Research, teaching and outreach in Physics at UW–Madison
Awards and Honors
Mark Saffman wins Bell Prize
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This post is derived from content originally published by the University of Toronto
Mark Saffman
Congrats to Mark Saffman, the Johannes Rydberg Professor of Physics and director of the Wisconsin Quantum Institute, on earning the ninth Biennial John Stewart Bell Prize for Research on Fundamental Issues in Quantum Mechanics and Their Applications.
He shares the prize with Antoine Browaeys (CNRS, Université Paris-Saclay) and Mikhail Lukin (Harvard) for their pioneering contributions to quantum simulation and quantum computing with neutral atoms in optical tweezer arrays, including the development of large-scale programmable arrays for scalable quantum computation. The prize will be given at the eleventh international conference on Quantum Information and Quantum Control, University of Toronto.
Saffman’s career-spanning work was also recognized last month with the American Physical Society’s Ramsey Prize in AMO Physics and in Precision Tests of Fundamental Laws and Symmetries, a prize he shares with Browaeys.
The John Stewart Bell Prize for Research on Fundamental Issues in Quantum Mechanics and their Applications (short form: “Bell Prize”) was established in 2009, and is awarded every other year, for significant contributions first published in the preceding 6 years. The award is meant to recognize major advances relating to the foundations of quantum mechanics and to the applications of these principles – this covers, but is not limited to, quantum information theory, quantum computation, quantum foundations, quantum cryptography, and quantum control. The award is not intended as a “lifetime achievement” award, but rather to highlight the continuing rapid pace of research in these areas, and the fruitful interplay of fundamental research and potential applications. It is intended to cover even-handedly both of these aspects, and to include both theoretical and experimental contributions.
Francis Halzen wins 2026 APS Medal for Exceptional Achievement in Research
Mark Saffman, the Johannes Rydberg Professor of Physics and director of the Wisconsin Quantum Institute, won the American Physical Society’s 2026 Norman F. Ramsey Prize in Atomic, Molecular, and Optical Physics, and in Precision Tests of Fundamental Laws and Symmetries.
The Ramsey prize recognizes outstanding accomplishments in the two fields of Norman Ramsey: atomic, molecular, and optical (AMO) physics; and precision tests of fundamental laws and symmetries. Saffman won “for seminal developments of quantum information processing with neutral atoms that allow the investigation of many-body problems that are intractable by classical computing.” He shares the prize with Antoine Browaeys at the Institut d’Optique in France.
Mark Saffman
Saffman joined the UW–Madison physics faculty in 1999 with ideas for his research program but struggled to acquire enough funding. Then, he started reading theory papers about the relatively new field of quantum computing and how to develop qubits, or quantum bits.
“This was in an era when people were proposing all these different ideas for qubits,” Saffman says. “I read this paper about using Rydberg gates to entangle atomic qubits and thought, ‘This looks interesting, let’s do that.’ That was the smartest decision I ever made in my career.”
An atom can be induced into a Rydberg state by a strong laser, when one of its outer shell electrons is excited into a very high energy state. The atom is effectively much larger than usual, and can lead to interesting quantum properties. Relatively inexperienced in experimental atomic physics, Saffman approached Thad Walker, a professor in the department and an expert on how to laser cool atoms, about collaborating. A decade later, they had their major success: a Rydberg blockade.
“The basic interaction is that you excite one atom to a Rydberg state and then you cannot excite a second one close by,” Saffman says. “That blockade interaction lies behind the ability to do a logic gate — a CNOT gate — and entangle two qubits.”
A year later, Saffman and Walker demonstrated the first CNOT gate for atomic qubits. These qubits, also called neutral atom qubits, quickly are now one of the leading platforms for achieving fault tolerant quantum computing.
Over the next decade Saffman started to realize that building a fully functional quantum computer was not just a scientific effort, it was a major engineering effort, one that was likely outside the scope of an academic research group.
