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Home , Angela Olinto, Emil Martinec, Enrico Fermi Institute, James Franck, James Franck Institute, Peter Freund

CHICAGO 2 Tied in Knots Welcome to the second issue of Physics! This past year has been an eventful one for our Department.

In our last issue, we discussed the series of public events that were being planned to commemorate and discuss Chicago Pile-1 and the complex legacy of what transpired on December 2, 1942. Over the course of that commemoration, many aspects were discussed in front of a large and interested audience.

On a separate front, we opened the renovated Physics Research Center, which is new home to the Institute, founded shortly after World War II to pursue experimental and theoretical research in high-energy , , plasma physics and other fields; and to the Kadanoff Center for , which brings together theorists across disciplines, from condensed matter physics to theory and hydrodynamics. We hope that many of you will come back to campus to visit these wonderful new facilities.

Of course, over the past year, our Department members continued to pursue outstanding research questions. You will learn about some of their successes in this annual newsletter. We hope that the stories we share will inspire you to become more involved and engaged in the Department. Please keep in touch and let us know what you think.

Yours sincerely,

YOUNG-KEE KIM Louis Block Distinguished Service Professor Chair, the Department of Physics

COVER PHOTO: WILLIAM IRVINE, Associate Professor Department of Physics, the CHICAGO PHYSICS 2 / TIED IN KNOTS

Contents

This issue of Chicago Physics 2 has been put together by a Knotted Vortices 6 number of us in the hope that it is of interest to those who have William Irvine brushed against the Physics Department in the University Topological Materials Made of Light 8 of Chicago. Jon Simon

Issues should have issues, and this issue is topology. Puzzle rings pave the way for stable quantum computers 10 Shinsei Ryu Topology is that annoying mathematical Jon Simon. Here he explains the generation topic which tries to convince you that a donut and uses of “twisted light.” Of course theorists Topology in 12 and a coffee cup are somehow equivalent. It like invariances, and topology is great for Emil Martinec turns out that this apparently arcane subject this—you simply need to know how to count. Materials Science at UChicago 14 has invaded physics recently in several very A candidate for a ‘theory of everything’ would Eileen Sheu & Margaret Gardel different fields, and because a few of our surely be one that depended on mathematics faculty are leading research in this area, we alone, no “fundamental” constants provided. New Faculty Spotlight 16 have selected some research highlights to The current incarnation of that is string theory, Vincenzo Vitelli explain what is happening. and Emil Martinec explains how our modern understanding of quantum topology is driving We are used to the idea that classical physics Student Voices 18 that theory forward. Clare Singer; Katrina Miller is local—forces are applied and responses are felt in the same region of space. But every These four articles cover some of the breadth Prizes & Awards 20 sailor understands the concept of a knot—a of what we do—quite literally from the distortion in the fabric of space which is not nanoscale to the cosmic scale—but also the Alumni Reflection 21 simply connected. William Irvine explains here unity of our subject in terms of the concepts how to build knots out of fluids, even when that drive us all. Another reminder of our Recent Happenings 22 the starting condition is that knottiness = zero. inclusivity is provided by Margaret Gardel, writing here as director of the MRSEC has no pretention to (Materials Research Science and Engineering Events 24 locality, though this remains one of its oddest Center) that crosscuts from materials to features. One remarkable discovery of recent biology to engineering, and has been Development 25 years is that the quantum numbers in which operating in Chicago under different guises some otherwise uninteresting solids live, in for several decades. Also here are some In Memorium 26 comparison to the boring vacuum outside pieces by a few of our students, who remain them, has a winding number (like the index of as intense, fascinating, and creative as any your mug). That means that some materials teacher could wish. As well as a calendar of automatically have a quantized current activities, and a reminder that all are welcome flowing over their surface. We hear about to our events. this from Shinsei Ryu, and in particular how this absurd effect might provide the basis We also celebrate here the lives of James for decoherence-free quantum computation, Cronin, Dean Eastman, Peter Freund, something that was brought to light by our Hellmut Fritzsche and Leon Lederman who own Woowon Kang in experiments on the died this year and left indelible imprints quantum Hall effects. It turns out that one in Chicago and globally. We miss them, and can build analogs of such systems with light, we are proud of them. using engineering as pioneered by - Peter Littlewood CHICAGO PHYSICS 2 / TIED IN KNOTS

