PRB Highlights Work of Das Sarma and Hwang

To mark the 50th anniversary of Physical Review B, editors selected “milestone” papers that have made lasting contributions to condensed matter physics, including one co-written by Distinguished University Professor Sankar Das Sarma.pr50 social cropped ratio 0

Das Sarma wrote the selected paper, Dielectric function, screening, and plasmons in two-dimensional graphene, with Euyheon Hwang. Hwang earned his doctorate in 1996 under Das Sarma, and after appointments as a UMD research associate and assistant research scientist, accepted a faculty post at Sungkyunkwan University (SKKU) in South Korea.  He is one of about 100 of Das Sarma’s students and postdocs who have gone on to faculty appointHwang DasSarma 2003Euyheon Hwang (seated, yellow shirt) and Sankar Das Sarma (red shirt) with CMTC colleagues in 2003.ments.

Hwang and Das Sarma have written about 120 articles together, including 88 papers in PRB from 1994 to 2019.

The milestone paper was published in 2007 and has 1,744 citations. In it, the authors developed a many body theory for the dynamical dielectric function of doped graphene at an arbitrary wave vector and frequency.   The dielectric function directly determines many physical properties, including electrical and optical properties.  This ‘milestone’ publication by Hwang and Das Sarma has been instrumental not only in the development of the fundamental physics of graphene, but has also ushered in the technological field of ‘graphene plasmonics’ which is being widely pursued worldwide for practical engineering use in optics and photonics.

Das Sarma, the Richard E. Prange Chair in Physics, is a Distinguished University Professor, a Fellow of the Joint Quantum Institute, and the director of the Condensed Matter Theory Center. He is internationally known for his work on topological quantum computation, Majorana physics, spin quantum computation, many body phenomena, quantum localization and nonequlibrium statistical mechanics, and has recently entered into the study of twisted bilayer graphene and higher-order topological systems. Google Scholar counts 90,227 citations and calculates an h-index of 124.



(link sends e-mail)

Nick Butch Honored by NIST

Adjunct Associate Professor Nicholas Butch will receive the National Institute of Standards and Technology’s 2020 Samuel Wesley Stratton Award "for pioneering research into the exotic physics and extremely high-field re-entrant superconductivity in uranium ditelluride." The Stratton Award, named after the first director of the National Bureau of Standards, as NIST was then known, recognizes an unusually significant research contribution to science or engineering that merits the acclaim of the scientific world and supports NIST’s mission objectives.Nick ButchNick Butch

Butch, a physicist at NIST’s Center for Neutron Research, is a member of the Quantum Materials Center (QMC). His first UMD appointment was as a Rolfe Glover Postdoctoral Fellow in 2008.

Among Butch’s research pursuits are quantum materials and superconductivity. In 2019, he and collaborators discovered superconductivity in the material uranium ditelluride (UTe2) and then described a remarkable quirk: high magnetic fields seem to stabilize, not destroy, its superconducting state. This resilience could make UTe2 a promising material for use in quantum computers.

Earlier in 2020, Butch and collaborators also announced that experiments with UTe2 revealed that it might contain the long-sought Majorana fermion.

Butch earned his Ph.D. in 2008 at the University of California, San Diego. In 2017, he received a Presidential Early Career Award for Scientists and Engineers (PECASE), the highest honor bestowed by the United States government on science and engineering professionals in the early stages of their research careers.

PRA Highlights Work of Ian Spielman

A paper coauthored by Adjunct Professor and JQI Fellow Ian Spielman in 2011 has been highlighted by the journal Physical Review A as part of its 50th anniversary celebration—one of only 26 that the journal plans to highlight in its “anniversary milestones” collection.

The collection comprises papers published in the journal “that have made important contributions to atomic, molecular, and optical physics and quantum information by announcing significant discoveries or by initiating new areas of research.” Highlighting these notable papers is part of the American Physical Society’s celebration of the splitting of the journal Physical Review into four journals, Physical Review A-D, that each cover different specialized physics content.pr50 social cropped ratio 0

In Spielman’s paper, which was also highlighted by Google Scholar Metrics in 2014, he and his colleagues proposed an experimental setup to create quantum interactions called Rashba and Dresselhaus spin-orbit coupling for an atomic Bose-Einstein condensate. Spin-orbit coupling is an interaction where the properties of spin—an attribute of quantum objects related to rotation and magnetism—and momentum become tied together. The phenomenon helps stabilize the states against quantum disturbances and plays an important role in materials, like topological insulators, that are of theoretical and technological interest.

