meta-material – coupled gyroscopes – that naturally encodes non-trivial topology in its vibrational spectrum. In particular, I will show how topology can emerge not only in ordered gyro materials but also their amorphous counterparts. We will then foray into activated colloidal gyro fluids and see how breaking symmetry under parity leads to chiral surface states and odd instabilities driven by viscous forces. We will use these chiral waves as a tool to observe the presence of odd (or Hall) viscosity in our chiral fluid.
##### Physics Colloquium

October 25, 2018
KPTC 106 | Thursday, 4:00 pm

## Professor Marc Fontecave, Collège de France

#### FeS Clusters and Thiolation Reactions: Lessons from tRNA- and Protein-modifying Enzymes

Living cells are full of molecules containing sulfur atoms, for example biotin, lipoic acid, thiamin but also a variety of nucleosides within transfer RNAs and inorganic cofactors such as iron-sulfur (FeS) clusters. However, how these compounds are biosynthesized and how sulfur atoms are incorporated into organic substrates are still open fascinating questions. The discovery that important enzymes involved in thiolation reactions are FeS enzymes belonging to the Radical-SAM (S-Adenosyl-Methionine) enzyme superfamily, such as biotin synthase or lipoate synthase, has suggested a novel function for FeS clusters. It is proposed that they serve, in these enzymes, as a sulfur storage system from which sulfur atoms can be delivered to activated substrates during thiolation. The chemistry of Radical-SAM enzymes in the specific context of these reactions will thus be presented. However, other results, in particular from our laboratory, have challenged this theory since we have shown, during our functional and structural characterization of tRNA- and protein-sulfurating FeS enzymes (methylthiotransferases and thiolases) that thiolation can occur without mobilization of the sulfur atoms of the FeS clusters. Here we discuss these alternative mechanisms.
##### Chemistry

October 25, 2018
Kent 120 | Thursday, 1:15 pm

## Pedro Saenz, MIT

#### Spin lattices of walking droplets

Understanding the self-organization principles and collective dynamics of non-equilibrium matter remains a major challenge despite considerable progress over the last decade. In this talk, I will introduce a hydrodynamic analog system that allows us to investigate simultaneously the wave-mediated self-propulsion and interactions of effective spin degrees of freedom. Millimetric liquid droplets can walk across the surface of a vibrating fluid bath, self-propelled through a resonant interaction with their own guiding wave fields. A walking droplet, or ‘walker', may be trapped by a submerged circular well at the bottom of the fluid bath, leading to a clockwise or counter-clockwise angular motion centered at the well. When a collection of such wells is arranged in a 1D or 2D lattice geometry, a thin fluid layer between wells enables wave-mediated interactions between neighboring walkers. Through experiments and mathematical modeling, we demonstrate the spontaneous emergence of coherent droplet rotation dynamics for different types of lattices. For sufficiently strong pair-coupling, wave interactions between neighboring droplets may induce local spin flips leading to ferromagnetic or antiferromagnetic order. Transitions between these two forms of order can be controlled by tuning the lattice parameters. More generally, our results reveal a number of surprising parallels between the collective spin dynamics of wave-driven droplets and known phases of classical condensed matter systems. This suggests that our hydrodynamic analog system can be used to explore universal aspects of active matter and wave-mediated particle interactions, including spin-wave propagation and topologically protected dynamics far from equilibrium.
##### Computations in Science

October 24, 2018
KPTC 206 | Wednesday, 12:15 pm

#### Wilson Loops, Wyckoff Positions, and Wannier Functions: New Developments in Stable and Fragile Topology

The interplay of topology and geometry has been -- and continues to be -- a rich area of study for condensed matter physics. Recently, we have realized that spatial symmetries allow for the stabilization of topological phases much more exotic than those that can be found with time-reversal symmetry alone. Examples include topological crystalline insulators, "hourglass Fermion" phases, and Dirac and double-Weyl semimetals. In this talk, I will review recent developments in the theory of band representations which highlight the role of Wannier functions and holonomy in explaining the origins of topological crystalline behavior. I will show how this relates to several new ideas, such as symmetry indicators, topological phases with high co-dimension boundary states, and the "fragile" topology of isolated groups of bands. Finally, I will discuss how non-symmorphic symmetries can protect novel topological surface states, which can be diagnosed through the holonomy of Bloch functions.

