Jeffrey I. Mechanick, M.D. Quantum Biology Lecture

Jeffrey I. Mechanick (B.S. biology, 1981) established the Mechanick Quantum Biology Endowment fund to facilitate the dissemination of research findings on quantum mechanics and life sciences. Dr. Mechanick is a physician specializing in endocrinology, diabetes and bone disease, and is a Professor at the Icahn School of Medicine at Mount Sinai Hospital in New York. He is the past president of the American College of Endocrinology, the American Association of Clinical Endocrinologists and the American Board of Physician Nutrition Specialists.

Mechanick Lectures:

2019-20   Ron Walsworth, University of Maryland: Quantum Tools for the Life Sciences
2018-19   Martin Plenio, Ulm University: Vibrations, Quanta & Biology

Modified Superconductor Synapse Reveals Exotic Electron Behavior

JQI researchers modified a Josephson junction to include a sliver of topological crystalline insulator (TCI). Using this circuit, they detected signs of exotic quantum states lurking on the TCI's surface. (Credit: E. Edwards/JQI)

Electrons tend to avoid one another as they go about their business carrying current. But certain devices, cooled to near zero temperature, can coax these loner particles out of their shells. In extreme cases, electrons will interact in unusual ways, causing strange quantum entities to emerge.

At the Joint Quantum Institute (JQI), a group, led by Jimmy Williams, is working to develop new circuitry that could host such exotic states. “In our lab, we want to combine materials in just the right way so that suddenly, the electrons don’t really act like electrons at all,” says Williams, a JQI Fellow and an assistant professor in the University of Maryland Department of Physics. “Instead the surface electrons move together to reveal interesting quantum states that collectively can behave like new particles.”

These states have a feature that may make them useful in future quantum computers: They appear to be inherently protected from the destructive but unavoidable imperfections found in fabricated circuits. As described recently in Physical Review Letters, Williams and his team have reconfigured one workhorse superconductor circuit—a Josephson junction—to include a material suspected of hosting quantum states with boosted immunity.

Josephson junctions are electrical synapses comprised of two superconductors separated by a thin strip of a second material. The electron movement across the strip, which is usually made from an insulator, is sensitive to the underlying material characteristics as well as the surroundings. Scientists can use this sensitivity to detect faint signals, such as tiny magnetic fields. In this new study, the researchers replaced the insulator with a sliver of topological crystalline insulator (TCI) and detected signs of exotic quantum states lurking on the circuit’s surface.

Physics graduate student Rodney Snyder, lead author on the new study, says this area of research is full of unanswered questions, down to the actual process for integrating these materials into circuits. In the case of this new device, the research team found that beyond the normal level of sophisticated material science, they needed a bit of luck.

“I'd make like 16 to 25 circuits at a time. Then, we checked a bunch of those and they would all fail, meaning they wouldn’t even act like a basic Josephson junction,” says Snyder. “We eventually found that the way to make them work was to heat the sample during the fabrication process. And we only discovered this critical heating step because one batch was accidentally heated on a fluke, basically when the system was broken.”

Once they overcame the technical challenges, the team went hunting for the strange quantum states. They examined the current through the TCI region and saw dramatic differences when compared to an ordinary insulator. In conventional junctions, the electrons are like cars haphazardly trying to cross a single lane bridge. The TCI appeared to organize the transit by opening up directional traffic lanes between the two locations. 

The experiments also indicated that the lanes were helical, meaning that the electron’s quantum spin, which can be oriented either up or down, sets its travel direction. So in the TCI strip, up and down spins move in opposite directions. This is analogous to a bridge that restricts traffic according to vehicle colors—blue cars drive east and red cars head west. These kinds of lanes, when present, are indicative of exotic electron behaviors.

Just as the careful design of a bridge ensures safe passage, the TCI structure played a crucial role in electron transit. Here, the material’s symmetry, a property that is determined by the underlying atom arrangement, guaranteed that the two-way traffic lanes stayed open. “The symmetry acts like a bodyguard for the surface states, meaning that the crystal can have imperfections and still the quantum states survive, as long as the overall symmetry doesn’t change,” says Williams.

