A puzzling form of superconductivity that arises only under strong magnetic fields has been mapped and explained by a research team of UMD, NIST and Rice University including  professor of physics and astronomy at Rice University. Their findings,  published in Science July 31, detail how uranium ditelluride (UTe2) develops a superconducting halo under strong magnetic fields. 

Traditionally, scientists have regarded magnetic fields as detrimental to superconductors. Even moderate magnetic fields typically weaken superconductivity, while stronger ones can destroy it beyond a known critical threshold. However, UTe2 challenged these expectations when, in 2019, it was discovered to maintain superconductivity in critical fields hundreds of times stronger than those found in conventional materials. Image by Sylvia Klare Lewin, Nicholas P Butch/ NIST & UMD

“When I first saw the experimental data, I was stunned,” said Andriy Nevidomskyy, a member of the Rice Advanced Materials Institute and the Rice Center for Quantum Materials. “The superconductivity was first suppressed by the magnetic field as expected but then reemerged in higher fields and only for what appeared to be a narrow field direction. There was no immediate explanation for this puzzling behavior." 

Superconducting resurrection in high fields

This phenomenon, initially identified by researchers at the University of Maryland Quantum Materials Center and the National Institute of Standards and Technology (NIST), has captivated physicists worldwide. In UTe2, superconductivity vanished below 10 Tesla, a field strength that is already immense by conventional standards, but surprisingly reemerged at field strengths exceeding 40 Tesla. 

This unexpected revival has been dubbed the Lazarus phase. Researchers determined that this phase critically depends on the angle of the applied magnetic field in relation to the crystal structure. 

In collaboration with experimental colleagues at UMD and NIST, Nevidomskyy decided to map out the angular dependence of this high-field superconducting state. Their precise measurements revealed that the phase formed a toroidal, or doughnutlike, halo surrounding a specific crystalline axis. 

“Our measurements revealed a three-dimensional superconducting halo that wraps around the hard b-axis of the crystal,” said Sylvia Lewin of NIST, a co-lead author on the study. “This was a surprising and beautiful result.”

Building theory to fit halo

To explain these findings, Nevidomskyy developed a theoretical model that accounted for the data without relying heavily on debated microscopic mechanisms. His approach employed an effective phenomenological framework with minimal assumptions about the underlying pairing forces that bind electrons into Cooper pairs. 

The model successfully reproduced the nonmonotonic angular dependence observed in experiments, offering insights into how the orientation of the magnetic field influences superconductivity in UTe2. 

Deeper understanding of interplay

The research team found that the theory, fitted with a few key parameters, aligned remarkably well with the experimental features, particularly the halo’s angular profile. A key insight from the model is that Cooper pairs carry intrinsic angular momentum like a spinning top does in classical physics. The magnetic field interacts with this momentum, creating a directional dependence that matches the observed halo pattern. 

This work lays the foundation for a deeper understanding of the interplay between magnetism and superconductivity in materials with strong crystal anisotropy like UTe2. 

“One of the experimental observations is the sudden increase in the sample magnetization, what we call a metamagnetic transition,” said NIST’s Peter Czajka, co-lead author on the study. “The high-field superconductivity only appears once the field magnitude has reached this value, itself highly angle-dependent.” 

The exact origin of this metamagnetic transition and its effect on superconductivity is hotly debated by scientists, and Nevidomskyy said he hopes this theory would help elucidate it. 

“While the nature of the pairing glue in this material remains to be understood, knowing that the Cooper pairs carry a magnetic moment is a key outcome of this study and should help guide future investigations,” he said.

Co-authors of this study include Corey Frank and Nicholas Butch from NIST; Hyeok Yoon, Yun Suk Eo, Johnpierre Paglione and Gicela Saucedo Salas from UMD; and G. Timothy Noe and John Singleton from the Los Alamos National Laboratory. This research was supported by the U.S. Department of Energy and the National Science Foundation.

 Original article: https://news.rice.edu/news/2025/superconductivitys-halo-rice-theoretical-physicist-helps-map-rare-high-field-phase

The University of Maryland has named Gretchen Campbell, an internationally recognized researcher and national leader in advancing the field of quantum science, as associate vice president for quantum research and education, effective July 13, 2025.

