News Archives - Physics & Astronomy

Joint Physics Faculty Elected APS Fellows

October 31, 2025

An-Ping Li, Credit: Genevieve Martin at ORNL Media

Two UT Physics Joint Faculty Professors have been elected Fellows of the American Physical Society (APS), an honor that recognizes excellence in physics and exceptional service to the physics community.

An-Ping Li leads the Scanning Tunneling Microscopy Group and the Heterogeneities in Quantum Materials Theme at the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory (ORNL). He was recognized for pioneering contributions to multiprobe and spin-sensitive scanning tunneling microscopy that enable groundbreaking advances in understanding and control of atomic defects, interfaces, and precision synthesis.

Bronson Messer is Director of Science for the Oak Ridge Leadership Computing Facility (OLCF) at ORNL. The Forum on Outreach and Engaging the Public elected him a Fellow for conveying the excitement and universal impact of physics to students, teachers, professionals, and the public via talks, multimedia, laboratory tours, popular national events, and for direct outreach to underserved Appalachian students and teachers.

Joint faculty appointments broaden opportunities for research collaborations and mentorship, allowing students to pursue master’s- and doctoral-level research at national laboratories. When Li joined ORNL as a research associate he began working with Physics Professor Hanno Weitering. After establishing himself as an independent researcher at the national laboratory, he developed a research program with the university as a joint faculty member and has mentored seven postdoctoral fellows from UT, including Wonhee Ko (who’s now an assistant professor). Messer has been the primary advisor for three UT Physics graduate students and has co-supervised eight others. He’s also a departmental alumnus, earning a bachelor’s degree in 1991 and a PhD in 2000. He translates that experience into the outreach that made him an APS Fellow.

“I think I was lucky to have ‘landed’ in the department as an undergraduate,” Messer said. “I had no idea what college or science or research was about. At all. I got excellent training, and I’m very interested in making sure that students who sound like me and might be just as bewildered get a feel for science being a process and a discipline, rather than being some secret writ.”

Affiliated faculty’s contributions to advancing physics research, training next-generation scientists, and inspiring public interest amplify the department’s impact in meeting the university’s land-grant mission and aspirations. This new class of APS Fellows joins 10 full-time physics faculty who have earned the honor, along with four Fellows of the American Association for the Advancement of Science.

NSF CAREER Award for Joon Sue Lee

October 14, 2025

Assistant Professor Joon Sue Lee has won a prestigious CAREER award from the National Science Foundation (NSF) to advance the creation of quantum materials for new quantum devices. He is the ninth member of the current physics faculty to win this award and one of three recent UT recipients.

Atomic-Scale Engineering

The NSF CAREER program supports early-career faculty with the potential to be academic role models in research and education. Since joining the department in 2020, Lee has won back-to-back teaching awards and built a research group that specializes in developing quantum materials, especially those with potential applications in quantum technologies.

The transistors and semiconductors that power smartphones and biosensors were built on understanding electrical properties. Future quantum technologies rely on the fascinating but atypical workings of quantum mechanics. In systems so small they’re measured in atoms, the physics tends to go off script. Particles can be in multiple states at the same time or they may be entangled. Properties don’t exist until they’re measured. Lee’s work navigates through this landscape to make new materials and devices for a modern world. With this NSF support, he’ll focus on a single-element material—tin (Sn)—because it has a dramatically different personality.

“Tin has two different structures,” he said. “Alpha phase is topological. Beta phase is superconducting. If you can control the growth of each phase, then you can control the electrical properties.”

Superconductivity allows electrical current to flow with no resistance. Topological phases, on the other hand, are defined by the global arrangement of a material’s electronic wavefunctions—its band topology. In conventional materials, the conduction and valence bands remain distinct. However, in topological materials, these bands can invert due to strong spin-orbit coupling.

“This inversion changes the material’s topological order, creating protected surface or edge states that allow electrons to travel without scattering,” Lee explained.

Such states are remarkably robust against defects and impurities, giving rise to exotic behaviors that bridge fundamental quantum physics and potential device applications. Combining superconductivity and topology gives scientists exciting opportunities for new technologies.

“Topological superconductivity, for example, is one of the most promising routes toward quantum computing,” Lee said. “That’s one of the big motivations.”