Physicists at JQI and elsewhere have previously proposed that built-in bodyguards could shield delicate quantum information. According to Williams, implementing such protections would be a significant step forward for quantum circuits, which are susceptible to failure due to environmental interference.

In recent years, physicists have uncovered many promising materials with protected travel lanes, and researchers have begun to implement some of the theoretical proposals. TCIs are an appealing option because, unlike more conventional topological insulators where the travel lanes are often given by nature, these materials allow for some lane customization. Currently, Williams is working with materials scientists at the Army Research Laboratory to tailor the travel lanes during the manufacturing process. This may enable researchers to position and manipulate the quantum states, a step that would be necessary for building a quantum computer based on topological materials.

In addition to quantum computing, Williams is driven by the exploration of basic physics questions. “We really don't know yet what kind of quantum matter you get from collections of these more exotic states,” Williams says. “And I think, quantum computation aside, there is a lot of interesting physics happening when you are dealing with these oddball states.”

Written by E. Edwards and S. Elbeshbishi

RESEARCH CONTACT
Jimmy Williams  This email address is being protected from spambots. You need JavaScript enabled to view it.

Peter Shawhan Awarded 2018 Kirwan Faculty Research and Scholarship Prize

University of Maryland Professor Peter Shawhan received the 2018 Kirwan Faculty Research and Scholarship Prize during the campus’ annual Faculty and Staff Convocation ceremony on September 12, 2018. The prize, which provides a $5,000 stipend, recognizes a faculty member for a highly significant work of research, scholarship or artistic creativity completed within the last three years.

“The Kirwan Prize for 2018 recognizes [Shawhan’s] leadership on a variety of aspects regarding the Laser Interferometer Gravitational-wave Observatory (LIGO) experiment, which provided the first detection of gravitational waves produced by colliding neutron stars, and [his] work in multimessenger astronomy,” said UMD President Wallace D. Loh.

Shawhan also received the USM Board of Regents faculty excellence award earlier this year.

He earned his bachelor’s degree in physics from Washington University in St. Louis, joined the UMD Department of Physics in 2006.

“I came to the University of Maryland because it has an excellent physics department with a lot of different research specialties,” Shawhan said. “I was also familiar with the university because I lived nearby when I was in high school. I participated in the Physics Olympics here and still have a pin from the event.”

Prior to joining UMD, Shawhan was a senior scientist at the California Institute of Technology working on gravitational waves. He first learned about the research field as a graduate student at the University of Chicago, where he earned a Ph.D. in physics in 1999.

“I was studying particle physics at Chicago,” Shawhan said. “But near the end of my Ph.D., my advisor, Bruce Winstein, called me up one evening. He said, ‘[LIGO Co-founder] Kip Thorne is going to be my house tomorrow. Why don’t you come over and talk about LIGO?’ And I got interested.”

Gravitational waves—which Albert Einstein predicted in 1916 as part of the theory of general relativity—are ripples in the fabric of spacetime. In 2015, the LIGO detectors located in Livingston, Louisiana, and Hanford, Washington, detected gravitational waves for the first time. The finding led to the 2017 Nobel Prize in physics for Thorne, Rainer Weiss and Barry Barish.

As data analysis committee chair and a principal investigator of the LIGO Scientific Collaboration (LSC), Shawhan helped the collaboration conclude that the first gravitational waves detected came from the merger of two black holes that produced a single, more massive spinning black hole. In particular, Shawhan helped validate the analysis software that identified the black-hole merger signal a few minutes after the LIGO detectors recorded it. Shawhan also acted as a liaison with collaborating astronomers, performing rapid data analysis and sharing the results with them.

The detection of gravitational waves made it possible to study cosmological events using both gravitational wave detectors and electromagnetic telescopes, which can collect information about events using the entire spectrum of light. Shawhan led the LSC in developing this combined approach, called multimessenger astronomy.

“I first got into multimessenger astronomy in 2007, when a colleague donated telescope time so that some students and I could observe galaxies that our gravitational wave data suggested could be interesting,” Shawhan said. “We realized pretty quickly that it was hard work and we should leave it to professional astronomers, so we switched to collaborating with them.”