“It became clear to me that to compete at the forefront, I needed more resources. I wanted to go faster,” Saffman says. “So, I ended up joining forces with ColdQuanta (now Infleqtion), an existing small cold atom sensing and components company .”
The glow of red and green lasers and an array of supporting electronics fill the Saffman lab | Jacob Scott, PhD’25
Saffman brought his quantum computing ideas to the company as Chief Scientist for Quantum Information at Colorado-based Infleqtion in 2018, and the company now has a satellite office in Madison.
The partnership with Infleqtion did, in fact, accelerate Saffman’s research. In 2022, his group, including long-time scientist and group member Trent Graham, co-authored a paper with engineers at Infleqtion where they demonstrated the first quantum algorithm to be run on an atomic quantum computer. It was a huge proof of principle and significant step forward in the field.
Quantum information research has emerged as a major topic within the AMO physics community. At UW–Madison, Saffman has been a key player in that shift. In 2019, he helped develop the Wisconsin Quantum Institute, an interdisciplinary effort of all quantum information science and engineering researchers on campus. That same year, he was named the institute’s director.
“UW–Madison was one of the first places to have multiple serious efforts in qubits: Thad and I pioneered neutral atoms, (physics professor) Mark Eriksson pioneered silicon spin qubits, (physics professor) Robert McDermott has superconducting qubits,” Saffman says. “Now, a huge fraction of new faculty coming out of academia and starting their own groups are working in quantum information-related science and engineering, including many of our new faculty. The state of quantum computing at UW–Madison is very strong.”
Deniz Yavuz elected Fellow of the American Physical Society
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Deniz Yavuz
Congratulations to Prof. Deniz Yavuz, who was elected a 2025 Fellow of the American Physical Society!
He was elected “for outstanding experimental and theoretical contributions to nanoscale localization of atoms with electromagnetically induced transparency and collective radiation effects in atomic ensembles,” and nominated by the Division of Atomic, Molecular & Optical Physics (DAMOP).
APS Fellowship is a distinct honor signifying recognition by one’s professional peers for outstanding contributions to physics. Each year, no more than one half of one percent of the Society’s membership is recognized by this honor.
Congrats to Vladimir Zhdankin, assistant professor of physics, on earning a Department of Energy Early Career award! The five-year award will fund his research on energy and entropy in collisionless, turbulent plasmas.
Systems in equilibrium are easy to describe, but often the most interesting questions in nature are complex and dynamic. Most plasmas, including astrophysical ones and manmade ones on earth, are not in equilibrium, so they are more difficult to characterize. Zhdankin’s research is working toward a more universal understanding of non-equilibrium plasmas, in the form of mathematical equations that can then be broadly applied.
“We think that our understanding of plasmas isn’t finished yet, and there are still some basic ingredients in the statistical mechanics which, once we understand better, we’ll have a more predictive framework for how plasmas should behave,” Zhdankin says.
Collisionless plasmas have a low enough particle density where the particles largely flow without bumping into each other. Instead, their trajectories are controlled by the electric and magnetic field, which leads to a generally chaotic flow, like the rapids of a river. It is that dynamic turbulence that causes these plasmas to be non-equilibrium, leading to interesting, if not straightforward, properties.
“In these systems, energy is conserved — it has to be,” Zhdankin says. “But we don’t quite have a handle on what’s happening with the entropy. We have reason to believe it’s increasing, consistent with the second law of thermodynamics, but it doesn’t seem to reach a maximum.”
Zhdankin’s goal is to better understand the energy and entropy in these complex plasmas through “particle-in-cell” simulations, where tens of billions of plasma particles — electrons and protons — are simulated in a small box, then manipulated in various ways.
“We imagine stirring the plasma to make it more turbulent and putting some energy into it, and then we want to see how it heats up and how the particles achieve higher energies,” Zhdankin says. “What if we increase or decrease the size of the box? Make the magnetic field stronger? Make the particles collide a little bit?”