Using the Molecular Beam Epitaxy resources at UT’s Institute for Advanced Materials, Lee grows thin films, one layer of atoms at a time, on crystalline substrates. His goal is to selectively grow pure superconducting and topological phases of tin and put them together into structures with “atomically precise” interfaces.

“If we can achieve that, then we will be able to design materials where one area has one structure and the adjacent area has the second structure,” he said.

By adjusting the lattice parameters of underlying buffer layers of those areas, he can tune the tin phases and control their electrical properties.

“We want to explore the basic physics in these electrical states,” he said, “and also develop devices that could lead to future quantum applications.”

Professor and Department Head Adrian Del Maestro said that “Lee’s work harnesses the quantum behavior of materials for new technologies, including novel superconductors that can be used for sensing and energy applications. His lab is always bustling with undergraduate and graduate students, where he is training the workforce of tomorrow.”

The work aligns well with the university’s strategic focus on advanced materials and manufacturing innovation gateway, part of a concentrated effort to make the most of UT’s expertise to tackle grand challenges. Lee, who has won teaching awards from the College of Arts and Sciences and the UT Alumni Association, also plans to share this research with undergraduates to inspire a new generation of scientists.

“I plan to use the data from our samples to explain or demonstrate superconductivity or topological properties in class,” he said. He added that he can also use semiconductors and insulators in his lab and “those can help students understand electrical properties of different materials.”

Lee’s five-year project began in August and includes $749,441 to support his work. He is the ninth member* of the current physics faculty to win an NSF CAREER award. The program has supported the department’s wide range of expertise, including research in condensed matter, elementary particles, biophysics, and nuclear theory.

*Adrian Del Maestro, Steven Johnston, Larry Lee, Jian Liu, Norman Mannella, Jaan Mannik, Lucas Platter, and Haidong Zhou have all won NSF CAREER Awards.

TRAINING THE NEXT GENERATION

Graduate Student Pradip Adhikari joined Joon Sue Lee’s research group in the fall of 2020 and is one of 11 graduate students to win a Graduate Advancement, Training, and Education (GATE) Award for the 2025-2026 academic year. These awards from the UT-Oak Ridge Innovation Institute’s Science Alliance support collaborative research between the university and Oak Ridge National Laboratory, providing outstanding graduate students with a 12-month appointment including a stipend, tuition, and benefits.

While he isn’t working directly on the NSF CAREER research, Lee explained that “in Pradip’s case, he’s using a different material system (but) it’s the same motivation; the same big idea about topological materials and superconductivity.”

Adhikari’s project is the device-scale interplay of unconventional superconductivity and magnetism. While they typically have an adversarial relationship (usually leading to the suppression of one state by the other) he is working with a combination of iron, tellurium, and selenium, or FeTeSe, which is a notable example of an unconventional superconductor with co-existing superconductivity and magnetism.

“The interplay of topology, magnetism, and superconductivity gives rise to exotic and robust quantum states, making such materials a fertile ground for discovering new physics,” Adhikari said. “My research interest lies in the synthesis of high-quality topological materials, fabricating devices from them, and studying their properties at the device scale. I am particularly excited by how the unique electronic behaviors of these materials can be explored and harnessed for next-generation quantum technologies.”

One Experiment: Three Discoveries

October 13, 2025

You can’t have gold until a nucleus decays. The specifics of that process have been hard to pin down, but UT’s nuclear physicists have published three discoveries in one paper explaining key details. The results can help scientists come up with new models to describe the stellar processes that give us heavy elements, as well as make better predictions about the expanding landscape of exotic nuclei.

The Physics of Bling

Elements like gold and platinum are created under extreme conditions, like when stars collapse, explode, or collide. In the rapid neutron-capture process (or r-process for short), a nucleus captures a barrage of neutrons in quick succession until it becomes so heavy it decays into lighter, more stable nuclei. As it crosses the nuclide chart, the r-process path winds through territory where the main decay mode is beta decay of the parent nucleus, followed by the emission of two neutrons. The nuclei involved are difficult (if not impossible) to study experimentally, so the calculations describing them lean heavily on models that need to be validated in the lab.