Knotted Vortices

WILLIAM IRVINE

Conservation laws, such as conservation of energy, underpin our helicity is transferred from “link” to “writhe.” most fundamental understanding of physical phenomena. The This resolves one of the central issues of the large scale theory of turbulent fluids (which equations of fluid motion are a prime example: themselves an have widely distributed vorticity)—that expression of conservation of momentum, mass and energy, they reconnection does not necessarily destroy capture the myriad of fluid motions we see in the world. One of helicity. Careful studies of the dynamics of the cores have in fact demonstrated an apparently the most familiar examples of these structures is the hydrodynamic paradoxical result—that the action of viscosity vortex­—and even in real fluids with viscosity, vorticity is nearly can be to create helicity. The reason for this Figure 2 conserved. But it was only in 1961 that Moreau showed that within is that twist is a local contribution to helicity (and therefore can dissipate readily) whereas the Euler equations of fluid motion there lurked an additional writhe and link helicity are topologically conservation law­—that of hydrodynamic helicity, which counts the “Careful studies of the dynamics of the cores have in protected because they are non-local. linking of vortex lines. This is illustrated in Figure 1­—the linked vortex fact demonstrated an apparently paradoxical result— Quantities that are “conserved,” or stay lines on the right carry helicity, whereas the unlinked vortices do not. constant in time, “give you powerful ways to that the action of viscosity can be to create helicity.” look at complicated problems,” Irvine explains. “Understanding a new conserved quantity, thermonuclear fusion in the laboratory, an infinitely thin line, but can be thought of helicity, could have a huge impact on how we superfluids, and the solar corona. Or indeed as a braid of yarn (see Fig 3), and the helicity understand flows. It’s one of those holy grails.” Since vortices are transported by the velocity more practically the design of more efficient of two reconnecting loops can be separated field, in an ideal Eulerian fluid, they do not wind turbines or aircraft wings. But the into “link” helicity (left), “writhe” (center) cross. This means that in principle one understanding of the reconnection process and “twist” (right). Remarkably, when for should be able to construct knots in vortices has been largely theoretical until now. example two loops reconnect into one, the which would have a permanent existence Figure 1 in an ideal fluid. William Irvine’s lab has used numerical modelling and additive manufacturing to As a concept this goes back to Lord Kelvin, persisted in fluid mechanics and is now central construct flows that realized knotted vortices who proposed in 1869 that could be to our understanding of turbulent fluids. with helicity in water, for example the trefoil interpreted as knotted vortices in the ether, at knot (Kelvin’s simplest “”) and the linked the time believed to be an invisible fluid that In a viscous fluid, vortices can “reconnect”— vortex loops in Figure 2. filled all of space. The existence of the ether cross and separate—and understanding this was discredited theoretically by Maxwell and process is a key to modelling processes such Of course, these knots do rapidly reconnect, most famously experimentally by Michelson as turbulence in the earth’s atmosphere, but it turns out that careful inspection shows and Morley in 1887, but Kelvin’s intuition has the generation of the earth’s magnetic field, that the helicity remains. A real vortex is not Figure 3

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Topological Materials Made of Light

JON SIMON “To our surprise, we discovered that these Topology is the study of global properties that are insensitive to magic of synthetic materials: what’s exotic massive, charged We are now harnessing these colliding, local deformations. It has recently become pivotal in developing for traditional (electronic) materials is often twisting to explore topological natural for synthetic materials, and vice-versa. photons naturally act quantum fluids, writhing froths of entangled the understanding of a new class of materials whose electrical light whose excitations have been proposed To explore the black-hole physics of properties are robust to material imperfections (they are said to like they live on a as the bits of a quantum computing. This new using these photons, we have developed frontier in quantum science takes inspiration be “quantized’’). These materials provide a high-quality resistance a scanning-tunneling microscope for light. curved surface— from electrons in magnetic fields: we expect The results, shown in Fig. 1, reflect the standard and presenting a new topological route to error-resilient that working with photons will bring many enhanced density near the curvature—the first such is the magic of quantum computing. exciting surprises to light. experimental validation in any platform that synthetic materials: curvature acts like a magnetic field. It is becoming apparent that these topological explore their unique properties. We have what’s exotic for materials are in fact robust to a broader recently developed photonic topological In separate works we have also taught range of deformations than was previously materials and have found that photons in the photons to collide with one another and even traditional (electronic) understood and that they can be categorized lab quite naturally behave like electrons near crystallize, quite a challenge since we do not by different quantized responses to different curvature! In short, we have the opportunity to live in a world where photons naturally bounce materials is often natural deformations—for example a quantized explore the behaviours of electrons near black off one another like Star Wars lightsabers. for synthetic materials, heat conductivity reflects the “central holes using analogs made of photons. charge” of the material. Most interestingly and vice-versa.” To make this happen, we have learned a lot for our purposes is that some of the required about photons, and have taught photons “deformations” cannot be realized in the a few things along the way: (1) by trapping laboratory: it was predicted, for example, that photons between precisely spaced, high- electrons bunch-up in a quantized way around quality optical mirrors we trained them to the spatial curvature created by a massive have mass- that is, a transverse speed that object like a . The basic idea is that depends upon their momentum; (2) by under the right conditions, surface curvature trapping the photons between four mirrors can act to effectively increase the local instead of two, we add a twist to the photons’ magnetic field strength, shrinking particle back-and-forth motion, thus training them orbits, thereby increasing particle density. to behave as charged particles in magnetic In the Simon Lab at the University of Chicago, fields. To our surprise, we discovered that we make materials out light—photons instead these massive, charged photons naturally act of electrons, protons and neutrons—and like they live on a curved surface—such is the Figure 1 Photonic density of states measured for photons residing in the lowest Landau level of a cone; the enhanced density near the cone tip is the first experimental observation of the “Wen-Zee Shift,’’ where the curvature of a surface can act like a magnetic field.

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Puzzle rings pave the way for stable quantum computers