The simulations can then be compared to real-world data, including measurements of the solar wind or laboratory plasmas. An ideal outcome would be obtaining formulae that better describe these complex, turbulent plasmas and can be applied across a broad range of systems, from laboratory experiments to the accretion flows of black holes.
“And there’s a chance we’re just not going to be able to get something predictive out of this work, if there’s just too big of a landscape of possibilities,” Zhdankin says. “But this topic, I consider it one of the most fundamental ones that could be studied in plasma physics.”
Hilldale Undergraduate Award Winners in Physics
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Four physics majors have earned 2025 Hilldale Fellowships. They are:
Ruben Aguiló Schuurs, Computer Sciences and Physics major, working with Mark Saffman
Zijian Hao, Astronomy – Physics and Physics major, working with Paul Terry (Physics)
Nathaniel Tanglin, Astronomy – Physics and Physics major, working with Elena D’Onghia (Astronomy)
Michael Zhao, AMEP and Physics major, working with Saverio Spagnolie (Mathematics)
Additionally, Qing Huang, a Data Science, Information Science, and Statistics major working with Gary Shiu (Physics) also earned an award.
The Hilldale Undergraduate/Faculty Research Fellowship provides research training and support to undergraduates. Students have the opportunity to undertake their own independent research project under the mentorship of UW–Madison faculty or research/instructional academic staff. Please Note: Graduate students are ineligible to serve as the project advisor. Approximately 97 – 100 Hilldale awards are available each year.
The student researcher receives a $4,000 stipend (purpose unrestricted) and the faculty/staff research advisor receives $1,000 to help offset research costs (e.g., supplies, books for the research, student travel related to the project). The project advisor can decline the $1,000 if it is not needed to support the student’s research. Declined project advisor funds are pooled to offer additional Hilldale Fellowships.
Roman Kuzmin earns NSF CAREER Award
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Roman Kuzmin
Congrats to Roman Kuzmin, the Dunson Cheng Assistant Professor of Physics, for being selected for an NSF CAREER award. The 5-year award will support Kuzmin and his group’s research on understanding fluxonium qubits and how their properties can be used to simulate the collective behavior of quantum materials.
Superconducting qubits are one promising technology for quantum computing, and the best-studied type is the transmon. Kuzmin’s work will investigate the fluxonium type, which he expects to be an improvement over transmons because they have demonstrated higher coherence, and their ground and first excited state are better separated from other energy levels.
“These properties make fluxonium behave similar to a magnetic moment, or like a magnetic atom, which we can fabricate in the lab and tune its properties,” Kuzmin says. “Things become interesting when interactions are very strong, and you need to involve many-body physics to describe them. We plan to build circuits which recreate the behavior of these complicated systems so that we have better control and can study multiple collective phenomena that appear in materials with magnetic impurities.”
In the lab, this research will be explored by building circuits with fluxonium qubits, capacitors, and inductors, which are further combined into more complicated circuits. The circuits will be used to test theoretical predictions of such behaviors as quantum phase transitions, entanglement scaling, and localization.
In addition to an innovative research component, NSF proposals require that the research has broader societal impacts, such as developing a competitive STEM workforce or increasing public understanding of science. Kuzmin plans to expand his work in the department’s Wonders of Physics program. This past February, he helped build a wave machine (with Steve Narf) to visually demonstrate patterns of interference, and he performed in all eight shows. His group has also participated in TeachQuantum, a summer research program for Wisconsin high school teachers run through HQAN, the NSF-funded Quantum Leap Challenge Institute that UW–Madison is a part of.
“One of the goals of this proposal is to introduce more quantum physics to the annual Wonders of Physics show; another is to provide hands-on training for high school teachers in my lab,” Kuzmin says. “Together, these activities will increase K-12 students’ engagement with quantum science and technology.”
The Faculty Early Career Development (CAREER) Program is an NSF-wide activity that offers the Foundation’s most prestigious awards in support of early-career faculty who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization. Activities pursued by early-career faculty should build a firm foundation for a lifetime of leadership in integrating education and research.