October 24, 2018
PRC 201 | Wednesday, 11:00 am

## MRSEC Surface Metrology Workshop

#### in cooperation with Olympus

8:30 AM : Breakfast
9:00 AM: Introduction to LEXT OLS5000 Laser Confocal Microscope, Guangnan Meng, PhD
10:00 AM: Coffee Break
10:15 AM: MRSEC Student Talks: Applications
11:30 AM: A Few Things You Need to Know About Surface Roughness: Guangnan Meng, PhD
12:15 PM: Lunch (registration required)
1:00 PM - 5:00 PM: Sample Demonstrations and Discussions

https://www.surveymonkey.com/r/9QBQFRN
##### MRSEC Workshop

October 24, 2018
GCIS W301 | Wednesday, 9:00 am

## Prof. Michael Grünwald, Department of Chemistry, University of Utah

#### Orientational Order in Self-Assembled Nanocrystal Superlattices

Self-assembly of nanocrystals into functional materials requires precise control over nanoparticle interactions in solution, which are dominated by organic ligands that densely cover the surface of nanocrystals. In this talk, I will present a computational study of ligand effects in the self-assembly of small, non-spherical nanocrystals. We focus on nanocrystals with cuboctahedral and truncated octahedral shape and determine their self-assembly behavior as a function of ligand length and solvent quality. Our model, which is based on a coarse-grained description of ligands and a schematic representation of solvent effects, reproduces the experimentally observed superstructures, including recently observed superlattices with partial and short-ranged orientational alignment of nanocrystals. We show that small differences in nanoparticle shape, ligand length and coverage, and solvent conditions, can lead to markedly different self-assembled superstructures due to subtle changes in the free energetics of ligand interactions. Our results help explain the large variety of different reported superlattices self-assembled from seemingly similar particles and can serve as a guide for the targeted self-assembly of nanocrystal superstructures. Host: Suri Vaikuntanathan, 2-7256 or via email at svaikunt@uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The Tuesday JFI Seminar

October 23, 2018
GCIS W301 | Tuesday, 4:00 pm

## Professor Marc Fontecave, Collège de France

#### Carbon Dioxide to Fuels: from Enzymes to Bioinspired Catalysts

##### Chemistry

October 23, 2018
Kent 120 | Tuesday, 1:15 pm

## Yuhai Tu, PhD, IBM

#### Nonequilibrium physics in biochemical oscillations

A central problem in systems biology is how living systems manage to perform precise functions (development, replication, signaling, etc.) by using inherently noisy biochemical networks. What are the molecular mechanisms for control? What are the design principles for the underlying biochemical networks? What are the energy costs for regulation? In this talk, we will present some recent results to address these general questions in biochemical oscillatory systems. We will discuss the molecular mechanism and energy cost for enhancing the accuracy and synchronization of biochemical oscillators [1]; and the design principles for oscillatory biochemical networks to achieve both high entrainability and low phase fluctuations [2].
[1] “The free-energy cost of accurate biochemical oscillations”, Y. Cao, H. Wang, Q. Ouyang, and Yuhai Tu, Nature Physics, 11, 772, 2015.
[2] “Design principles for enhancing phase sensitivity and suppressing phase fluctuations simultaneously in biochemical oscillatory systems”, C. Fei, Y. Cao, Q. Ouyang, and Yuhai Tu, Nature Communications, doi:10.1038/s41467-018-03826-4, 2018.
##### Biophysical Dynamics

October 23, 2018
GCIS W301 | Tuesday, 12:00 pm

## Chemistry Colloquium: Professor Naoto Chatani, Osaka University

#### Development of New Catalytic Reactions Involving the Activation of Traditionally Inert Bonds

Organic molecules contain a variety of chemical bonds. Organic synthesis involves the cleavage of a chemical bond and the formation of a new chemical bond. However, not all of the chemical bonds in organic molecules have been used in organic synthesis. Thus, organic synthesis is heavily dependent on the reactivity of chemical bonds. If so-called unreactive bonds were to be used directly in organic synthesis, new possibilities for developing new synthetic methodologies would arise. We have utilized, not only the activation of C-H bonds, but also the activation of unreactive single bonds, such as C-C, C-O, C-N, and C-F bonds, and the activation of C-C triple bonds and C-O double bonds, in our quest to develop new types of transformations that will lead to further diversification in the field of organic synthesis.
##### Chemistry