SHINSEI RYU

Figure 1 “Quantum states and processes used in quantum computers can be easily damaged or destroyed Have you ever tried a puzzle ring? Typically, it consists of a few understanding of underlying physics, the by noises and errors. If we don’t protect them in some metallic parts which are tangled together. You are supposed to probability for such errors to occur can be made sufficiently small—just like crafting very way, we cannot do anything useful.” disentangle these parts without breaking them. A typical example difficult puzzle rings! (Puzzle rings which looks like Figure 1. cannot be solved at all are rather boring— challenging with these puzzles, you may lose phases can be realized in condensed matter which cannot be untangled are said to be You may be surprised to know that certain types of quantum your friends if you don’t tell them that they systems at very low temperatures or topologically distinct from those which can computers use the idea rooted in puzzle rings. are actually not possible to untangle! On the can be engineered in systems consisting of be untangled. Similarly, quantum processes in other hand, they are perfect to realize stable many qubits. topologically ordered phases can be studied quantum computers.) by using topology. The key word common to puzzle rings and Quantum computers are a recently very operate at very low temperatures. It’s been Presented here is the scheme of a version topological quantum computers is topology. Even besides quantum computers, topology hot topic. Academics, as well as many private also challenging to build a quantum computer of quantum computers—topological quantum Topology is a subfield of mathematics which has been recently recognized as a governing companies, are putting a lot of efforts which can handle a large number of qubits computers—which make use of a special deals with properties of geometrical objects principle of quantum condensed matter (and money too) to realize them. Contrasting (quantum mechanical analog of bits). kind of states of matter—topologically ordered (lines, surfaces, hypersurfaces, etc.), which physics—a subfield of physics which deals to conventional computers (“classical” How can puzzle rings solve the problem of states of matter—which host special kinds are stable against under deformations. Puzzle with different states of matter consisting of a computers), the operating principle of quantum computers? Putting all details aside, of particles (anyons). Topologically ordered rings can be studied using topology—those macroscopic number of quantum mechanical quantum computers is quantum mechanics, for a certain type of quantum computer, it particles, such as electrons in solids. which governs physics at atomic scales. is possible to represent quantum processes Researchers have started to realize that, just They are expected to have many advantages in terms of a set of diagrams. A typical like we make a distinction between different over classical computers. For example, diagram may look like Figure 2. There, a set spaces/surfaces in terms of the loose criterion they are expected to be more powerful in of special particle—so-called anyons—are of topology, different states of matter can solving certain problems, e.g., decrypting created (marked by stars in Figure 2), and then be distinguished by different topologies secret messages (codes), and can be a manipulated, and finally measured. of wave functions. Quite a few in the game changer. condensed matter physics community, even Now, processes which are stable are those A crucial question to have successful quantum here at UChicago (including me), now use this which are not easy to untangle. In fact, ideal computers is stability—quantum computers new paradigm to study and explore phases of quantum processes, namely, processes are known to be much more difficult to realize matter, expecting that many new fundamental which are absolutely stable, correspond to than classical computers. Quantum states phenomena are yet to be discovered—we puzzles which cannot be untangled at all. and processes used in quantum computers hope you’ll be looking forward to them! Actual quantum processes can sometimes can be easily damaged or destroyed by be “untangled” (i.e., fail to operate properly). noises and errors. If we don’t protect them in However, researchers believe that, by some way, we cannot do anything useful. For improving technologies and deepening our these reasons, quantum computers usually

Figure 2

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Topology in String Theory

EMIL MARTINEC

Progress in theoretical physics has always gone hand in hand special class of black holes in string theory. with progress in mathematics, from Newton’s development of Remarkably, their answer relied in an essential way on the topology of “extra dimensions” calculus to formulate classical mechanics, to Einstein’s discovery in string theory. It had been something of that gravity is fundamentally related to the curvature of spacetime, an embarrassment that the cancellation to Heisenberg’s realization that linear algebra underlies quantum of anomalies in string theory requires that there be six or seven additional dimensions mechanics. In myriad ways, string theory represents the apotheosis of space, beyond the three that are readily

of this intellectual symbiosis, no more so than in the area of apparent in the world around us. In order to Figure 1 topology. Indeed, the resurgence of string theory in 1984 was be compatible with observation, these extra dimensions must be extraordinarily small; sparked by the demonstration that string theory was free from but they still have structure. Strominger the entropy indicates a quantum origin of in condensed matter physics, a topic where “anomalies”—potential topological obstructions to its mathematical and Vafa showed that, supposing the black the black hole microstates, and there is topology also plays an integral role. hole is merely a large object built out of the some evidence that the way string theory self-consistency. Topology is ubiquitous in string theory, and a key This convergence is an exciting trend of fundamental constituents of string theory— resolves certain puzzles about black hole mathematical tool to gaining insight into its properties. current research in theoretical physics, holding strings, membranes, etc.—that the number thermodynamics is by creating structures that out the hope that progress in either area can of ways that one could wrap those extended are quantum-mechanically coherent over A prime example comes from the For over two decades, the origin of black drive progress in the other. A central aim objects around the topology of the extra the horizon scale (that’s about 1km for a solar investigation of black holes in Einstein’s theory hole entropy remained a mystery. Then in of our new Kadanoff Center for Theoretical dimensions precisely accounts for the black mass black hole!). We are starting to see of gravity. Jacob Bekenstein and Stephen 1996, Andrew Strominger and Cumrun Vafa Physics is to provide a forum for the exchange hole entropy. Tiny extra dimensions (and their hints of what these structures are, and are Hawking showed in the early 1970’s that a showed how to compute the entropy of a of ideas and to foster cross-disciplinary intricate topology) turn out to be necessary investigating their properties using a variety black hole has an enormous thermodynamic collaborations, and I am eager to see what the ingredients to explain the internal states of of techniques in geometry, topology and entropy, proportional to the area of its event future brings. these particular black holes. string theory. horizon in so-called Planck units. For instance, “Tiny extra dimensions a black hole the mass of the Sun would (and their intricate In many ways, we are still coming to grips The information about what formed the black have an entropy 1077, some twenty orders of with the implications of this landmark result. hole, or later fell into it, is thought to be stored magnitude larger than the entropy of the Sun topology) turn out to be The topological nature of their computation in these diffuse, extended structures, and itself. This entropy is a measure of the number left unanswered precisely where the internal later radiated out via the thermal processes of internal states available to the black hole, necessary ingredients states of the black hole are supported— known as Hawking radiation. There are many yet provides no explanation to explain the internal is it at the horizon? At the singularity? similarities between this diffuse storage of what this state space might consist of; in And how does string theory evade the “no- quantum information by exotic “stringy” fact, quite the opposite—there are “no-hair” states of these particular hair” theorems of Einstein’s gravity? My own matter in the context of black holes, and theorems positing that the black hole solution research aims to answer these questions. the way quantum information is stored in to Einstein’s equations is unique. black holes.” The appearance of Planck’s constant ℏ in exotic quantum materials being explored