To get a better picture of how all this happens, researchers including UT Graduate Students Peter Dyszel and Jacob Gouge, Professor Robert Grzywacz, Associate Professor Miguel Madurga, and Research Associate Monika Piersa-Silkowska and worked with a host of scientists from other institutions. Building on data analysis methods outlined by Research Assistant Professor Zhengyu Xu, they started with large amounts of indium-134.

“These nuclei are hard to make and require a lot of new technology to synthesize in sufficient quantities,” Grzywacz explained.

The ISOLDE Decay Station at CERN met the challenge by providing plenty of indium-134 nuclei, as well as sophisticated laser separation technology to make sure they were pristine. When indium-134 decays, it populates excited states in tin-134, tin-133, and tin-132. Using a neutron detector funded by the National Science Foundation Major Research Instrumentation program and built at UT, scientists made three important discoveries. At the top of the list, they made the first measurement of neutron energies for beta-delayed two-neutron emission.

The two-neutron emission is the biggest deal,” Grzywacz said.

Beta-delayed two-neutron emission occurs only in exotic nuclei, those that are short lived and unstable. The two-neutron separation energy is very small, but in this experiment it was enough to be measured.

“The reason this is hard is because neutrons like to bounce around. It’s hard to tell if it’s one or two,” Grzywacz explained. In earlier attempts, “no one measured energies,” so this approach “opens a completely new field.”

This is the first study detailing the two-neutron emission for a nucleus that follows the r-process path, opening the door for clearer models about how stellar events can create elements like gold.

Tin Never Forgets

A second discovery was the first observation of a long-sought single-particle neutron state in tin-133. Grzywacz explained that “tin is in an excited state. (It) has to cool off. It can spit out a neutron, or, with enough energy, it can spit out two neutrons. It should always spit two neutrons, but it doesn’t.”

He said the traditional view is that tin “boils off” neutrons to cool down, becoming “an amnesiac nucleus,” with no memory of beta decay.

“We say the tin doesn’t forget,” Grzywacz said. “This ‘shadow’ of indium doesn’t completely disappear. The memory is not erased.”

In this experiment, state-of-the-art neutron detectors identified this elusive state, indicating that a better theoretical framework is needed to understand why sometimes one neutron is emitted and sometimes two are.

“People were searching for it for 20 years and we found it,” Grzywacz said. “Those two neutrons allowed us to see this state.”

He explained that this newly-observed state is an intermediate step in the two-neutron emission process. It’s also the last elementary excitation in the tin-133 nucleus, completing the picture and helping make calculations more accurate.

Better calculations and modeling are tied to the third discovery this research brought to light—the observation of non-statistical population of this newly-observed state. Grzywacz explained that the decay process is relatively clean, so everything is separate with no neighboring states.

“You’re not making split-pea soup,” he said. “Still, in most cases it behaves like split-pea soup. Somehow this statistical mechanism happens. Why is it statistical, even though it shouldn’t be and why in our cast it isn’t”?

The results indicate that as you travel the across the nuclear landscape, farther from stability and into realm of exotic nuclei like Tennessine, the old models don’t hold and new ones are needed.

A photo of Peter Dyszel in a physics lab — Peter Dyszel

The Pursuit of Curiosity

The need for new models to explain nuclear origins and structure presents a tremendous opportunity for graduate students like Dyszel. He joined Grzywacz’s group in 2022 and was the first author on the Physical Review Letters paper outlining the three discoveries. His to-do list on this experiment was a long one, from constructing physical pieces to interpreting the results. He built frames for the neutron tracking detectors and assembled them in the experimental setup. He set up the required electronics and made beta detectors. He ran test measurements, helped with software for data acquisition, made corrections for optimal timing resolution, and analyzed the experimental data. With all that, Dyszel’s work was still part of a multi-person effort.

“The success of this work is due in part to my colleagues and collaborators, whose guidance and constructive input were crucial,” he said.

A native of Jacksonville, Florida, Dyszel came to UT after finishing a bachelor’s in physics at the University of North Florida. His road to PRL authorship actually began in a general chemistry course when he first learned about beta decay. Intrigued by the thought that nuclear transformations could generate elements with a whole set of different properties, he thought he’d go for a bachelor’s in chemistry.