October 22, 2018
Kent 120 | Monday, 4:00 pm

## Professor Michael J. Hatridge, Department of Physics, University of Pittsburgh

#### Qubit Measurement with Two-Mode Squeezed Light

High fidelity qubit measurement is essential for scalable, fault-tolerant quantum computing. In superconducting circuits, qubit readout with fidelity above 99% has been achieved by using a quantum-limited parametric amplifier such as the Josephson Parametric Converter (JPC) as the first stage amplifier. However, the Signal-to-Noise Ratio (SNR) of such readout is fundamentally limited by quantum fluctuations in the coherent readout pulse. Alternatively, readout with squeezed light can be used to reduce fluctuation along certain quadratures and thus improve the SNR. In this talk, we demonstrate a readout scheme with two-mode squeezed light both produced and amplified by JPCs in an interferometer unbalanced by a transmon qubit/cavity. This configuration has been predicted to improve the SNR compared to readout with both coherent states and single-mode squeezed light. We have demonstrated a 50% improvement in SNR compared to coherent state readout, and find that the system actual works best when when we deliberately break the path for signals in the system, so that only the fluctuations passing through it interfere. We'll also discuss the prospects for placing qubits on both arms of the interferometer and performing measurements which generate remote entanglement between them.
##### JFI Special Seminar

October 22, 2018
GCIS E223 | Monday, 3:30 pm

## Inorganic/Organic Seminar: Professor Hemamala Karunadasa, Stanford University

#### Between the Sheets: The Molecular Chemistry of Hybrid Perovskites

The tools of synthetic chemistry allow us to tune molecules with a level of precision not yet accessible with inorganic solids. We have investigated hybrid perovskites that couple organic small molecules with the optical and electronic diversity of extended inorganic solids. I will share our current understanding of these materials, whose technologically relevant properties are highly amenable to synthetic design.
The 3D lead-iodide perovskites have recently been identified as low-cost absorbers for high-efficiency solar cells. Although the efficiencies of devices with perovskite absorbers have risen at an impressive rate, the materials’ intrinsic instability and toxicity may impede their commercialization. I will discuss methods developed by our group to address these problems. The 2D hybrid perovskites have dramatically different properties from their 3D congeners. We discovered that some 2D perovskites emit broadband white light (similar to sunlight) when excited by UV light. I will discuss how these materials, which do not contain extrinsic dopants or obvious emissive sites, could emit every color of visible light. Although the organic molecules in hybrid perovskites have mostly played a templating role, we have investigated their role in engendering reactivity. I will describe reactions that occur between the inorganic sheets, which allow these nonporous solids to capture small molecules.
##### Chemistry

October 19, 2018
Kent 120 | Friday, 1:15 pm

## Can a large packing be assembled from smaller ones ?

Eat 12
##### MRSEC Baglunch

October 19, 2018
GCIS E123 | Friday, 12:00 pm

## Jean Dalibard, Collège de France

#### Exploring Flatland with cold atoms

The physics of many-body systems strongly depends on their dimensionality. For example, in a two-dimensional world, most standard phase transitions towards an ordered state of matter like crystals or magnets would not occur because of the increased role of fluctuations. However, non-conventional phase transitions can still take place, as understood by Kosterlitz and Thouless (2016 Nobel prize). In this talk I will present some important features of Flatland physics explored with cold atomic gases, such as the existence of a superfluid transition that occurs in the absence of Bose-Einstein condensation. I will also discuss out-of-equilibrium properties of these atomic 2D gases, in connection with the so-called Kibble-Zurek mechanism.
##### Physics Colloquium

October 18, 2018
KPTC 106 | Thursday, 4:00 pm

## IME Distinguished Colloquium Series - Prashant Kamat

Professor Prashant Kamat from University of Notre Dame will speak as part of the IME Distinguished Colloquium Series.