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Materials Science at UChicago

EILEEN SHEU & MARGARET GARDEL

Figure 3

If you’ve ever wandered through the Institute, you materials is that they contain distributed to create novel molecular assemblies for Chin and Levin explored non-equilibrium might overhear a number of conversations on scientific issues or molecular elements that convert chemical robust tunable shape change. Success of behavior of ultracold atom gases, resulting in energy into mechanical work, and a central the IRG would result in the identification of matter wave “jets” (Figure 3). engage in one yourself. The often-spectacular research that results question this IRG seeks to address is how such minimal combinations of elements capable of In addition to its research activities, the from this intensely interactive environment is partially credited activity relates to specific materials properties. programmable amorphous shape changes, MRSEC operates 10 Shared Facilities that To this end, Physics faculty Margaret Gardel, autonomous movement and collective to the research flexibility enabled through block funding by the provide vital support for research. The William Irvine, Vincenzo Vitelli and Tom behavior, and materials that could be tailored National Science Foundation (NSF). Originally initiated as an IDL MRSEC also participates in the Materials Witten collaborate with Chemists (Aaron to environments and situations beyond the Research Facilities Network (https://mrfn. (Inter-Disciplinary Laboratory) in 1961, the award transitioned Dinner, Norbert Scherer, Bozhi Tian, Suri reach of biological systems. Recently, using org) which provides access to the facilities to a MRL (Materials Research Laboratory), then into its current Vaikunathan, Gregory Voth and Lupin Yu) and these approaches William Irvine and Vincenzo for researchers from outside the University of Cell Biologist (David Kovar) to construct novel Vitelli demonstrated a new type of active configuration as a Materials Research Science and Engineering Chicago. MRSEC educational programs target active matter. This IRG aspires to achieve materials construct from a large collection of Figure 1 the research community with specialized Center (MRSEC). Through this award, the NSF mandates not only control of active materials and ultimately rotating magnets. workshops and exceptional training, and the highest-caliber multidisciplinary collaborative research, but also IRG 3 on Engineering Quantum Materials and our local neighborhood through science properties in the bulk and, conversely, how requires the incorporation of underrepresented groups into the Interactions seeks to elucidate the critical enrichment opportunities. We run research tailoring bulk parameters can guide interfacial research mission, maintaining shared facilities, educational outreach issues of control and coherence in both experiences programs for undergraduates dynamics, the research endeavors to establish individual and in collective-mode quantum and high school students. Our annual physics to the public, and knowledge transfer to industry, thus adding value the link between processes occurring at the systems, with the goal of manipulating and show and open house for the public brings interface and the properties of the material to the scientific enterprise of the Center and impelling researchers exploiting quantum coherence in materials in visitors who may have never previously as a whole. Establishing such a link opens up to adopt a broader outlook. over a large range of length scales, from talked to a scientist. Research-related exhibits opportunities for designing specific material individual quantum centers to macroscopically are developed in collaboration with the responses and provides a pathway towards controlling and manipulating how fast and to entangled materials. This research is Museum of Science and Industry (Chicago) In its current configuration, the MRSEC innovative applications. One thrust is to create what extent a soft interface forms or deforms. expected to directly advance applications and the Exploratorium (San Francisco). involves the work of around 40 investigators, materials with a mechanical response that Here Physics faculty Heinrich Jaeger, Arvind in quantum sensing, fabricate materials for Knowledge transfer activities engage industry their postdocs and students, and is overseen varies as a function of applied stress. To this Murugan, Sid Nagel, Vincenzo Vitelli and Tom quantum information as well as create the in collaborative research, and provide students by the Director, Prof. Margaret Gardel. The end, IRG 1 developed a new design platform of Witten team with faculty from Chemistry next generation of characterization tools for with opportunities to experience these research activities are organized into three mechanical metamaterials (Fig. 1). interdisciplinary research groups (IRGs) each (Ka Yee Lee, Binhua Lin, Stuart Rice) and traditional materials. Physics faculty of David environments through internships. focused on theme at the forefront of modern the Institute of Molecular Engineering IRG 2 on Control of Active and Shape- Awschalom, Cheng Chin, Kathy Levin, David materials science: (Stuart Rowan, Juan De Pablo) to study Changing Materials aims to understand Schuster, and Jon Simon work collaboratively systems ranging from nanoscale colloids to and exploit the myriad ways that biology with faculty from Chemistry (Steve Sibener) IRG 1 on Dynamics at Soft Interfaces suspensions of micron-scale particles to truly has evolved to construct materials that and the Institute Molecular Engineering focuses on both scientific challenges and macroscopic granular materials. By examining spontaneously change shape or generate (Andrew Cleland, Aashish Clerk, Guilia Galli) technological opportunities that arise from how stress variations at an interface can alter force. A key feature of such biological to construct new Quantum Materials. Recently, Figure 2