Four professors earn promotions, including tenure for Ke Fang
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Congratulations to Associate Professor Ke Fang on her promotion with tenure, to Professor Justin Vandenbroucke on his promotion to full professor, and to Profs. Dan Hooper and Britton Plourde who were both granted tenure!
Ke Fang
Prof. Fang is an experimental particle astrophysicist and WIPAC investigator who studies the origins of subatomic particles and their fundamental nature by detecting messengers from throughout the universe. She has made major contributions to the analysis of data from the High Altitude Water Cherenkov (HAWC) Observatory, the IceCube Observatory and the NASA Fermi satellite.
In 2021, Fang received the Shakti P. Duggal Award for Early Career Contributions in Cosmic Ray Physics. In 2023, she received the NSF CAREER award. In 2024, she was named a Sloan Fellow. Later that year, she was named the inaugural recipient of the Bernice Durand Faculty Fellowship, a departmental award named in honor of Durand, one of the first two women faculty members in the UW–Madison physics department. She also served as the US spokesperson for HAWC in 2023-2025.
“Ke Fang is one of the most impactful astroparticle phenomenologists of her generation,” says physics department chair and professor Kevin Black. “Her work is highly original and broad with strong implications for the emerging area of multi-messenger astronomy and particle astrophysics.”
Justin Vandenbroucke
Prof. Vandenbroucke is also a WIPAC investigator and experimental particle astrophysicist. He joined the department in 2013. His main research focus is in multi-messenger astrophysics, including neutrino astronomy, gamma-ray astronomy, and cosmic rays. He is a member of the IceCube collaboration and the Cherenkov Telescope Array Observatory consortium and is an affiliate member of the Fermi LAT and VERITAS collaborations.
Vandenbroucke was previously promoted to associate professor with tenure in 2019. He was named a Vilas Associate from 2023-2025, and was a co-recipient of UW2020 awards in 2018 and 2020. He also leads the Distributed Electronic Cosmic-Ray Observatory (DECO), a citizen science project that enables users around the world to detect cosmic rays and other energetic particles with their cell phones and tablets.
“Justin Vandenbroucke is an outstanding experimentalist who, at the same time, develops creative and challenging data analysis projects that have led to scientific results published in highly cited papers,” Black says. “He does this in two different fields, gamma-ray and neutrino astrophysics, and is a leader in both.”
Dan Hooper
Prof. Hooper, PhD’03 was named the director of WIPAC and joined the physics faculty as a full professor in 2024. He is a theoretical particle astrophysicist whose research focuses on the interface between particle physics and cosmology. His work has spanned the areas of dark matter, high-energy neutrino astronomy, gamma-ray astronomy and cosmic-rays. He is the author of several books and co- hosts the physics podcast “Why This Universe?” breaking down some of some of the biggest ideas in physics into easily digestible chunks.
“Dan Hooper is a singular figure in his field, a stand-out leader in terms of scientific impact whose ideas cast a wide influence on the study of high energy theory, dark matter phenomenology, collider physics, astroparticle physics, and the direct experimental and observational search for dark matter,” Black says.
Britton Plourde
Prof. Plourde joined the department as a full professor in 2024 from Syracuse University. He is an experimental condensed matter physicist who studies superconducting quantum circuits. He is currently on a half-time leave at UW–Madison and works with Qolab, a quantum computing startup company based in Madison. Plourde was elected a Fellow of the American Physical Society in 2024 in the Division of Quantum Information, and in 2023 was elevated to Fellow of the Institute of Electrical and Electronics Engineers.
“Britton Plourde is internationally recognized for his contributions in the field of low-temperature physics and superconducting quantum circuits,” Black says. “He has made significant contributions in the field of superconducting quantum computing and is best known in the community for his works on superconducting qubits, left-handed and quantum metamaterials, and, more recently, for studies of decoherence sources and suppression of errors in superconducting quantum circuits.”
Natasha Kassulke and Alisa King-Klemperer contributed to this story