In this newly established position, Campbell will collaborate with faculty, students and campus partners to further UMD's prominence in quantum science and technology. Her position will focus on shaping UMD’s strategic vision for quantum research; advancing Gov. Wes Moore’s vision for transforming the state and region into the global Capital of Quantum; expanding quantum curricula for K-12 through graduate programs; and forging strategic partnerships that position Maryland at the forefront of quantum research, education and innovation.Gretchen Campbell

"Dr. Campbell brings an exceptional combination of scientific expertise, national leadership and deep experience in building partnerships across academia, government and industry," said Senior Vice President and Provost Jennifer King Rice. "Her leadership will be instrumental in advancing Maryland’s bold vision for quantum research and education, and strengthening our position as a global hub for quantum innovation."

Campbell’s appointment comes on the heels of two recent major developments that helped solidify UMD as a global leader in quantum science and technology: the launch of the $1 billion “Capital of Quantum” initiative announced by Gov. Moore and the establishment of the Capital Quantum Benchmarking Hub to be located at the university’s Applied Research Laboratory for Intelligence and Security. These initiatives reinforce UMD's status as a world leader in quantum, building on more than 35 years of pioneering research, key collaborations and a commitment to education and economic development.

“The University of Maryland boasts a remarkable legacy in leading quantum exploration, and now is the pivotal moment to amplify our role in this rapidly expanding field and cultivate a quantum-ready workforce,” said Vice President for Research Patrick O’Shea. “With Dr. Campbell at the helm, I am absolutely confident that we will not only achieve our ambitious goals but also soar to new heights.”

Campbell assumes this new role in the Division of Research following a detail assignment to the White House Office of Science and Technology Policy (OSTP), where she most recently served as assistant director for quantum information science and director of the National Quantum Coordination Office. In that position, she coordinated federal quantum efforts across government, industry and academia and co-chaired the National Quantum Initiative Advisory Committee, providing insight and recommendations to the President, Congress and the National Science and Technology Council.

In addition to her work with OSTP, Campbell held multiple leadership roles at the National Institute of Standards and Technology (NIST), where she led the Laser Cooling and Trapping Group in the Quantum Measurement Division. From 2016 to 2025, she was co-director of the Joint Quantum Institute, a partnership between UMD, NIST and the Laboratory for Physical Sciences, and she has been an adjunct professor in UMD's Department of Physics since 2009.

“I’ve been fortunate to be part of Maryland’s quantum community for many years,” Campbell said. “Stepping into this new role, I’m excited to help build on that foundation and continue advancing our leadership alongside our outstanding faculty, students and partners.”

A pioneering experimental physicist, Campbell’s research includes work on Bose-Einstein condensates, ultra-precise atomic clocks and the creation of the first atomtronic circuits. She is a Fellow of the American Physical Society and the recipient of numerous honors, including the Presidential Early Career Award in Science and Engineering, the Arthur Flemming Award that honors outstanding federal employees, the Maria Goeppert Mayer Award from the American Physical Society and the International Union of Pure and Applied Physics’ Young Scientist Prize.

Campbell earned her Ph.D. from the Massachusetts Institute of Technology and her undergraduate degree from Wellesley College.

Original story: https://umdrightnow.umd.edu/university-of-maryland-appoints-renowned-physicist-to-lead-quantum-research-and-education

Physics graduates Jade LeSchack, Elaine Taylor and Jeffrey Wack have received prestigious National Science Foundation (NSF) Graduate Research Fellowships, which recognize outstanding graduate students in science, technology, engineering, and mathematics.

This year’s awardees from the University of Maryland’s College of Computer, Mathematical, and Natural Sciences (CMNS) are:

• Dean Calhoun, Ph.D. student in atmospheric and oceanic science
• Zora Che, Ph.D. student in computer science
• Yuran Ding, Ph.D. student in computer science
• Ethan Heldtman (B.S. '24, atmospheric and oceanic science)
• Jade LeSchack (B.S. '25, physics; B.S. '25, mathematics), University of Southern California
• George Li (B.S. ’24, mathematics; B.S. ’24, computer science), Carnegie Mellon University
• Maria Nikolaitchik (B.S. '24, atmospheric and oceanic science; B.S. '24, mathematics)
• Tesia Shi (B.S. ’23, biological sciences; B.S. ’23, psychology)
• Jonathan Starfeldt, Ph.D. student in atmospheric and oceanic science
• Logan Stevens (B.S. '23, computer science, B.A. '23, theater), Ph.D. student in computer science at UMD
• Elaine Taylor (B.S. '23, physics and astronomy), Stanford University
• Jeffrey Wack (B.S. '22, physics; B.S. '22, mathematics), Caltech
• Adam Yang, computer science major
• Grant Yang (B.S. ’23, biological sciences), Harvard University
• Mary Yilma (B.S. ’21, mathematics; B.S. ’21, economics), Massachusetts Institute of Technology