“It was not until I started my bachelor’s degree that I had stepped foot into a physics class, which instantaneously drove me towards a degree in physics,” he explained. “I’ve always been interested in understanding how the world works, and physics has been, and continues to be, the path I want to follow in pursuit of that curiosity.”

A Night at the Planetarium: From Earth to the Universe

October 3, 2025

An image of Earth against a backdrop of stars with the text From Earth to the Universe

The night sky, both beautiful and mysterious, has been the subject of campfire stories, ancient myths and awe for as long as there have been people. A desire to comprehend the Universe may well be humanity’s oldest shared intellectual experience. Yet only recently have we truly begun to grasp our place in the vast cosmos. To learn about this journey of celestial discovery, from the theories of the ancient Greek astronomers to today’s grandest telescopes, we invite you to experience From Earth to the Universe on Friday, October 10.

This stunning, 30-minute voyage through space and time—the world’s first free downloadable full-dome planetarium movie—conveys, through sparkling sights and sounds, the Universe revealed to us by science. Viewers can revel in the splendor of the worlds in the Solar System and our scorching Sun. From Earth to the Universe takes the audience out to the colorful birthplaces and burial grounds of stars, and still further out beyond the Milky Way to the unimaginable immensity of a myriad galaxies. Along the way, the audience will learn about the history of astronomy, the invention of the telescope, and today’s giant telescopes that allow us to probe ever deeper into the Universe.

Planetarium doors open at 7:45 p.m. and the program runs from 8 until 9 p.m. The show is free and open to all, but with limited seating we ask that you please reserve your ticket ahead of time.

Open Faculty Searches

October 3, 2025

UT Physics and Astronomy is a growing and vibrant department looking for two outstanding candidates to join our dynamic faculty.

We’re inviting applications for a tenure-track faculty position at the rank of Assistant Professor in the field of Computational Astrophysics. The department has active research programs in computational nuclear, neutrino, and gravitational wave astrophysics, which are complemented by its research programs in experimental nuclear astrophysics. Both programs benefit from extensive collaboration with research scientists at the nearby Oak Ridge National Laboratory, and from the world-class facilities there. We seek candidates to complement and expand these research efforts.

Applications are due on December 1, 2025. For additional information or questions, please contact Professor Tony Mezzacappa via email at mezz@ukt.edu.

The anticipated start date is August 1, 2026.

See the full position advertisement outlining all qualifications, expectations, and application instructions.

We are also inviting applications for a tenure-track faculty position at the rank of Assistant Professor in the field of Theoretical Particle Physics. We are particularly seeking applicants who can work closely with our existing particle physics program.

The department has broad research programs in experimental collider and neutrino physics, with leadership in the CMS Experiment, COHERENT, and efforts towards future colliders. We build neutron experiments searching for baryon number violation and have an active program in quantum computing for high energy physics. These programs benefit from extensive collaboration with research scientists at the nearby Oak Ridge National Laboratory, and from the leadership-class facilities there, such as the Spallation Neutron Source, the High Flux Isotope Reactor, and the Oak Ridge Leadership Computing Facility. We seek a candidate to complement, connect, and expand these research efforts.

Applications are due on December 1, 2025. For other questions, please contact Professor Yuri Efremenko at yefremen@utk.edu.

This position’s anticipated start date is August 1, 2026.

See the full position advertisement outlining all qualifications, expectations, and application instructions.

Vertex 2025 Comes to Rocky Top

September 30, 2025

When powerful particle beams collide, scientists rely on sophisticated detectors to track the paths of new particles created in the process. UT welcomed a group of those scientists to Vertex 2025, the International Workshop on Vertex Detectors.

The Vertex workshop is an annual forum for physicists and engineers who work in high-energy (elementary particle) and nuclear physics. They meet to share ideas on topics like detector technologies, tracking, electronics, and applications in quantum science and other fields. The focus, as the name implies, is on vertex detectors, whose reach extends beyond that of elementary particle physics.

Tracking Where Particles Start

Professor Stefan Spanier is part of UT’s particle physics group and was part of the meeting’s local organizing committee. He explained the role vertex detectors play, not only in fundamental science, but also in technologies that improve lives.