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

October 17, 2018
KCBD 1103 | Wednesday, 4:00 pm

## Peizhi Du, Maryland University

#### Hybird seesaw leptogenesis and TeV singlets

The appealing feature of inverse seesaw models is that the neutrino mass emerges from the exchange of TeV scale singlets with sizable Yukawa couplings, which can be tested at colliders. However, the tiny Majorana mass splitting between TeV singlets is left unexplained. Moreover, we argue that these models suffer from a structural limitation that prevents a successful thermal leptogenesis if Yukawa couplings are unsuppressed. In this talk, I will introduce a hybrid seesaw model, where we replace the mass splitting with a coupling to a high scale seesaw module including a TeV scalar. I will show that this structure achieves the goal of filling both the above gaps with couplings of order unity. The necessary structure automatically arises embedding the seesaw mechanism in composite Higgs models. Our hybrid seesaw models have an interesting interplay between high scale and TeV scale physics in leptogenesis and enlarges the range of allowed high scale singlet masses.
##### Theory Seminar

October 17, 2018
PRC 201 | Wednesday, 1:30 pm

## Andrew Ferguson, University of Chicago

#### Machine learning design of self-assembling colloidal crystals and inference of protein folding funnels

Data-driven modeling and machine learning have opened new paradigms and opportunities in the understanding and design of soft and biological materials. Colloidal particles with tunable anisotropic surface interactions are of technological interest in fabricating responsive actuators, biomimetic encapsulants, and photonic crystals with omnidirectional band gaps. In the first part of this talk, I will describe our applications of nonlinear manifold learning to determine low-dimensional assembly landscapes for self-assembling patchy colloids. These landscapes connect colloid architecture and prevailing conditions with emergent assembly behavior, and enable inverse building block design by rational sculpting of the landscape to engineer the stability and accessibility of desired aggregates. Rational engineering of structural and functional polymers and proteins requires an understanding of the underlying free energy landscapes dictating thermodynamic stability and kinetic folding pathways. In the second part of this talk, I will describe an approach integrating ideas from dynamical systems theory and nonlinear manifold learning to reconstruct multidimensional protein folding funnels from the time evolution of single experimentally-measurable observables.
##### Computations in Science

October 17, 2018
KPTC 206 | Wednesday, 12:15 pm

## Lee Lecture: Professor Susumu Kitagawa, Kyoto University

#### Chemistry and Application of Soft Porous PCP/MOF

e have found unique porous properties of PCPs/MOFs, which possess flexible or dynamic porous frameworks, reversibly responding to external stimuli, not only chemical but also physical. They were developed in an effort to realize dynamic porous and collective functionality not found in conventional materials. Their compositions of metal ions and organic molecules have achieved diversity in the electronic states. That is, the spatial and electronic structures can be altered, realizing magnetic and dielectric properties as well as oxidation− reduction functions. Besides normal storage, such MOFs have vast potential for separation with an extremely high selectivity, high-efficiency storage, and catalysis, as well as sensing and actuator functions. For these reasons, many studies investigate these materials. In this lecture, I discuss porous materials with capabilities that exceed current ones and the future research direction.
##### Chemistry

October 17, 2018
GCIS W301 | Wednesday, 12:00 pm

## Jessica M.J. Swanson, The University of Chicago

#### Unraveling Multistep Kinetic Mechanisms Behind Coupled Ion Exchange: A Case Study on Cl-/H+ Exchangein ClC Antiporters

Understanding complex mechanisms such as transmembrane ion exchange by proteins in molecular, thermodynamic, and kinetic detail remains a significant challenge. In this talk, I will present a new approach to integrate experimental and simulation data to fully characterize Cl–/H+ exchange in ClC antiporters. Rate coefficients are first calculated with reactive and polarizable molecular dynamics simulations and then optimized within a coupled kinetic (Markov state) model to reproduce experimental data. This produces a set of solutions that not only predict new properties but also reveal insight into the series of transitions that define the mechanism, the molecular origin of the unusual 2.2:1 Cl–/H+ stoichiometry, and the influence of protein orientation. I will explain how the consistent exchange ratio is a consequence of kinetic coupling and how the lack of large protein conformational changes suggests a more facile evolutionary connection between chloride channels and more evolved antiporters. Finally, I will discuss how an ensemble of different stochastic exchange pathways, as opposed to a single series of distinct transitions, culminates in the macroscopic observables and thereby helps to explain the underlying molecular mechanism.
##### Biophysical Dynamics