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1

λ λ New Faculty: ee f f g g h h VINCENZO VITELLI = –1 = –1 1 1

−1 (a) −1 Since I was a child, I have been intrigued by a short poem from the non-linear and disordered. A many body (a) system far from equilibrium can evolve in time Italian polymath Leonardo Sinisgalli: Come il ragno costruisco col and usually displays a rich phenomenology niente, lo sputo, la polvere, un po’ di geometria (Like a spider I build difficult to predict using statistical mechanics λ out of nothing, spit, dust, a bit of geometry). In retrospect, these formalism. Non-linear behavior occurs λ verses crystallize my vision of theoretical physics as the never- whenever the response of a material is not simply proportional to the applied ending search for a representation of reality that is both minimalist perturbation, e.g. a sand pile that collapses (b) (c) and visionary. when just a couple of extra grains are added. An extra complication that we often face (b) (c) One of the joys of being a is to can be macroscopic grains, molecules or is that the structure of soft materials is Figure 1 witness the emergence of universal concepts the revolving mechanisms of a complicated amorphous or disordered. (a) A linkage that exhibit topologically edge state motion (c) Interacting and thermally fluctuating polymer lines that smoothly evolves into non-linear moving objects called (red) on a substrate acquire a collective tilt. The angle that and mathematical ideas capable of mechanical device. Usually, newcomers to solitons. measures the orientationof the red line is quantized and Analytical progress on these complex proportional to an integer valued topological invariant, C, explaining natural phenomena across very this field make a clear-cut decision between problems is sometimes possible by (b) Topological control of material failure via buckling in a called Chern number. flexible metamaterial. different energy, time and length scales. studying hard materials (where quantum concentrating on topological properties (For videos, see: home.uchicago.edu/~vitelli/videos.html) To avoid being overwhelmed by this sense of effects are dominant) or soft materials that are unaffected by smooth changes freedom, some constraints are needed to (ruled by classical physics). I have tried in material’s geometry and parameters. systems composed of directed polymers or orient abstract thinking. It is for this reason to sit on the fence between the two, unable Exploiting topological invariants is not vortex lines (see Figure 1c). that I have decided to focus my theoretical to see much of a distinction at the level only desirable from the perspective of Current efforts in my group are targeting research towards the study of materials, of mathematical models. In the end, much of mathematical modelling—it can be a useful a class of materials called active because a context where the constraints of reality my work concerns soft materials (membranes, principle in the design of robust materials and they are composed of many interacting and industrial applications are most stringent liquid crystals, glasses, grains, polymers, devices. The pursuit of topological materials microscopic components each endowed with and stimulating. complex fluids etc.), but it is often related to has traditionally concentrated on electronic an internal source of energy of biological or quantum matter. properties. My group has investigated My group is mostly interested in many synthetic origin. The central question that classical mechanical structures that mimic particle systems whose rich behavior emerges There are three recurrent features present guides our efforts in this area is the following. their topological quantum counterparts and from collective effects, rather than the (sometimes simultaneously) in the materials How can we extend the time honored physics often exhibit additional unexpected non- complexity of the basic components, which we study: they are often out of equilibrium, and engineering framework of Continuum linear response (see Figure 1(a–b)). A recent Mechanics to enable the theoretical highlight was to show how topologically description of active solids and fluids for protected surface patterning (similar to the “Exploiting topological invariants is not only desirable which energy is not conserved? Thouless pumping of Mott insulators) can from the perspective of mathematical modeling—it arise from the interplay of thermal fluctuations can be a useful principle in the design of robust and interactions in two dimensional classical materials and devices.”

