Hans R. Griem, 1928-2019

Prof. Emeritus Hans R. Griem, a noted expert in high-temperature plasmas and spectroscopy, died on October 2, 2019.

Prof. Griem received his Ph.D. from the Universität of Kiel, Germany, in 1954 and accepted a Fulbright Fellowship working on upper atmospheric physics at UMD. He returned to Universität Kiel for a two-year appointment before joining the UMD faculty in 1957.   He was well known for his research on radiation from highly ionized atoms in high temperature plasmas, and for his work on spectral line broadening (and shifts) in dense plasmas.  He was a consultant with Los Alamos National Laboratory during most of his career, and retired from UMD in 1994.

He was a fellow of the American Physical Society and a referee for several journals, including Physical Review Letters.  Among his accolades were a Guggenheim Fellowship, a Humboldt Award and the William F. Meggers Award of the Optical Society.  In 1991 he received the James Clerk Maxwell Prize in Plasma Physics for "his numerous contributions to experimental plasma physics and spectroscopy, particularly in the area of improved diagnostic methods for high temperature plasmas, and for his books on plasma spectroscopy and spectral line broadening in plasmas that have become standard references in the field."

Prof. Griem was instrumental in founding the UMD Institute Research in Electronics and Applied Physics, and served as one of the first directors of IREAP. He advised over 40 doctoral students in his time at UMD.

Jim Griffin, Hans Griem and Doug Currie in 2001.

In The Washington Post obituary published Oct. 6, 2019, the Griem family kindly directed donations in Prof. Griem's name to UMD Physics.


Workshop Explores Novel Ideas for Dark Matter Searches

The University of Maryland will host a two-day meeting to evaluate new methods for detecting dark matter—the as-yet-unseen substance that makes up the bulk of the matter in the universe. The meeting will be held on campus Oct. 28-29, 2019.

“The search for dark matter is entering a new phase,” says Dan Carney, a co-organizer of the event and a postdoctoral researcher at the Joint Quantum Institute. “Our first guesses for where to look have not worked out, and we need new ideas.”

Named for its apparent reluctance to interact with ordinary matter, dark matter has eluded decades of targeted searches. Astrophysical evidence for it abounds, from the rotation rates of distant galaxies to the large-scale structure of the universe, but terrestrial experiments have so far come up empty.

Part of the problem is that the weak interactions that give dark matter its name also make it hard to detect, since detectors are made of ordinary matter. If dark matter is (as many suspect) made of particles that don’t react much to protons and electrons, then it’s hard to imagine how it could ever be detected.

Parallel to this hunt for dark matter, scientists have been steadily improving the accuracy of quantum sensors, which utilize some of the quirky features of quantum physics to make incredibly accurate measurements of position and time. With sensitivities now down to a billionth of a billionth of a meter, researchers have started to wonder if they might wield quantum sensors in the hunt for dark matter. After all, dark matter is still matter, and it might be detected by looking for minute changes in gravity, which could potentially open up a whole new front in the search.

Carney, together with several collaborators, co-organized an event to bring together experts from the particle physics and quantum sensing communities—two groups that don’t often collaborate—to discuss novel ways of building the next generation of dark matter detectors. Carney says the meeting, which is titled “Quantum Optomechanical Architectures for Dark Matter Detection,” will feature ample time for discussion, and he hopes that it will lead to a roadmap that charts a course toward new experiments.

“Quantum sensing techniques are our best methods for detecting faint signals, and dark matter is as faint as they come,” Carney says. “We're excited to get a group of experts together to explore ways to leverage this technology to help figure out what dark matter is really made of.”

Carney’s co-organizers are Cindy Regal, a quantum sensing experimentalist from JILA; Gordan Krnjaic, a particle physics theorist from Fermilab; and Dave More, a particle physics experimentalist and quantum sensing expert from Yale. The meeting is supported by the American Physical Society through the Gordon and Betty Moore Foundation Fundamental Physics Innovation Awards.

Story by Chris Cesare This email address is being protected from spambots. You need JavaScript enabled to view it.

Joel Dahlin Receives Ronald Davidson Award

Joel DahlinJoel Dahlin

Alumnus Joel Dahlin, who earned his Ph.D. in 2015, has received the 2019 Ronald C. Davidson Award for Plasma Physics from AIP Publishing. Dahlin, who was advised by Distinguished University Professor James Drake and Marc Swisdak of the Institute for Research in Electronics and Applied Physics­­, is now a postdoctoral fellow at the NASA Goddard Space Flight Center.

AIP Publishing sponsors the award in collaboration with the American Physical Society’s Division of Plasma Physics (APS-DPP), to recognize one researcher each year whose outstanding work has been published in the journal Physics of Plasmas.

"AIP Publishing and Physics of Plasmas are delighted to award Joel T. Dahlin the 2019 Ronald C. Davidson Award for Plasmas Physics," said Jason Wilde, chief publishing officer at AIP Publishing. "Now in its fourth year, this award is in honor of the late Ron Davidson, the long-time Editor-in-Chief of Physics of Plasmas."

Dahlin is being honored for his article, "The mechanisms of electron heating and acceleration during magnetic reconnection," written with Drake and Swisdak. It was selected from the most highly cited and most highly downloaded articles published in Physics of Plasmas during the past five years. 