“When particle beams collide, many new particles are created,” he said. “This happens, for example, every 25 nanoseconds at the Large Hadron Collider (LHC) of CERN near Geneva during its operation. A vertex detector in high-energy physics is a highly accurate instrument designed to track the paths of charged particles immediately after they are produced in a collision. By tracing these paths backward, physicists can determine the origins of the particles, known as vertices.”

“The technology has been adapted for medical imaging, especially in advanced X-ray and nuclear medicine techniques,” he continued. “These detectors offer significant benefits, including high resolution, low radiation exposure, and energy-resolving capabilities.”

A large group of people standing in front of Ayres Hall on the University of Tennessee, Knoxville, campus

The importance of these instruments drew 68 researchers from Italy, Japan, the United Kingdom, France, Germany, Switzerland, the Czech Republic, and the United States to UT’s campus in mid-August for invited talks by field experts and individual contributions.

Physics Graduate Student Jesse Harris was among the students and postdoctoral associates who presented their work in a poster session held at Knoxville’s iconic Sunsphere.

“One of the highlights for me was presenting my poster,” Harris said. “I had the opportunity to discuss my work with experts in the field, receive valuable feedback, and understand how my research contributes to the broader context of high-energy physics at the Compact Muon Solenoid detector. The conversations I had with other students and researchers were incredibly inspiring. It was a fantastic opportunity to connect with the broader scientific community and build new relationships.”

Spanier said the workshop was valuable because scientists and students discussed vertex detector advances in a classroom-like setting, “while also having opportunities for dialogue and idea exchange outside a formal environment,” including plenty of breaks, social activities, a dinner, and a day of excursions that “helped build stronger relationships and encouraged networking.”

Along with Spanier, the organizing committee comprised three scientists from workshop co-sponsor Oak Ridge National Laboratory (ORNL): Mathieu Benoit, Marcel Demarteau, and Oskar Hartbrich. Spanier was quick to point out that the university’s Conference and Event Services staff was essential to the event’s success.

Harris also helped out with conference organization, which proved to be a valuable learning experience for a young scientist.

“I got to see the meticulous planning that goes into organizing a major scientific event,” he explained. “From coordinating with speakers and managing logistics to ensuring a seamless experience for all attendees, it really highlighted the importance of teamwork and attention to detail.”

Spanier said he received very positive feedback about the appeal of the university campus and its facilities. Several participants visited laboratories in the Science and Engineering Building as well as the Department of Nuclear Engineering, in addition to touring ORNL.

The next step for the organizers is putting together the workshop proceedings, which he said “will further promote UT as a vibrant place for research.”

Enhancing Thermoelectric Effects

September 29, 2025

UT’s physicists have helped develop a new approach to enhancing thermoelectric materials, energy converters that can turn waste heat into electricity or electricity into cooling and heating.

Thermoelectric materials use heat to create electricity by one of two avenues. The Seebeck effect moves current from the hot side to the cold side of a material. The temperature difference generates electricity. The lesser-studied Nernst effect creates voltage in a transverse direction but requires an external magnetic field. While this complicates its possible uses, this effect intrigues researchers because its geometry provides greater efficiency.

In this study, Dongliang Gong, Junyi Yang, Shashi Pandey, Dapeng Cui, Yang Zhang, and Jian Liu* were part of the team that synthesized an antiferromagnetic oxide material that could generate transverse voltage without the need for an external magnetic field. This anomalous Nernst effect (ANE) is the largest among the known magnetic oxides because of the magnetically broken symmetry. This opens a path to looking at other materials with similar symmetry configuration as candidates for greater thermoelectric efficiency.

Read the full research highlight from Argonne National Laboratory, or the original paper in Nature Communications.

*Dongliang Gong is a former postdoctoral research associate.

Junyi Yang completed his PhD in 2022 and is now working at Argonne National Laboratory.

Shashi Pandey graduated with a PhD in 2024 and is currently a postdoc at the University of Michigan.

Dapeng Cui is a postdoctoral research associate.

Yang Zhang is an assistant professor of physics. Jian Liu is a professor of physics.

Lunch and Learn with the Vol Edge!