To quickly share information with astronomers collaborating with the LSC on multimessenger astronomy studies, Shawhan and his students developed a pipeline to rapidly process and check data from possible gravitational wave events. In addition, Shawhan recruited interested astronomers and helped them strategize about how to best follow up on gravitational wave observations.

Shawhan is particularly proud of the intense multimessenger astronomy campaign that followed the first detection of a merger event between two neutron stars—the dense, collapsed cores that remain after large stars die in a supernova explosion.

On August 17, 2017, gravitational waves from the merger arrived at the twin LIGO detectors. About two seconds later, NASA’s Fermi Gamma-ray Space Telescope detected a gamma-ray burst from the same source. Then, astronomers around the globe directed more than 70 space- and ground-based telescopes toward the event for follow-up observations.

Shawhan called the event one of the best moments of his research career.

“The neutron star merger event was the really spectacular breakthrough that we’d been hoping for,” Shawhan said. “It was just such a rich discovery. The fact that we had so many astronomers lined up to be ready to follow it up really paid off. “

UMD’s long history in the field of gravitational waves provided a boost to his research, Shawhan said. He specifically cited the influence of Physics Professor Emeritus Ho Jung Paik, who developed more sensitive detectors for gravitational waves and helped create the job opportunity that led Shawhan to UMD in the first place.

Today, UMD continues to provide Shawhan with opportunities to further his research.

“The physics department has been very supportive of my work on gravitational waves over the years,” Shawhan said. “It is also great to be able to collaborate with the Department of Astronomy, the Joint Space-Science Institute and NASA’s Goddard Space Flight Center. Through my involvement with them, I’ve become more involved in astrophysics. I’m actually getting involved in some space missions now!”

shawhan regalia pic 2018Provost Rankin, Peter Shawhan and President Loh

Media Relations Contact: Irene Ying, 301-405-5204, This email address is being protected from spambots. You need JavaScript enabled to view it.

Ted Jacobson Named Distinguished University Professor

Ted Jacobson has been named a University of Maryland Distinguished University Professor. This designation is the campus’ highest academic honor, reserved for those whose scholarly achievements “have brought distinction to the University of Maryland.” He was cited for his highly innovative work in black hole thermodynamics, the nature of spacetime, and gravitational physics.

Jacobson received his Ph.D. at the University of Texas and held postdoctoral appointments at the Observatoire de Meudon and Institute Henri Poincaré, Paris; the University of California at Santa Barbara, and Brandeis University before joining UMD as an assistant professor in 1988. He has since held appointments at the University of Bern, the Kavli Institute for Theoretical Physics in Santa Barbara, the Université de Paris VII and the Institute d’Astrophysique in Paris, the University of Utrecht and the Schrödinger Institute of Vienna. Jacobson is a Distinguished Visiting Research Chair at the Perimeter Institute for Theoretical Physics, where he spent part of a 2013-14 sabbatical. He has been a Simons Distinguished Visiting Scholar at the Kavli Institute for Theoretical Physics in Santa Barbara, and in 2015 was co-coordinator of its six-month research program Quantum Gravity Foundations: UV to IR.

Jacobson is a member of the Maryland Center for Fundamental Physics and the Joint Space-Science Institute and a Fellow of the American Association for the Advancement of Science and of the American Physical Society. He was an invited speaker at Stephen Hawking’s 75th birthday conference in 2017, where he spoke on "Hawking radiation, infinite redshifts, and black hole analogues”.

He is a UMD Distinguished Scholar-Teacher, and he co-developed the College Park Scholars Program Science, Discovery and the Universe

His work has been featured in the lay press, including The Economist and Salon.com. He has written for Scientific American, including a cover story, “Echoes of Black Holes.  In 2010, the New York Times published a feature story on gravity and highlighted Jacobson’s 1995 paper “Thermodynamics of Spacetime: The Einstein Equation of State”.  This paper showed that Einstein's equation for the curvature of spacetime derives from thermodynamic principles applied to entanglement entropy of the quantum vacuum. The idea was inspired by black hole thermodynamics, one of his main research foci. His other research interests have included laboratory analogs of black holes, astroparticle and gravitational tests of relativity, and relativistic plasma physics.