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I grew up in Maryland just outside of DC. with at UChicago has been The Society of I grew up in Mesa, Arizona and actually which gave me direct access to undergraduate Student As a little kid I loved math; my parents used Women in Physics (or SWiP). I joined SWiP Student graduated from high school without ever students considering a physics major. This was to buy me math workbooks in addition as a first year and went with a group of older taking a physics course. I didn’t like the an important role for me because the positive to coloring books for long car trips! I took my students to the Conference for Undergraduate other science courses, so I never imagined I interactions I had with professors and TAs in Voices: first physics class during the fall semester of Women in Physics (CUWiP) in Michigan. Voices: would enjoy physics, especially since it had my undergraduate physics department greatly 9th grade (it was algebra based mechanics). Since then I have become the president of a reputation for being tedious and difficult. I influenced my decision to become a physicist. CLARE SINGER My high school teacher Mr. Schafer was the organization. It’s amazing to be able KATRINA MILLER did, however, discover that I had an affinity for Teaching also gave me a fresh appreciation fantastic and physics quickly became to contribute so much to the department mathematics—I enjoyed setting up equations for the subject I know and love, because I my favorite subject. I took two more physics and it inspires me to see so many younger and manipulating numbers to solve problems, learned how to think about the same physical classes in high school (modern physics students joining research labs and doing great and I even participated in competitions with concepts in the many new and creative ways and calculus based mechanics and e&m), internships. This year I was especially excited the school math club. But math is intimately my students came up with. but I think I had subconsciously decided I to be able to go back to CUWiP, this time in tied to physics, so in retrospect it was only a I won’t do much in the winter here because wanted to study physics in college after that Iowa, and take a group of 15 younger students matter of time before I developed a passion I hate the cold, but I come out of social first semester! with me! Young-Kee Kim has been doing for physics as well. hibernation in the summertime. You’ll incredible things for our department and I am I’ve always been a very driven person and I I first came to UChicago as an undergraduate always catch me at some happy hour, so grateful for her support of SWiP. like to challenge myself, so I knew I wanted REU student the summer before my senior music festival, or just out exploring different to go to college somewhere that would This summer I’m taking a little time off after year of college, and it was during this program neighborhoods in the city, as long as the challenge me. UChicago initially caught my graduation before starting a PhD at Caltech that I cemented my interest in astro/particle weather is sunny and warm! attention because of the reputation of in the fall. I will be in the Environmental physics because of the all the amazing Sometimes I think I’ll stay in academic our physics department and the pride Science and Engineering department working research I was exposed to. So I knew that research, other times I think about teaching we have in being quirky. Ultimately though with Tapio Schneider and John Seinfeld if I wanted to research in this area, UChicago at a liberal arts college, or even going the I chose UChicago because of the Core researching stratocumulus cloud dynamics. was the place to be. And yes, I did find national lab route. The most important curriculum: I wanted to have a college Longer term, I want to stay in research, maybe what I expected! UChicago has such a rich requirement for me is that I’m fulfilling experience that pushed me out of as a professor or working at a national lab, astro/particle research environment. I worked my passions—doing physics and teaching my intellectual comfort zone and let me but I’m also hoping to get more involved in on detection during my first physics—but there are so many different take classes like Introduction to the Hebrew science policy outreach. two years of graduate school and transitioned ways I can do that. I know for sure I won’t be Bible or Language and Violence. into the world of oscillations just Scav is still going strong. This year I was staying in Chicago—it’s too cold! As soon this summer. I’m not sure I knew what to expect when a captain of the Burton-Judson Scav team as I graduate I’m hoping to head back closer coming to UChicago, so I can’t say if it’s been and we got up to our usual mischief UChicago definitely turned me on to to home. what I expected, but it has been fantastic! and shenanigans: Michelin tire signed by a physics—the graduate student curriculum is Fun fact: when I finish my degree, I’ll be The research opportunities I’ve had with 3-star Michelin chef, many Kattenstoet demanding, but I have grown so much as a the third Black woman to earn her PhD from UChicago faculty and UChicago programs festivities, working mechanical replica of scientific thinker and researcher. My favorite the UChicago physics department. Willetta have been way beyond my imagination: Solomon’s Throne. research experience so far was spending a Greene-Johnson (1987) is now a professor at from building 20 foot tall towers of plastic few weeks in Italy last summer collecting data Loyola and Cacey Stevens Bester (2015) Z-shapes with Heinrich Jaeger to spending a for the XENON1T experiment at LNGS. This is now a post-doc at Duke. I’m excited to summer in Israel developing ink-jet printing was the first time I had ever been a part of continue their legacy and hope that it technologies for water filtration membranes in such a large collaboration of scientists, and paves the way for even more representation collaboration with the IME to participating in I felt so important running the detector! It in the future. an international field campaign for 4 weeks in put into perspective the magnitude of what I Nepal researching the Asian Monsoon could accomplish in graduate school. with Liz Moyer. Since coming here I have discovered that I Outside of classes and my research one of the love to teach! I was a teaching assistant last most meaningful things I’ve been involved year for the introductory physics courses,

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Prizes & Alumni

Awards AWARDS & ELECTIONS Reflection was awarded the APS Medal for Exceptional Achievement in Research for his “many fundamental contributions to space physics, plasma physics, solar physics and astrophysics for over 60 years.” Stuart Gazes has received a 2018 Quantrell Award SATOMI SHIRAISHI HEINRICH JAEGER was elected as a 2018 for Excellence in Undergraduate Teaching Fellow of the American Academy of Arts and Recently, I had the pleasure of speaking with physics students during Sciences; also awarded the Sewell L. Avery a career night at the Kersten Physics Training Center. Meeting students Distinguished Service Professorship nearing important crossroads reminded me of the myriad forms the post-graduation journey can assume. SHINSEI RYU was recently been named a Simons Investigator by the Simons I was born in Japan, and my grandparents were Nagasaki survivors. Foundation. This award is given to Just as their experiences had changed their lives, the stories they outstanding theoretical scientists. shared changed mine, as well. As I grew, I began to realize the good that radiation could bring to humanity and hoped one day to ABIGAIL VIEREGG was recently been named contribute to it. As the time came to put out college applications, the a 2018 Cottrell Scholar by Research University of Chicago caught my attention for its history of scientific Corporation for being an outstanding early discovery and innovation, including Enrico Fermi’s controlled nuclear career teacher-scholar. chain reaction. My research projects during my undergraduate and graduate studies included experimental particle physics, analyzing MARK OREGLIA was elected as a Fellow of the top quark lifetime at CDF, and pushing frontiers in -plasma the American Physical Society “for broad accelerator technologies with Dr. Wim Leemans at the Lawrence contributions to electron-position and proton- Berkeley National Laboratory. I finished my AB in physics in 2007 The Llewellyn John and Harriet Manchester Quantrell Awards, believed proton collider physics.” to be the nation’s oldest prize for undergraduate teaching, reflect the and Ph.D. in 2013 under the mentorship of Professor Young-Kee Kim. was elected as a Fellow College’s commitment to honor inspiring teachers. The Faculty Awards VINCENZO VITELLI Since then, I have pursued further studies in the medical physics for Excellence in Graduate Teaching and Mentoring recognize tenure- of the American Physical Society “for of radiation oncology, including post-doctoral research and clinical track and tenured faculty in the Biological Sciences, Divinity School, theoretical contributions to the field of residency training. This July, I started as a faculty member at Humanities, Institute for Molecular Engineering, Physical Sciences and topological mechanics.” Mayo Clinic in Rochester, Minnesota. I am excited to deepen my involvement in treating cancer patients in this role, as well as to Social Sciences. was elected as a Fellow of LIANTAO WANG research ways to advance radiation therapy with accelerator-based the American Physical Society “for novel photon and proton treatments. contributions to jet sub-structure studies..., facilitating LHC searches for Higgs boson, dark The coursework, learning philosophy, and research opportunities at matter, and new dynamics UChicago turned out to be excellent preparation for my career in in the electroweak sector.” medical physics. What to do with the knowledge you gain at UChicago depends on who you are and what excites you. My advice to those APPOINTMENTS & graduating: follow your heart and don’t give up! PROMOTIONS

DAVID AWSCHALOM has a new appointment in the Department of Physics. He is also a Professor in the Institute for Molecular Engineering.