October 16, 2018
GCIS W301 | Tuesday, 12:00 pm

## Lee Lecture: Professor Susumu Kitagawa, Kyoto University

#### Porous Coordination Polymers/Metal Organic Frameworks

Permanent porosity for coordination networks in solids was discovered and demonstrated with gas sorption experiments (1997), whose materials are now known as porous coordination polymers (PCPs) or metal-organic frameworks (MOFs). They are an emerging class of microporous solids combining the modularity of inorganic structural building units (nodes) with organic ligands (linkers) that can be tailored through organic synthesis. This particular combination of designability and the structural porosity of MOFs has led to explosive growth in their application to gas storage/separation, catalysis, ion conductivity, chemical sensing, and drug delivery systems. To date, MOFs are classified as a new category of porous materials, as opposed to the conventional classifications of inorganic and carbon materials. Researchers in the world synthesized a wide variety of MOFs and developed the comprehensive structural chemistry. We have developed the chemistry of coordination space, focusing on functionalities, and discovered flexible MOFs (soft porous crystals) which to date are another dimension of porous materials.
MOFs have been extensively researched in both academia and industry. Industrial syntheses are rapidly advancing. Researchers in both academia and industry are producing MOFs materials for use in purification, storage, transportation, and conversion, vital to addressing energy and environmental issues and contributing to human welfare.
Persons with a disability may call (773) 795-5843 in advance for assistance.
##### Chemistry

October 15, 2018
Kent 120 | Monday, 4:00 pm

## Dr. Christa Flühmann, Department of Physics, ETH Zurich

#### An Encoded Qubit in a Trapped-ion Oscillator

I will present recent experiments demonstrating a qubit encoded in the harmonic motion of a single trapped 40Ca+ ion [1]. The usage of the oscillator allows to study a logical qubit with a single quantum system, while in contrast commonly used error-correction schemes are based on arrays of many physical qubits. The approximate logical code states are formed from a periodically spaced superposition of displaced squeezed components, which has theoretically been shown to have optimal performance for a large set of errors [2, 3]. Our first time demonstration of these qubits is based on coupling the ion motional oscillator to an internal state ancillary qubit, which we can subsequently readout. This indirect readout of the oscillator via the ancillary qubit we have previously interpreted as a modular position or momentum measurement and explored the relations between sequences of these measurements [4]. Such sequences allow us to create the logical codes states as well as measure their spatial and momentum probability densities, revealing the non-local features simultaneously present in both densities. Using the modular measurements we further implement logical state readout in the Pauli basis which we demonstrate on the six cardinal states of the Bloch sphere for which we reach an average square fidelity of 87.3 ± 0.7%. We implement the logical Pauli gates by displacements of the oscillator and realize arbitrary single qubit operations by modifying the modular measurements slightly. We analyze the performance of a universal single logical qubit gate set by performing process tomography, for Pauli gates we reach process fidelities of ≈ 97%, while for continuous rotations we achieve fidelities of ≈ 89%.
##### JFI Special Seminar

October 15, 2018
GCIS E223 | Monday, 3:30 pm

## MRSEC Lunch 'n Learn Workshop

#### HORIBA Duetta Fluorescence and Absorbance Spectrometer

Come see the worlds’ fastest 2 in 1 Fluorescence and Absorbance Spectrometer
Duetta
A Game Changing Spectrometer Concept
• UV-Vis-NIR Fluorescence Detection Wavelength Range from 250 to 1,100 nm
• Full 3-D Fluorescence EEM Acquisition in Less Than One Second
• Best in Class Fluorescence Sensitivity Specification of 6,000:1 RMS for Water Raman
• Automatic Correction for Primary
and Secondary Inner Filter Effects (IFE)
• High Fidelity Molecular Fingerprinting with Unique A-TEEMTM
(Absorbance-Transmittance Excitation Emission Matrix) Technology
• Millisecond CCD Detection of Entire Fluorescence Spectrum
##### MRSEC Workshop

October 12, 2018
ERC 301B | Friday, 11:30 am

## Stephan Meyer

#### Equity, Diversity and Inclusion

##### Physics Colloquium

October 11, 2018
KPTC 106 | Thursday, 4:00 pm

## Paul Oehlmann, Virgina Tech

#### Gauged Superconformal matter from exotic F-theory fibrations

We consider 6 dimensional supergravity theories coupled to gauged superconformal matter. The physics is extracted from F-theory on smooth torus fibered Calabi-Yau threefolds. The superconformal matter resides at points in the base of the fibration that are either smooth, in the case of (1,0) superconformal matter, or orbifold singularities in the (2,0) case.
Smoothness of the the full geometry implies exotic fiber behavior over those points
such as non-flat and multiple fibers that we analyze in detail. The topology of those
fibers and the full geometry allows an interpretation for the superconformal matter which
can be verified by analyzing their deformation spaces.
##### Theory Seminar

