Experiments at the LHC are once again recording collisions at extraordinary energies

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Category: Research News

Published: Thursday, May 12 2016 14:24

After months of winter hibernation the world’s most powerful particle accelerator is once again smashing protons and taking data. The Large Hadron Collider will run around the clock for the next six months and produce roughly 2 quadrillion high-quality proton collisions, six times more than in 2015 and just shy of the total number of collisions recorded during the nearly three years of the collider’s first run.

Between 2010 and 2013 the LHC produced proton-proton collisions with 8 teraelectronvolts of energy. In the spring of 2015, after a two-year shutdown, LHC operators ramped up the collision energy to 13 TeV. This increase in energy enables scientists to explore a new realm of physics that was previously inaccessible. Run II collisions also produce Higgs bosons – the groundbreaking particle discovered in LHC Run I – 25 percent faster than Run I collisions and increase the chances of finding new massive particles by more than 40 percent.

During this run, University of Maryland physicists will continue looking for new particles, including those that make up dark matter. Although the nature of dark matter and its counterpart, dark energy, remain a complete mystery, taken together they make up a total of around 95 percent of the universe.

The signature that will indicate the dark matter particle is known as missing transverse energy. UMD physicists are very familiar with this measurement, as they are a leading institution in the missing transverse energy group of the LHC’s Compact Muon Solenoid (CMS) detector.

Members of the Maryland group will also study collisions of nuclei with the CMS detector as well as the details of the interactions of the particles responsible for the sun’s energy. UMD physicists will also harness the LHC to investigate the origin of matter-antimatter asymmetry in the universe. When the Big Bang created matter, it also created an equal quantity of antimatter, made up of particles with identical mass but an opposite electrical charge. For as-yet unknown reasons, antimatter is no longer common in the universe, but can be recreated in particle accelerators such as the LHC.

UMD’s Hassan Jawahery leads a group that will use the LHCb detector to study the “beauty” or “bottom” quark— hence the “b” in the detector’s name. The collider will also produce the antimatter counterpart to the beauty quark. Comparing the properties of these two complementary particles could reveal laws of nature that treat matter and antimatter differently.

Key members of the University of Maryland LHC Team are available to comment on their work:
Drew Baden, Chair and Professor
Alberto Belloni, Assistant Professor
Sarah Eno, Professor
Nicholas Hadley, Professor
Hassan Jawahery, Distinguished University Professor and Gus T. Zorn Professor
Alice Mignery, Professor
Andris Skuja, Professor

Novel gate may enhance power of Majorana-based quantum computers

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Category: Research News

Published: Thursday, May 12 2016 09:01

Quantum computers hold great potential, but they remain hard to build because their basic components—individual quantum systems like atoms, electrons or photons—are fragile. A relentless and noisy background constantly bombards the computer’s data.

One promising theoretical approach, known as topological quantum computing, uses groups of special particles confined to a plane to combat this environmental onslaught. The particles, which arise only in carefully crafted materials, are held apart from each other so that the information they store is spread out in space. In this way, information is hidden from its noisy environment, which tends to disrupt small regions at a time. Such a computer would perform calculations by moving the particles around one another in a plane, creating intricate braids with the paths they trace in space and time.

Although evidence for these particles has been found in experiments, the most useful variety found so far appear only at the ends of tiny wires and cannot easily be braided around one another. Perhaps worse for the prospect of quantum computing is that these particles don’t support the full power of a general quantum computer—even in theory.

Now, researchers at JQI and the Condensed Matter Theory Center (CMTC) at the University of Maryland, including JQI Fellows Sankar Das Sarma and Jay Deep Sau, have proposed a way to dispense with both of these problems. By adding an extra process beyond ordinary braiding, they discovered a way to give a certain breed of topological particles all the tools needed to run any quantum calculation, all while circumventing the need for actual braiding. The team described their proposal last month in Physical Review X.

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The Department of Physics announces promotions and appointments effective July 1, 2016

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Category: Department News

Published: Tuesday, May 10 2016 08:47

Ian Appelbaum, who was promoted to the rank of Professor, joined UMD Physics in 2008. His experimental and theoretical research focuses on semiconductor device physics including spin-polarized electron transport and relaxation mechanisms, electronic properties of two-dimensional semiconductors, and novel phenomena in topological materials. He received his Ph.D. in physics from the Massachusetts Institute of Technology, and won the 2011 Outstanding Young Scientist award of the Maryland Academy of Sciences.

Zackaria Chacko, who was promoted to the rank of Professor, is a theoretical physicist and a founding member of the Maryland Center for Fundamental Physics (MCFP). His research interests lie in elementary particle physics, the field that studies the fundamental constituents of matter and their interactions. The primary focus of Professor Chacko's research is the study of new theories that can explain some of the puzzles of the current Standard Model of particle physics, and that can be tested by current or upcoming experiments. He received his PhD at this University, where he received the Pelczar Award for Outstanding Graduate Study.

Chris Jarzynski, currently a Professor in the Department of Chemistry and Biochemistry and Director of IPST, will hold a joint appointment with Physics. He received his PhD in physics at the University of California, Berkeley, and works on nonequilibrium behavior and computational methods for estimating thermodynamic properties. He is a Distinguished University Professor, and was recently elected a Fellow of the American Academy of Arts and Sciences.

Lennard Fisk, ​a member of the National Academy of Sciences and former NASA Associate Administrator for Space Science and Applications, has been appointed a College Park Professor. He received the NASA Distinguished Service Medal in 1992 and its Exceptional Public Service Medal in 2008. He is the Thomas M. Donahue Distinguished University Professor of Space Science at the University of Michigan.

Distinguished University Professor Christopher Monroe Elected to National Academy of Sciences

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Category: Department News

Published: Tuesday, May 03 2016 15:06

University of Maryland Physics Professor Christopher Monroe has been elected to the National Academy of Sciences. 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.

Monroe is one of 84 new members and 21 foreign associates elected in 2016, joining a select group of 2,291 scientists around the country recognized for their influential research and elected by their peers. Monroe is a scientific leader in trapping atomic ions and using their quantum properties for novel information processing tasks.

After graduating from MIT, Monroe earned his Ph.D. in physics from the University of Colorado. From 1992 until 2000, he worked at the National Institute of Standards and Technology in Boulder, Colorado, where he helped demonstrate the first quantum logic gate and pioneered the use of atoms for quantum memory devices. From 2000 until he joined UMD in 2007, Monroe was a faculty member at the University of Michigan.

In 2008, Monroe’s group produced quantum entanglement between two widely separated atoms and for the first time teleported quantum information between matter separated by a large distance. Since 2009, his group has used ultrafast laser pulses for speedy quantum entanglement operations, pioneered the use of trapped ions for quantum simulations of many-body models related to quantum magnetism, and has proposed and taken the first steps toward creating a large-scale, reconfigurable and modular quantum computer. He recently co-authored a feature article in Scientific American on the promise of modular quantum computing systems.

Monroe is also a fellow of the American Physical Society, the Institute of Physics and the American Association for the Advancement of Science. He has received numerous awards and honors, including the Arthur Schawlow Prize in Laser Science from the American Physical Society, the I.I. Rabi Prize from the American Physical Society, a Presidential Early Career Award for Scientists and Engineers, the International Quantum Communication Award, and the CMNS Board of Visitors Distinguished Faculty Award.