News: Faculty

$2 Million award recognizes curiosity-driven basic research in chemistry and physics.

The Brown Science Foundation announced March 8 that it has chosen University of Chicago Prof. William Irvine for its inaugural Brown Investigator Award. The award, which recognizes curiosity-driven basic research in chemistry and physics, supports the investigators’ research with $2 million over five years to their respective universities. Irvine, who researches fundamental problems in fluid dynamics and condensed matter, is one of two scientists chosen, along with David Hsieh of Caltech.

“Even among a strong group of candidates, Hsieh and Irvine stood out for their scientific vision and willingness to take risk,” said Marc Kastner, senior science advisor for the Science Philanthropy Alliance and chairman of the foundation’s scientific advisory board, which selected the winners. “They’re clear examples of America’s reservoir of mid-career scientists with the proven track record and restless minds needed to advance daring ideas.”

The Brown Science Foundation, a member of the Science Philanthropy Alliance, was established in 1992 by Ross M. Brown. The foundation announced its invitation-only Brown Investigator Award program in 2020 with plans to make eight awards annually by 2025. The program supports the often-overlooked resource of mid-career physics and chemistry researchers in the U.S. According to its website, the foundation is “dedicated to the belief that scientific discovery is a driving force in the improvement of the human condition.”

Press Release

Discovery addresses problem of generating and moving energy efficiently.

Three scientists from the Maziotti group in the JFI have run the numbers, and they believe there may be a way to make a material that could conduct both electricity and energy with 100% efficiency—never losing any to heat or friction.

The breakthrough, published Feb. 18 in Physical Review B, suggests a framework for an entirely new type of matter, which could have very useful technological applications in the real world. Though the prediction is based on theory, efforts are underway to test it experimentally.

“We started out trying to answer a really basic question, to see if it was even possible—we thought these two properties might be incompatible in one material,” said co-author and research adviser David Mazziotti, a professor of chemistry and the James Franck Institute and an expert in molecular electronic structure. “But to our surprise, we found the two states actually become entangled at a quantum level, and so reinforce each other.”

Graduate student LeeAnn Sager began to wonder how the two states could be generated in the same material. Mazziotti’s group specializes in exploring the properties and structures of materials and chemicals using computation, so she began plugging different combinations into a computer model. “We scanned through many possibilities, and then to our surprise, found a region where both states could exist together,” she said.

“Being able to combine superconductivity and exciton condensates would be amazing for lots of applications—electronics, spintronics, quantum computing,” said Shiva Safaei, a postdoctoral researcher and the third author on the paper. “Though this is a first step, it looks extremely promising.”

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Physics World

Breakthrough creates tough material able to stretch, heal and defend itself.

While eating takeout one day, James Franck Institute scientists Bozhi Tian and Yin Fang started thinking about the noodles—specifically, their elasticity. A specialty of Xi’an, Tian’s hometown in China, is wheat noodles stretched by hand until they become chewy—strong and elastic. Why, the two materials scientists wondered, didn’t they get thin and weak instead?

They started experimenting, ordering pounds and pounds of noodles from the restaurant. “They got very suspicious,” Fang said. “I think they thought we wanted to steal their secrets to open a rival restaurant.”

But what they were preparing was a recipe for synthetic tissue—that could much more closely mimic biological skin and tissue than existing technology.

“It turns out that granules of common starch can be the missing ingredient for a composite that mimics many of the properties of tissue,” said Fang, a UChicago postdoctoral researcher and lead author of a new paper published Jan. 29 in the journal Matter. “We think this could fundamentally change the way we can make tissue-like materials.”

The breakthrough allows the synthetic tissue to stretch in multiple directions but to heal and defend itself by reorganizing its internal structures —which is how human skin protects itself. The discovery could one day lead to applications from soft robotics and medical implants to sustainable food packaging and biofiltration.

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For contributions toward understanding novel phases in strongly interacting many-body systems and introducing original cross-disciplinary techniques.