DANIEL HOLZ and LIANTAO WANG were recently promoted to full Professor.

DAVID SCHUSTER and JON SIMON were recently promoted to Associate Professor. CP-2 / 21 CHICAGO PHYSICS 2 / TIED IN KNOTS

Recent Happenings INAUGURAL LECTURE

LECTURE SERIES New display in the Department of Physics recognizing UChicago “Dear Maria, Melissa Franklin, the Mallinckrodt Professor of Physics at Harvard oh my, National Medal of Science awardees. Marvin Cohen, PhD ’64, now how particle University, gave the first annual Maria Goeppert-Mayer Lecture on the University Professor of Physics at UC Berkeley pictured above physics has October 19, 2017. with current Physics Graduate Students. changed” Her lecture “Dear Maria, Oh My, How Particle These lectures are annually given by The 17 faculty and alumni of UChicago’s predicted the behavior of electrons; but they MELISSA Physics Has Changed” explored both a outstanding women , in honor of Department of Physics who won National also contributed to touchscreens, radar and FRANKLIN brief history of the particle accelerators that Maria Goeppert-Mayer. Goeppert-Mayer was THURSDAY Harvard University Medals of Science discovered the muon MRIs, advised presidents on nuclear security OCTOBER have made remarkable discoveries in a theoretical physicist who developed the neutrino, disproved symmetry and described and helped spread energy efficiency across particle physics possible and the slow turn nuclear shell model while at Argonne National the lives of stars. the U.S. Reception will follow the lecture. of experimentalists attention from the Laboratory and the University of Chicago 4:0019 PM Maria Goeppert-Mayer Lecture Hall discovery of the building blocks of matter to from 1946 to 1959. She received the 1963 KPTC 106 We will dedicate the Their ranks include the queen of carbon All 17 were honored Jan. 12 with a ceremony 5720 S. Ellis Ave. Maria Goeppert-Mayer Lecture Hall Chicago, IL 60637 during this reception. the study of the universe with nothing in it, in Physics for her “discoveries (Mildred Dresselhaus) and the father of energy at the University’s Kersten Physics Teaching the so-called vacuum. concerning nuclear shell structure.” efficiency (Arthur Rosenfeld). They fostered Center, where Provost Daniel Diermeier and new fields, solved some of the 20th century’s Prof. Young-Kee Kim, chair of the Department greatest scientific puzzles and literally set of Physics, unveiled a display along the the standards for modern science. They built building’s top floor highlighting each awardee. accelerators and detectors and “This is a wonderful opportunity to honor this department’s extraordinary history of “We wanted to give them a sense scientific achievement,” said Kim. “This floor has high student traffic, so we wanted to of history and pride, as well as give them a sense of history and pride, as On August 12th, NASA’s Parker Solar Probe blasted off into the well as encouragement—many of these great predawn darkness, on its way to explore the sun on a mission that encouragement—many of these great scientists were once students here on this will send it closer to our star than any previous spacecraft. scientists were once students here on campus, just like them.” With its liftoff, University of Chicago Professor UChicago. “[Now I] really have to turn this campus, just like them.” [Text: Louise Lerner, Photo: Jean Lachat, Event Poster: Graphic Arts] Emeritus Eugene Parker became the first from biting my nails…to thinking about all person to witness the launch of a namesake the interesting things which I don’t spacecraft. The Parker Space Probe is know yet. We’re in for some learning the the first NASA mission named in honor of a next several years.”

living person.

“All I can say is wow, here we go,” said Parker, [Source: https://news.uchicago.edu/story/nasa-solar-probe- who is the S. Chandrasekhar Distinguished named-after-uchicago-scientist-begins-historic-mission?] Service Professor Emeritus in Physics at

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Events Development

For full and future event listings, please visit: physics.uchicago.edu/google-events DEPARTMENT OF PHYSICS ESTABLISHES THE DEBORAH JIN FELLOWSHIP

PAST NOVEMBER 1, 2018 Deborah (Debbie) Jin was an internationally was 47. Jin earned an A.B. in physics from Argonne National Lab renowned physicist. In 2003, she received Princeton in 1990, and a Ph.D. in physics The American Physical Society has named a MacArthur Fellowship (commonly known from the University of Chicago in 1995 under Argonne National Laboratory an historic physics site in recognition of the pioneering work as a “genius grant”) from the John D. and supervision of Thomas Rosenbaum. From of former Argonne physicist and Nobel laureate Catherine T. MacArthur Foundation. In 1995 to 1997, she was a National Research . 2013, she was named the L’Oreal-UNESCO Council research associate at JILA, where

DECEMBER 7, 2018 For Women in Science Laureate for North she was hired in 1997 as a NIST physicist VanFEST America. Her other prestigious awards include and assistant professor at the University of A celebration of Van Bistrow’s 40+ years at the a 2002 Maria Goeppert Mayer Award, a 2004 Colorado, Boulder. University of Chicago and his contributions to Scientific American “Research Leader of physics instructional labs. About the Fellowship the Year,” a 2008 Benjamin Franklin Medal Debbie Jin was a role model and inspiration DECEMBER 8, 2018 in Physics, a 2014 Institute of Physics Isaac for scientists, men and women alike. Physics with a Bang! Newton Medal, and the 2014 Comstock Prize The Department is establishing the Fellowship Professors Heinrich Jaeger and Sid Nagel are in Physics. At the time of her election in 2005, the hosts for this fun holiday lecture for children, Physics with a Bang! 2018 to bring more outstanding women into Jin was the youngest member of the National families, students and teachers. science. Gifts of all sizes are appreciated. Academy of Sciences. DECEMBER 8, 2018 The Fellowship will be given to an incoming Forget the Year Debbie Jin passed away September 15, 2016, female physics graduate student at the The annual holiday event for the after a courageous battle with cancer. She University of Chicago. Department of Physics.