October 10, 2018
PRC 201 | Wednesday, 1:30 pm

## Shinsei Ryu, University of Chicago

#### Topology and entanglement detected by partial transpose

Quantum many-body systems exhibit very rich phenomena unexpected from their classical counterparts. In this talk, I will focus on a quantum information theoretical operation -- partial transpose -- which is useful in detecting quantum entanglement. I will describe how partial transpose can be used to detect topology and entanglement in quantum many-body systems, ranging from topological phases of condensed matter to systems which have holographic dual descriptions. In particular, I will describe the constructions of topological invariants using partial transpose, and possible holographic dual objects corresponding to entanglement negativity, which is an quantum entanglement measure constructed by using partial transpose.
##### Computations in Science

October 10, 2018
KPTC 206 | Wednesday, 12:15 pm

## Omrie Ovdat, Technion

#### Vacancies in Graphene: Dirac Physics and Fractional Vacuum Charges

Significant interest has lately been devoted to the study of vacancies in graphene obtained by removing a neutral carbon atom. The presence of a single vacancy has interesting and unexpected consequences. It leads to the occurrence of a stable charge of order unity localized at the vacancy site and interacting with other charges of the conductor by means of an Coulomb potential. It also breaks the symmetry between the two triangular graphene sublattices hence inducing zero energy states at the Dirac point. These features have been noticed, however, their precise underlying mechanism and its relation to Dirac physics, if any, are yet to be investigated. Here we show the fractional and pseudo-scalar nature of this stable vacancy charge originating from the vacuum and insensitive to screening effects. A continuous Dirac model is presented which relates zero modes to vacuum fractional charge and to parity symmetry breaking. This relation, constitutes an Index theorem and is achieved by using particular chiral boundary conditions, which map the vacancy problem onto edge state physics and link zero energy states to topological features of the bulk alike the Hall effect or physics of kinks, vortices and monopoles. Vacancies in graphene thus allow to realize prominent features of $2+1$ quantum electrodynamics, e.g., charge fractionalization and parity breaking, but without coupling to a gauge field.This essential difference makes vacancy physics relatively easy to implement and an interesting playground for topological charge switching.

October 9, 2018
PRC 201 | Tuesday, 4:00 pm

## JFI Tuesday Seminar - Prof. Jean Dalibard - College de France

#### Topological Protection in Quantum Gases

How can one classify the states of matter? Beyond well-known
arguments based on geometrical symmetries, the application of concepts
originating from topology is currently leading to fascinating
developments. These concepts were initially proposed in condensed matter
physics in order to describe the Quantum Hall effect, and they are now
spreading over many fields of research, notably in atomic physics and
optics. In this lecture, I will present some robust properties that
characterize topological matter formed with atomic gases, which persist
when one modifies the system parameters or add some disorder. I will
also explain how these concepts can lead to novel devices that take
advantage of topological robustness. Host: Cheng Chin, 2-7192 or via email to cchin@jfi.uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The Tuesday JFI Seminar

October 9, 2018
GCIS W301 | Tuesday, 4:00 pm

## Nathan Seiberg, IAS

#### Recent advances in 2+1d QFT

We will review recent developments in the study of quantum field theory in 2+1 dimensions. Newly discovered subtleties in the analysis of the short distance behavior of these theories have uncovered surprising properties. They help motivate a rich web of conjectures about the long distance behavior of these systems. These conjectures describe new phases and new phase transitions between them. Also, in many cases these transitions have several different dual descriptions. These new developments were motivated by ideas in high energy physics, string theory, and condensed matter physics. And they have potential applications in these fields.