Physicist Dam Thanh Son, University Professor at the University of Chicago, has been awarded the 2018 ICTP Dirac Medal for his contributions to revolutionizing human understanding of how quantum mechanics affects large groups of particles.

Son was awarded the medal with physicists Subir Sachdev of Harvard University and Xiao-Gang Wen of the Massachusetts Institute of Technology. The three winners made independent contributions toward understanding novel phases in strongly interacting many-body systems, according to the Abdus Salam International Centre for Theoretical Physics, which awards the Dirac Medal.

“I feel very honored to receive this award alongside two colleagues I deeply respect,” Son said. “The prize is especially valuable to me because ICTP is an institution created to help scientists from the developing world, and I am from Vietnam.”

Son joined the UChicago faculty in 2012 and serves as University Professor in Physics, the Enrico Fermi Institute, James Franck Institute and the College. University Professors are selected for internationally recognized eminence in their fields as well as for their potential for high impact across the University.

Press Release

Current-constrained approach significantly improves upon prior methods.

The smaller and smarter that phones and devices become, the greater the need to build smaller circuits. Forward-thinking scientists in the 1970s suggested that circuits could be built using molecules instead of wires, and over the past decades that technology has become reality.

“Current models tend to overpredict conductance, but our theory outperforms traditional models by as much as one to two orders of magnitude,” said Prof. David Mazziotti, Professor of Chemistry and the James Franck Institute, who coauthored the paper, published May 31 in Nature’s Communications Chemistry.

“Almost all of the big problems that people are trying to solve involve working with materials that are difficult to explore with traditional methods,” he said. “If we can better predict the conductivity, we can more effectively design better molecules and materials.”

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Recognition for Laurie Butler, Heinrich Jaeger, and Andrei Tokmakoff.

Laurie Butler is a Professor of chemistry with the James Frank Institute. She investigates fundamental inter- and intramolecular forces that drive the courses of chemical reactions, integrating our understanding of quantum mechanics into chemistry. Among other applications, her current work has implications for our models of atmospheric and combustion chemistry. She is a fellow of the American Physical Society and a former Alfred P. Sloan Fellow.

Heinrich Jaeger is the Sewell L. Avery Distinguished Service Professor in the Department of Physics and the James Franck Institute. His laboratory studies the investigation of materials under conditions far from equilibrium, especially to design new classes of smart materials. A focus of Jaeger’s work are granular materials, which are large aggregates of particles in far-from-equilibrium configurations, that exhibit properties intermediate between those of ordinary solids and liquids – which could lead to everything from soft robotic systems that can change shape to new forms of architectural structures that are fully recyclable. He is a former Fulbright Scholar and Alfred P. Sloan Research Fellow and is currently a fellow of the American Physical Society.

Andrei Tokmakoff is the Henry J. Gale Distinguished Service Professor of Chemistry with the James Franck Institute. He studies the chemistry of water, and molecular dynamics of biophysical processes such as protein folding and DNA hybridization. His lab uses advanced spectroscopy to visualize how molecular structure changes with time to study these problems. He was an Alfred P. Sloan Fellow and has received the American Physical Society’s Ernest Plyler Prize, among others.

Contact line deposits in an evaporating drop.

The year 2018 marks the 25th anniversary of Physical Review E. To celebrate the journal’s rich legacy, during the upcoming year we highlight a series of papers that made important contributions to their field. These milestone articles were nominated by members of the Editorial Board of Physical Review E, in collaboration with the journal’s editors. The 25 milestone articles, including an article for each calendar year from 1993 through 2017 and spanning all major subject areas of the journal, will be unveiled in chronological order and will be featured on the journal website.

For the year 2000, the following collaborative work from three groups in the James Franck Institute is featured:

Contact line deposits in an evaporating drop
Robert D. Deegan, Olgica Bakajin, Todd F. Dupont, Greg Huber, Sidney R. Nagel, and Thomas A. Witten
Phys. Rev. E 62, 756 (2000)

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Study examines how to manipulate photons for quantum engineering.