THE SOCIETY OF WOMEN IN PHYSICS

UPCOMING JANUARY 11, 2019 The Society of Women in Physics (SWiP) our current mentorship program that Physics Career Day group was established to provide supportive fosters connections between graduate and environment for undergraduate women and undergraduate women, as well as pilot MARCH 1, 2019 Forget the Year 2018 Graduate Student Open House access to resources for success in higher an outreach program at local schools to physics. While our society has largely grown expose and raise interest in physics with MARCH 6, 2019 in the last several years, we aim to increase younger girls as well. We are also very excited APS Alumni Event, Boston the number of resources for women to learn to bring back our quarterly speaker series, JUNE 14, 2019 about careers in physics as well as highlight with the goal of celebrating and learning The Department of Physics the ongoing achievements of successful about the work and experiences of local Graduation Reception female physicists. We intend on expanding female physicists every term.

Department of Physics Graduation, 2018 So many of the accomplishments associated with Physics at the University of Chicago have been made possible by the generous support of alumni, families, and friends through direct contributions and estate gifts. If you would like to support programs and places at the Department of Physics that are particularly meaningful to you, please visit our webpage: physics.uchicago.edu/support CP-2 / 25 CHICAGO PHYSICS 2 / TIED IN KNOTS

In Fond Memory...

JAMES W. CRONIN DEAN EASTMAN PETER FREUND HELLMUT FRITZSCHE LEON LEDERMAN 1931–2016 1940–2018 1936–2018 1927–2018 1922–2018

Professor Emeritus James W. Cronin, a Dean Eastman, director of Argonne from Professor Peter Freund was both a particle Professor Emeritus Hellmut Fritzsche spent Professor Emeritus Leon Lederman was a pioneering scientist who shared the Nobel 1996–1998 and professor emeritus at the physicist and writer who joined the physics his career exploring semiconductors— Nobel-winning physicist and scientific leader Prize in physics in 1980 for his groundbreaking University of Chicago, died on March 4, 2018, faculty at the university in 1965. His materials that are the foundation of modern with a passion for science education. With work on the laws governing matter at the age of 78. His tenure at the lab saw wide-ranging work in theoretical physics electronics. In particular, the experimental a career that spanned more than 60 years, and antimatter and their role in the universe. the Advanced Photon Source begin its had a strong mathematical flavor. “He was physicist became one of the world’s foremost Lederman, the Frank L. Sulzberger Prof. Cronin, SM’53, PhD’55, spent much of his operations and the Gammasphere (part of the frequently an early contributor in fields experts on amorphous semiconductors, Emeritus of Physics, became one of the most career at the University of Chicago, first as Argonne Tandem Linac Accelerator System) and theories that later rose to prominence,” working with inventor Stan Ovshinsky to turn important figures in the history of particle a student and then a professor. A University make its first move from Lawrence Berkeley said Jeff Harvey, the Enrico Fermi these materials into technology that would physics. He was responsible for several Professor Emeritus of Physics and Astronomy & Astrophysics, he was remembered this National Laboratory to Argonne. Distinguished Service Professor of Physics. define the late 20th century—TV displays, breakthrough discoveries, uncovering new week as a mentor, collaborator and visionary. “He had good taste.” computer memory and solar panels. particles that elevated our understanding of the fundamental universe, and he led These included supersymmetry and string A member of the UChicago faculty for nearly “He inspired us all to reach further into the construction of the Tevatron at Fermi [Source: https://researchinnovation.uchicago. theory, including a branch that tied string 40 years and a former chairman of the the unknown with deep intuition, solid edu/2018/04/10/in-memoriam-dean-eastman/] National Accelerator Laboratory, which theory with a mathematical concept called Department of Physics, Fritzsche died June 17 scientific backing and poetic vision,” said was the highest-energy accelerator in the p-adic numbers, as well as a concept called at age 91. Colleagues remembered Fritzsche’s , the Homer J. Livingston world for 30 years. Distinguished Service Professor in Astronomy AdS/CFT correspondence, which relates passion and energy, his intellectual generosity and Astrophysics. “He accepted his many quantum models of particles with quantum and his inventiveness in the laboratory. recognitions and accolades with so models of gravity. much humility that he encouraged many [Source: https://news.uchicago.edu/story/leon- lederman-nobel-winning-physicist-and-former-- generations to follow his vision.” (Louise Learner) director-1922-2018]

[https://news.uchicago.edu/story/peter-freund-particle- physicist-and-fiction-writer-1936-2018]

[Source: https://news.uchicago.edu/story/james-w-cronin- nobel-laureate-and-pioneering-physicist-1931-2016]

CP-2 / 27 Department of Physics Kersten Physics Teaching Center 5720 South Ellis Avenue Chicago, 60637-1434

So many of the accomplishments associated with Physics at the University of Chicago have been made possible by the generous support of alumni, families, and friends through direct contributions and estate gifts. If you would like to support programs and places at the Department of Physics that are particularly meaningful to you, please visit our webpage: physics.uchicago.edu/support