“It is a great honor to be recognized with an award bearing Ron Davidson’s name, given his broad and influential contributions to the field of plasma physics. Since my co-authors and I published our work, it has been exciting and deeply gratifying to see how other researchers have used and built on the ideas we laid out,” Dahlin said.

The paper explored the mechanisms for electron acceleration caused by collision-less magnetic reconnection in plasma with a magnetic guide field sufficient for adiabatic electron motion. In a follow-up paper, “Electron acceleration in three-dimensional magnetic reconnection with a guide field,” Physics of Plasmas 22, 100704 (2015), Dahlin and his co-authors showed a dramatic enhancement of energetic electron production in 3D systems where stochastic magnetic fields enable continuous access to volume-filling acceleration regions.

According to Spiro K. Antiochos of NASA GSFC, "Joel Dahlin's results on particle acceleration during magnetic reconnection, especially on the effects of a guide field, may well be the key to finally understanding two decades-old major puzzles in the plasma physics of solar flares: How are flares so efficient at accelerating electrons, and why does the acceleration occur only during the early, impulsive phase of a flare?”

Dahlin will be presented with the award during the 61st Annual Meeting of the APS Division of Plasma Physics on Tues., Oct. 22.

For more information, please see the AIP announcement here.

Quantum Materials Symposium to Showcase Local Expertise and Highlight Partnerships in D.C. Region

The University of Maryland held a one-day symposium focusing on local research into quantum materials—condensed matter systems that exhibit strong quantum effects and hold promise as potential components in next-generation computers, sensors and other devices on Sept. 26, 2019, in the Kim Engineering Building.  

Hosted by UMD’s Center for Nanophysics and Advanced Materials (CNAM)—which will be renamed the Quantum Materials Center next month—the event broght together researchers from the university’s Departments of Physics, Chemistry and Biochemistry, Electrical and Computer Engineering, and Materials Science and Engineering, in addition to researchers from the nearby National Institute of Standards and Technology (NIST) and the Laboratory for Physical Sciences. Around 50 quantum materials researchers and institutional leaders were expected to attend.

CNAM Director and Professor of Physics Johnpierre Paglione, together with Joint Quantum Institute (JQI) Fellow and Assistant Professor of Physics James Williams, organized the event, which included talks on recent quantum materials research as well as reflections on collaborations that have formed among UMD researchers and also between researchers at UMD and area partners such as NIST.

“Fundamental studies of quantum materials play a critical role in not only supporting current development of quantum technologies, but also the discovery of new phenomena that hold promise for future applications,” Paglione said. “This symposium will bring together the top experts from our local community and will hopefully sprout new collaborations and partnerships.”

Amitabh Varshney, dean of UMD’s College of Computer, Mathematical, and Natural Sciences, and Robert Briber, associate dean of UMD’s A. James Clark School of Engineering, delivered their perspectives on campus initiatives in quantum science, including the newly formed Quantum Technology Center. Carl Williams, a JQI Fellow and the acting director of the Physical Measurement Laboratory at NIST, discussed aspects of the National Quantum Initiative, and Dan Neumann, group leader of neutron condensed matter science at the NIST Center for Neutron Research (NCNR), discussed the partnership between CNAM and NCNR, which recently led to the discovery of a superconductor that may be useful in future quantum computers.

“CNAM maintains strong interdisciplinary collaborations with researchers across several departments and institutes,” Paglione said. “Going forward, we want to strengthen those partnerships, which have contributed to the success of CNAM’s fundamental research on quantum materials.”

Jeffrey Lynn, a NIST Fellow and adjunct professor of physics at UMD, is the team leader for condensed matter physics at NCNR. He noted, “There have been longstanding multidisciplinary cooperative research collaborations between NIST and UMD in general, and the NCNR and CNAM in particular,” Lynn says. “In addition to the research output, these collaborations provide cross-institutional research capabilities for students, postdoctoral fellows, and scientific staff that are essential to perform the best quantum materials research.”

 QMC logoQMC @ UMD

Story by Chris Cesare, This email address is being protected from spambots. You need JavaScript enabled to view it.

Nobel Laureate Donna Strickland Delivers Paint Branch Lecture

2018 Nobel Laureate Donna Strickland of the University of Waterloo, the third woman to win the Nobel Prize in Physics (after Marie Curie in 1903 and Maria Goeppert Mayer in 1963) visited UMD on September 19 to deliver the 2019 Paint Branch Distinguished Lecture in Applied Physics.  In addition to giving her talk, “From Nonlinear Optics to High-Intensity Laser Physics”, Strickland met with an enthusiastic group of women graduate students.

Donna Strickland visited UMD on 9/19/19.Donna Strickland visited UMD on 9/19/19.

Strickland earned her Ph.D. at the University of Rochester, and held appointments at the National Research Council Canada, Lawrence Livermore National Laboratory, and Princeton University before joining the University of Waterloo in 1997.  She has received a Sloan Research Fellowship, a Premier’s Research Excellence Award and a Cottrell Scholar Award. She is a past president of the Optical Society (OSA) and is an OSA Fellow and an SPIE Fellow.