Quantum systems behave according to the strange laws that govern the smallest particles in the universe, like electrons. Scientists are increasingly interested in exploring new ways to harness the particles’ odd behaviors, like being in two states at once, and then choosing one only when measured.

Jonathan Simon, the Neubauer Family Assistant Professor of Physics and the James Franck Institute, is interested in how walls dividing matter and light begin to break down at this scale. Most electronic systems use electrons as the moving parts, but photons can display quantum properties just as easily as electrons—and photons’ quirks could both offer advantages as technologies and serve as models to understand the more slippery electrons. So his team wants to manipulate and stack photons to build matter out of light.

“Essentially we want to make photon systems into a kind of quantum Legos—blown-up materials that you can more easily study and tease out basic quantum design principles,” said Simon, who is also a fellow of the Institute for Molecular Engineering.

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Amorphous topological insulators constructed from random point sets.

Using a set of gyroscopes linked together, physicists explored the behavior of a material whose structure is arranged randomly, instead of an orderly lattice. They found they could set off one-way ripples around the edges, much like spectators in a sports arena—a “topological wave,” characteristic of a particularly unusual state of matter.

Published Jan. 15 in Nature Physics, the discovery offers new insight into the physics of collective motion and could one day have implications for electronics, optics or other technologies.

The team, led by Assoc. Prof. William Irvine, used gyroscopes—the top-like toys you played with as a kid—as a model system to explore physics. Because gyroscopes move in three dimensions, if you connect them with springs and spin them with motors, you can observe all kinds of things about the rules that govern how objects move together.

“Everything up to this point was engineered. We thought you had to build a particular lattice, and that determines where the wave goes,” said Irvine. “But when we asked what happened if you took away the spatial order, no crystal plane, no clear structure…the answer’s yes. It just works.”

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Observe particles acting coherently as they undergo phase transitions.

A study published Dec. 18 in Nature Physics by University of Chicago scientists observed how particles behave as the change takes place in minute detail. In addition to shedding light on the fundamental rules that govern the universe, understanding such transitions could help design more useful technologies.

One of the questions was whether, as particles prepare to transition between quantum states, they can act as one coherent group that “knows” the states of the others, or whether different particles only act independently of one another, or incoherently.

Cheng Chin, Professor in the James Franck Institute and Department of Physics, and his team looked at an experimental setup of tens of thousands of atoms cooled down to near absolute zero. As the system crossed a quantum phase transition, they measured its behavior with an extremely sensitive imaging system.

The conventional wisdom was that the atoms should evolve incoherently after the transition--a hallmark of older “classic” rather than quantum models of physics. “In contrast, we found strong evidence for coherent dynamics,” said graduate student Lei Feng, the first author on the study. “In no moment do they become classical particles; they always behave as waves that evolve in synchrony with each other, which should give theorists a new ingredient to include in how they model such systems that are out of equilibrium.”

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Demonstrates the power of modern computing for simulating viruses.

Computer modeling has helped a team of scientists, including several scholars from the the Voth group in the JFI, to decode previously unknown details about the process by which HIV forces cells to spread the virus to other cells. The findings, published Nov. 7 in Proceedings of the National Academy of Sciences, may offer a new avenue for drugs to combat the virus.

A key part of HIV’s success is a nasty little trick to propagate itself inside the body. Once HIV has infected a cell, it forces the cell to make a little capsule out of its own membrane, filled with the virus. The capsule pinches off—a process called “budding”—and floats away to infect more cells. Once inside another unsuspecting cell, the capsule coating falls apart, and the HIV RNA gets to work.

Scientists knew that budding involves an HIV protein complex called Gag protein, but the details of the molecular process were murky. “For a while now we have had an idea of what the final assembled structure looks like, but all the details in between remained largely unknown,” said Gregory Voth, the Haig P. Papazian Distinguished Service Professor of Chemistry and corresponding author on the paper.