October 9, 2018
PRC 215 | Tuesday, 1:30 pm

## Chemistry Colloquium: Professor Masaru Kuno, University of Notre Dame

#### Single Semiconductor Nanostructure Extinction Spectroscopy

There has been thirty years of emission-based single particle microscopy and spectroscopy since Moerner’s seminal single molecule study. While highly successful in revealing the properties of matter hidden by ensemble averages, the limits of emission-based microscopies have now become apparent. To address recognized future needs and, in particular, the need to go beyond fluorescent specimens, single particle extinction techniques have been developed. Motivating this has been the desire to acquire information about the electronic structure of nanoscale materials difficult to obtain otherwise using either ensemble or emission-based single particle measurements. Circumstances where single particle extinction measurements offer superior alternatives to traditional microscopies/spectroscopies include situations where the material of interest is non-emissive or where current syntheses yield ensembles with large size and/or compositional distributions that hide the underlying spectral response of a material. Most relevant, though, are cases where information about the underlying electronic structure of a material -something directly encoded in its absorption- is less forthcoming and is at best inferred indirectly using emission-based approaches.
This talk describes the inherent problems associated with measuring the extinction of low dimensional semiconductors. It simultaneously describes the fundamental operating principles of two common extinction techniques while highlighting their achievements. It then reviews what exactly we have learned about the fundamental physics of CdSe, a model semiconductor nanosystem. The talk ends by describing the future development of new single particle extinction methodologies such as infrared photothermal heterodyne imaging.
##### Chemistry

October 8, 2018
Kent 120 | Monday, 4:00 pm

## Inorganic/Organic Seminar: Professor Keary Mark Engle, The Scripps Research Institute

#### Catalytic Methods for Selective Functionalization of C–C π-Bonds

Vicinal (1,2-disubstituted) functional group motifs are ubiquitous in structurally complex small molecules that are of academic and industrial importance, including many widely used pharmaceutical agents. Many such functional group combinations, however, remain exceptionally challenging to synthesize. The goal of research in the Engle lab is to develop a general catalytic platform for alkene and alkyne difunctionalization to introduce a diverse array of functional groups at each of the two carbon atoms in a programmable fashion. Our central hypothesis is that is that coordination of a π-Lewis acidic metal, such as palladium(II), to the alkene will promote nucleophilic attack and that the resultant organometallic species can be trapped with an electrophile to furnish the desired 1,2-difunctionalized product. In the overall net transformation, one of the two new functional groups is introduced in the form of a nucleophile, and the other in the form of an electrophile. Directing groups are used to control the regiochemical course of the reaction and stabilize key alkylmetal intermediates. These concepts have been used to expand the synthetic toolkit to include new retrosynthetic disconnections, including “homo-Michael” addition and β,γ-vicinal dicarbofunctionalization of alkenyl carbonyl compounds.
##### Chemistry

October 5, 2018
Kent 120 | Friday, 1:15 pm

## David Schimitz, University of Chicago

#### Neutrino Physics at Long and Short Baselines: The DUNE and SBN Experiments at Fermilab

The study of neutrinos over the past 60 years has revealed an incredible amount about the Standard Model of elementary particles, despite neutrinos being one of the most challenging areas of exploration in particle physics. This combination, a seeming contradiction, motivates continued experimental effort at a grand scale to reveal the neutrinos’ further secrets. One of the global centers of neutrino physics research is at Fermilab, forty miles west of campus, which hosts the future Deep Underground Neutrino Experiment, DUNE, and the ongoing Short-Baseline Neutrino experiment, SBN. In this talk, I will review some of the biggest past discoveries in neutrino physics and preview the exciting future ahead with these new experiments at unprecedented scales and with world-leading reach for new discoveries.
##### Physics Colloquium

October 4, 2018
KPTC 106 | Thursday, 4:00 pm

## Xiao Chen, KITP, UC Santa Barbara

#### Operator dynamics and quantum chaos: an approach from Brownian circuit

Operator scrambling is a crucial ingredient of quantum chaos. Specifically, in the quantum chaotic system, a simple operator can become increasingly complicated under unitary time evolution. This can be diagnosed by various measures such as square of the commutator (out-of-time-ordered correlator), operator entanglement entropy etc. In this talk, we discuss operator dynamics in three representative models: a 2-local spin model with all-to-all interaction, a chaotic spin chain with long-range interactions, and the quantum linear map. In the first two examples, we explore the operator dynamics by using the quantum Brownian circuit approach and transform the operator spreading into a classical stochastic problem. Although the speeds of scrambling are quite different, a simple operator can eventually approach a "highly entangled" operator with operator entanglement entropy taking a volume law value (close to the Page value). Meanwhile, the spectrum of the operator reduced density matrix develops a universal spectral correlation which can be characterized by the Wishart random matrix ensemble. In contrast, in the third example (the quantum linear map), although the square of commutator can increase exponentially with time, a simple operator does not scramble but performs chaotic motion in the operator basis space determined by the classical linear map. We show that once we modify the quantum linear map such that operator can mix in the operator basis, the operator entanglement entropy can grow and eventually saturate to its Page value, thus making it a truly quantum chaotic model.