September 9, 2025

Orange, smokey and white text graphics reading The Vol Edge Lunch and Learn

In this special edition of the Vol Edge Lunch and Learn series, physics students will explore the skills employers are looking for and how to set yourself apart as a candidate. Attendees get a free physics and astronomy T-shirt!

RSVP Here!

Monday 9/15

12-2 PM

Nielsen Physics 307

A Night at the Planetarium: Firefall

September 2, 2025

An image of comets and asteroids advertising the planetarium show Firefall

Throughout Earth’s violent history, impacts from comets and asteroids have mercilessly shaped its surface. The ancient barrage continues today, from harmless meteors (those brilliant streaks in the night sky) to mountain-sized boulders wandering perilously close to our home planet. Terrifying and majestic, these invaders from space are capable of utter destruction, yet they have delivered life-giving water and most of the organic materials necessary for life. Life on Earth owes its very existence to these denizens of the solar system, yet it could all be wiped out in an instant.

This ceaseless Firefall is our only tangible connection to the universe beyond and is an ever-present reminder of our own humble beginnings in the hostile environment of space. Join us on Friday, September 12, for the amazing planetarium show Firefall in Room 108 of the Nielsen Physics Building.

Doors open at 7:45 p.m. and the screening runs from 8 until 9 p.m. The show is free and open to all, though viewers under 18 should be accompanied by a parent or legal guardian. Seating is limited, so reserve your tickets now!

Research Overview: The Power of RIXS

August 28, 2025

Courtesy of Bains Professor Steven Johnston and students Jinu Thomas and Debshikha Banerjee

Quantum materials—systems whose properties are dominated by quantum mechanical many-body effects—represent one of the most exciting frontiers of condensed matter physics. They also have the potential to revolutionize technology with applications in superconductors, magnets, and sensors.

In these systems, it is common for different degrees of freedom like spin, charge, orbital, and lattice vibrations to become intricately entangled, making it difficult to identify which is the driver of a given phenomenon. This entanglement makes quantum materials hard to model, but it also produces a wide range of exotic phenomena, including high-temperature superconductivity, various types of density waves, topological states, and more. Notably, the Bains Professor Steven Johnston’s research group has long been interested in how electrons couple to atomic vibrations and how this interaction can influence the properties of these materials.

Advanced experimental and numerical techniques are required to unravel the complex behavior present in quantum materials. Among them, resonant inelastic x-ray scattering (RIXS) has emerged as a powerful spectroscopic tool due to its ability to simultaneously probe spin, charge, orbital, and lattice excitations in a single experiment. A recent perspective piece published in Physical Review X by Johnston and Adjunct Professor Mark Dean, along with their colleagues, sheds light on applications of RIXS in quantum materials. More recently, members of Johnston’s group have published a study in Physical Review Letters, presenting state-of-the-art calculations for RIXS response for a correlated quantum material with strong interactions to phonon modes via a novel kinetic energy coupling mechanism.

First author and PhD student Debshikha Banerjee, together with Jinu Thomas, Alberto Nocera (University of British Columbia), and Johnston, used the density matrix renormalization group (DMRG) to predict the RIXS spectra for a one-dimensional Hubbard chain coupled with Su-Schrieffer-Heeger (SSH)-like electron-phonon coupling. This model has established itself for studying chain systems like Sr₂CuO₃, which has long served as a platform for studying quantum magnetism in low-dimensional systems.

Most studies of electron-phonon coupling have focused on simplified models (e.g., Holstein or Fröhlich), where coupling is between electron density and lattice displacements. In contrast, the SSH model captures lattice vibrations that alter atomic bond lengths, an interaction present in all materials. SSH electron-phonon interactions have gained widespread interest in recent years following predictions that SSH interactions can contribute to high-temperature superconductivity. SSH interactions have also been tied to topological edge states, a topic of interest in recent years. To test these theoretical claims, the community needs experimental protocols to identify the existence of SSH interaction in materials. Banerjee et al.’s work demonstrates how RIXS can be exploited to identify and quantify SSH interactions in quantum materials.

This study builds on a recent work led by PhD student Jinu Thomas and the same team, published in Physical Review X, which has advanced the state-of-the-art modeling of lattice excitations in RIXS.