Since it’s been difficult to get a good molecular-level snapshot of the protein complex with imaging techniques, Voth and his team built a computer model to simulate Gag in action. Simulations allowed them to tweak the model until they arrived at the most likely configurations for the molecular process, which was then validated by experiments in the laboratory of Jennifer Lippincott-Schwartz at the National Institutes of Health and the Howard Hughes Medical Institute Janelia Research Campus.

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Reveals new form of spontaneous quantum scattering in a driven many-body system.

“This is a very fundamental behavior that we have never seen before; it was a great surprise to us,” said study author Cheng Chin, Professor of Physics and in the JFI. Published Nov. 6 in Nature, the research details a curious phenomenon — seen in what was thought to be a well-understood system — that may someday be useful in quantum technology applications.

Chin’s lab studies what happens to particles called bosons in a special state called a Bose-Einstein condensate. When cooled down to temperatures near absolute zero, bosons will all condense into the same quantum state. Researchers applied a magnetic field, jostling the atoms, and they began to collide—sending some flying out of the condensate. But rather than a uniform field of random ejections, they saw bright jets of atoms shooting together from the rim of the disk, like miniature fireworks.

The tiny jets may show up in other systems, researchers said and understanding them may help shed light on the underlying physics of other quantum systems.

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Recognized by ETH Zürich at Materials Day 2017 meeting.

The ETH Materials Research Prize for Young Investigators recognizes outstanding contributions of young investigators that advance materials, from fundamental to applied research. These contributions could include, for example: the discovery of new classes of materials, the observation of novel phenomena leading to either fundamentally new applications and insights, and work that substantially impacts our understanding or applications of existing materials and phenomena.

Bozhi Tian, Assistant Professor at the University of Chicago, triumphed over stiff competition. Tian researches interactions between biological and electronic systems; for example, he examines how the behaviour of cells can be mimicked with semiconducting nanomaterials or how special nanomaterials can be used to measure the electrical conductivity of cells.

“Tian combines hard and soft materials in his research and connects the living with the lifeless,” explains Ralph Spolenak, Professor of Nanometallurgy and Head of the Department of Materials at ETH Zürich. “The bridge between these two poles is a major area in today’s materials science, one that is not only important for medicine, but also enables interesting applications in many other areas.”

Utilizing gas-surface collisions on patterned silicon.

In a paper published in Physical Review Letters, a team led by Prof. Steven J. Sibener describes a way to separate isotopes of neon using a beam of gas aimed at a precisely patterned silicon wafer, which reflects the different isotopes at slightly different angles. The method could one day be a less costly and more energy-efficient way to separate isotopes for medicine, electronics and other applications.

“One can think about it like separating the various colors of light into a rainbow using a prism,” said Sibener, the Carl William Eisendrath Distinguished Service Professor of Chemistry and the James Franck Institute. “This is a wonderful and very precise demonstration study, and we are very pleased with the results,” Sibener said. “It has been a delight to run down to the lab every day to see what’s happened. We’re very much looking forward to planning the next steps in this project to explore other atoms and molecules.”

Viewpoint
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For experiments and theory on the topological aspects of fluid dynamics and mechanical metamaterials.

William Irvine was recently elected a Fellow of the American Physical Society, nominated by the Topical Group on Soft Matter. The criterion for APS Fellow election is exceptional contributions to the physics enterprise; e.g., outstanding physics research, important applications of physics, leadership in or service to physics, or significant contributions to physics education. Fellowship is a distinct honor signifying recognition by one's professional peers.

Research for the Irvine group was recently featured on the cover of Physics Today. The Irvine Group at the University of Chicago has put a new twist on the smoke ring. Instead of blowing smoke into the air to create and visualize swirling flows known as vortex rings, they drove 3D-printed hydrofoils, lined with fluorescent dye, through water. Here, the wispy outer ring of white dye reveals a vortex ring; the orange and green trails are a tomographic reconstruction of the ring’s evolution over time. To learn how the group’s technique helped unveil hidden structure in fluid vortices, see the story.

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