October 4, 2018
PRC 215 | Thursday, 2:30 pm

## Special Seminar: Professor Li Deng, Brandeis University / Westlake University

#### Activation of Nucleophiles for Asymmetric Reaction with Organic Molecules

Organic molecule-mediated selective catalysis (i.e. selective organocatalysis) has evolved into a generally applicable, powerful strategy for asymmetric synthesis over the past few years. This lecture will present synthetic and mechanistic studies focusing on the development of weak-bonding organocatalysis directed towards the activation of nucleophiles for realizing asymmetric transformations of synthetic importance.
##### Chemistry

October 4, 2018
GCIS W301 | Thursday, 2:30 pm

## Marija Vucelja, University of Virginia

#### Adaptation of a bacterial population and the adaptive immune system of bacteria with CRISPR

The CRISPR (clustered regularly interspaced short palindromic repeats) mechanism allows bacteria to defend adaptively against phages and other invading genomic material. The CRISPR machinery acquires short genomic sequences from the "invaders" and in this way builds up a memory of past infections. With a new encounter of an invading sequence, this memory is accessed, and in a successful outcome, the invader is neutralized. I will introduce a population dynamics model where immunity can be both acquired and lost. I will describe the predictions of this model and suggest experiments.

Adaptation, where a population evolves increasing _x000C_fitness in a fixed environment is often thought of as a hill climbing process on a _x000C_fitness landscape. With a fi_x000C_nite genome, such a process eventually leads the population to a _x000C_fitness peak, at which point _x000C_fitness can no longer increase through individual beneficial mutations. Instead, the ruggedness of typical landscapes due to epistasis between genes or DNA sites suggests that the accumulation of multiple mutations can allow the population to continue increasing in _x000C_fitness. By using a spin-glass type model for the _x000C_fitness function that takes into account microscopic epistasis, we _x000C_find that hopping between metastable states can mechanistically and robustly give rise to a slow, logarithmic average _x000C_fitness trajectory.
##### Computations in Science

October 3, 2018
KPTC 206 | Wednesday, 12:15 pm

## IME Distinguished Colloquium Series - Arup Chakraborty

Professor Arup Chakraborty from Massachusetts Institute of Technology will kick off the IME Distinguished Colloquium Series with an hour-long talk.
##### Molecular Engineering

October 3, 2018
ERC 161 | Wednesday, 11:00 am

## 1st Tuesday Colloquium - Prof. David DeMille, Yale University

#### Diatomic Molecules as Quantum Tools

Our group is pursuing a wide range of physics goals, by applying techniques of modern atomic physics to the more complex system of diatomic molecules. For example, we use the strong electric field inside a polar molecule to amplify the observable effect from an electric dipole moment (EDM) of the electron, a CP-violating effect predicted in many extensions to the Standard Model of particle physics. We recently set a new upper limit on the electron EDM, placing severe bounds on many models of new physics at the TeV energy scale. In parallel, our group has developed the first methods for laser cooling and trapping of molecules. These techniques will enable interesting new frontiers in quantum many-body physics and quantum chemistry, as well as next-generation EDM searches. Host: Cheng Chin, 2-7192 or via email to cchin@jfi.uchicago.edu. Persons with a disability who may need assistance please contact Brenda Thomas at 2-7156 or by email at bthomas@uchicago.edu.
##### The 1st Tuesday JFI Colloquium

October 2, 2018
GCIS W301 | Tuesday, 4:00 pm

## Tobias Walther, PhD, Harvard

#### The Phase of Fat: Mechanisms & Physiology of Lipid Storage

##### Biophysical Dynamics

October 2, 2018
GCIS W301 | Tuesday, 12:00 pm