The NSF Graduate Research Fellowship Program helps ensure the quality, vitality, and strength of the United States' scientific and engineering workforce. The five-year fellowships provide three years of financial support, including an annual stipend of $37,000.

Since 1952, NSF has funded over 60,000 Graduate Research Fellowships out of more than 500,000 applicants. At least 42 fellows have gone on to become Nobel laureates, and more than 450 have become members of the National Academy of Sciences.

Original story: https://cmns.umd.edu/news-events/news/15-nsf-graduate-research-fellowships-2025

Mohammad Hafezi has received a Humboldt Research Award, which acknowledges his history of impactful research and supports visiting Germany to collaborate with colleagues there. Each year, the Alexander von Humboldt Foundation gives the award, which is supported by the Federal Foreign Office and the Federal Ministry of Education and Research in Germany, to no more than 100 researchers from around the world.

“I’m honored to receive this award,” says Hafezi, who is also a Minta Martin professor of electrical and computer engineering and physics at the University of Maryland and a senior investigator at the National Science Foundation Quantum Leap Challenge Institute for Robust Quantum Simulation. “It's a great opportunity. The Humboldt Foundation has a long history of funding exceptional and interesting scientific work.”Mohammad Hafezi

Recipients of the award are academic researchers who can work in any discipline but who primarily live and work outside of Germany. Each candidate is nominated for consideration by a researcher at a German research institute, and the foundation selects recipients whose work has had a significant and lasting impact beyond their field of specialization.

Hafezi leads a research group that explores quantum behaviors resulting from the interplay of light and matter through both theoretical and experimental projects. His group tackles diverse topics like quantum optics and quantum simulation, which are vital to advancing quantum computing, sensing, and communication technologies. 

One subject Hafezi’s group is currently investigating is the physics of correlated electronic systems—materials and devices in which electrons are group players instead of individuals with independent quantum interactions. This line of research is building on decades of work investigating individual particles of light—photons—interacting with individual electrically-charged particles, often electrons. The physics of individual electrons interacting with light is utilized in a variety of technologies such as LEDs, laser projectors and quantum computers. But there is much more research to be explored, and potentially new technologies to invent, based on correlated electronic systems.

As part of the award, each recipient is invited to visit Germany and collaborate with colleagues at a German research institution. Hafezi is planning to use the opportunity to work in person with colleagues at the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, which is a global hub for cutting-edge research into correlated electronic systems. In particular, Angel Rubio and Andrea Cavalleri, who both work at the institute, are studying exciting topics like the nearly alchemical ability of light to make certain materials a superconductor or to make an existing superconductor more robust.

Together Hafezi and his colleagues in Hamburg will adapt and build on existing techniques and ideas, such as methods of using light to manipulate quantum states—quantum-optical control techniques—and frameworks from quantum information science developed to build quantum computers. Hafezi hopes that working together in person will produce ideas that they aren’t currently considering.

“I find it deeply compelling to investigate whether quantum-optical control techniques can be leveraged to probe, manipulate, and engineer correlated electronic systems in novel ways,” Hafezi says. “We may have to go back to the drawing board and then write things from first principles and come up with other models that can capture such many-body physics. So there is much work that has to be done.”

He says visiting Germany is an incredible opportunity for organic interactions that allow them to more easily connect and build on each other’s ideas.

“Nothing replaces in-person collaboration.” Hafezi says. “Given the fantastic theoretical work by Angel Rubio and the groundbreaking experimental research led by Andrea Cavalleri, I’m thrilled to deepen our collaboration and explore new directions together.”

Original story by Bailey Bedford: https://jqi.umd.edu/news/hafezi-receives-humboldt-research-award