The paper describes how experiments can create the desired coupling for electrically neutral rubidium atoms by using lasers, and it also provides an intuitive, visual framework for understanding such experiments as an alternative to the prior, more-abstract mathematical description that researchers were using.

“What I think this proposal really did is change the language that we used to think about engineering spin-orbit coupled systems,” says Spielman. “This paper provides a super-visual construction that you can do on the fly in your head to know about what's going to happen in an experiment.”

In the proposal, several lasers are set up so that they interact with the atoms simultaneously to create the appropriate quantum state with the desired coupling. The paper presented the physics in the experiments in terms of how the photons that make up the lasers contribute momentum to the atoms.

According to Xiangyu Yin, the associate editor of Physical Review A, Spielman’s paper “inspired several successful experimental realizations of spin-orbit coupled neutral atoms in two dimensions, paving the way for exploring exotic quantum phases in a new platform.”

In addition to experiments by others, Spielman’s own research group at JQI has built on this work and he says that he hopes that similar experiments with atoms other than rubidium will open opportunities to explore even more new physics. 

Reference Publication: 
"Realistic Rashba and Dresselhaus spin-orbit coupling for neutral atoms," D.L. Campbell, G. Juzeliunas, Ian B. Spielman, Physical Review A, 84, 025602 (2011)
Original story by Bailey Bedford, This email address is being protected from spambots. You need JavaScript enabled to view it.
(link sends e-mail)

Monroe Elected OSA Fellow

Christopher Monroe has been elected as a Fellow of The Optical Society (OSA)(link is external). He is one of 118 OSA members to be selected this year.

Monroe is also a Distinguished University Professor, the Bice Zorn Professor of Physics, and a fellow of the Joint Quantum Institute and the Joint Center for Quantum Information and Computer Science. He leads an experimental research group that masterfully manipulates the delicate interactions of light and ions. Their experiments span everything from simulating wormholes to pushing the frontiers of quantum computing.

Monroe also shares his expertise as a member of the advisory committee(link is external) of the U.S. National Quantum Initiative(link is external). Monroe advocated for the creation of the initiative, which works to stimulate development of quantum information science and technology by fostering collaboration between federal organizations, academic institutions and private industry.

No more than 10% of OSA members may receive an OSA fellowship. The fellowship is an acknowledgment of accomplishments and contributions within the community of scientists who study light. Monroe was nominated for his “pioneering leadership in quantum information processing with trapped ions and ultrafast optics technology, and leadership in the National Quantum Initiative.”


Beverly Berger Receives APS Isaacson Award

Beverly K. Berger (Ph.D., ‘72) has been selected to receive the 2021 American Physical Society (APS) Richard A. Isaacson Award in Gravitational-Wave Science, which recognizes outstanding contributions in gravitational-wave physics, gravitational-wave astrophysics, and the technologies that enable this science. Berger was cited for supporting and expanding the community of scientists engaged in gravitational-wave research, and for fostering an international network of researchers devoted to theory and experimentation."

The award, which honors alumnus Richard Isaacson (Ph.D., ‘67), was established with funds donated by Nobel laureates Kip S. Thorne and Rainer Weiss to commemorate Isaacson’s impact on the study of gravitational waves. Isaacson’s research contributed to the theory of gravitational wave generation and propagation, and he later oversaw the development of the Laser Interferometer Gravitational-wave Observatory (LIGO) during his career as Program Director of Gravitational Physics at the National Science Foundation (NSF).

Berger did her thesis work on cosmological graviton creation under Professor Emeritus Charles Misner. Her career included 24 years in the Physics Department at Oakland University (MI), where she served a term as department chair, and 10 years as Program Director for Gravitational Physics at the NSF. She is a Fellow of the American Association for the Advancement of Science and of the APS.

Within the APS, Berger worked to establish the Topical Group on Gravitation, which eventually became the Division of Gravitational Physics (DGRAV). She has twice served as DGRAV chair, and also led the APS Committee on the Status of Women in Physics in 2000.

She joined the LIGO Scientific Collaboration (LSC) in 2012 and is now part of the Stanford University LIGO Group.

The CMNS story, The Chirps Heard Round the World, describes the University of Maryland’s contributions to gravitational wave science. The short documentary film Mirrors That Hang on Glass Threads illuminates the scale and complexity of the LIGO detector, while LIGO Detection tells the story of the September 2015 event in the words of many LIGO scientists.

Other University of Maryland APS awardees in this cycle are Nick Poniatowski, who received the LeRoy Apker Award, and Steve Fetter, Dean of the Graduate School and Professor of Public Policy, who received the Leo Szilard Award.