UMD Physics Efforts Cited Among 2012's Most Important

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Category: Department News

Published: Monday, December 24 2012 00:00

Physics World's compilation of the year's biggest discoveries included the work of several UMD physicists. The highest-rated discovery was that of the Higgs particle reported by the ATLAS and CMS collaborations at CERN. Professors Drew Baden, Sarah Eno, Nick Hadley and Andris Skuja are all collaborators on CMS, and have made significant contributions in the building, running, and analysis of the data. Professor Alberto Belloni will join the department from ATLAS in January, and will become the fifth faculty member on CMS, an international collaboration.

One of the next highest-rated discoveries was attributed to Leo Kouwenhoven and colleagues at Delft University for confirmation of the Majorana fermion, closely following a prediction by Sankar Das Sarma and UMD/JQI colleagues in 2010.

The BaBar experiment's discovery of time-reversal invariance in the quark sector also made the top-10 list. Professors Hassan Jawahery and Doug Roberts played key roles on BaBar, another large international experiment using electron-positron beams at SLAC. Jawahery served as the physics analysis coordinator and later as spokesperson (overall leader) of the experiment.

The Dec. 21 edition of Science named the Higgs boson as the year's top discovery and also cited the importance of the Majorana fermion. 

JQI and CNAM Researchers Uncover New Exotic Insulator

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Category: Research News

Published: Friday, December 14 2012 00:00

Topological insulators have recently emerged as a new and exciting form of quantum matter, in which topologies of the system (rather than symmetries) dictate the physical properties much like the situation found for the quantum Hall effect. To date, the majority of research has focused on non-interacting electron materials such as the bismuth-dichalcogenides, where the nearly free-electron model is sufficient to explain the non-trivial electronic structures that give rise to the observed topological states. An extension of this approach to strongly-correlated electron systems is challenging owing to the difficulty in determining the correct band structure by calculation, and remains as the next grand challenge in condensed matter physics.

A pioneering advance in this direction was made in 2009 by the team of Victor Galitski, who showed that a particularly simple type of heavy-electron material called a Kondo insulator, in which a filled band of heavy quasiparticles gives rise to a narrow band insulator, can host a three-dimensional topological insulating phase analogous to the non-interacting systems such as Bi2Se3. They developed a topological classification scheme for the emergent band structures of these systems, and predicted that at least one compound, samarium hexaboride, may be an ideal candidate.

Recently, this work and experiments performed in the Center for Nanophysics and Advanced Materials by the teams of Johnpierre Paglione and Richard Greene were highlighted in Nature [vol. 492, 165 (2012)] and Scientific American [December 12, 2012]. The experiments, using a technique called point-contact spectroscopy, explored the nature of the Kondo insulator SmB6 and found that the material indeed hosts an unusual metallic surface state as predicted by Dzero and co-workers, even though the bulk of the material becomes insulating upon cooling. Confirmed by other groups studying the properties of the surface state transport, this observation paves the way for the discovery of a new class of strongly-correlated topological insulator materials.

December 14, 2012

Jon McKinney Publishes in Science Express

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Category: Department News

Published: Thursday, December 13 2012 00:00

Assistant Professor Jon McKinney's article, Alignment of Magnetized Accretion Disks and Relativistic Jets with Spinning Black Holes (with Alexander Tchekhovskoy and Roger D. Blandford) was published in Science Express. 

November 15, 2012

Four UMD Physicists Named AAAS Fellows

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Category: Department News

Published: Thursday, November 29 2012 00:00

Four UMD physicists have been named Fellows of the American Association for the Advancement of Science (AAAS). Election as a Fellow is an honor bestowed upon AAAS members by their peers. 

Drew Baden - For distinguished contributions to the field of experimental particle physics, particularly for ideas contributing to the discovery of the top quark and to searches for new particles.

Michael Fuhrer - For experimental studies of the fundamental electronic transport properties of nanostructured carbon materials.

Ted Jacobson - For contributions to quantum gravity, black hole thermodynamics, and the formulation and phenomenology of Lorentz-violating modifications of particle and gravitational physics.

Chris Monroe - For the development and demonstration of novel techniques for quantum information processing and quantum simulation with trapped ions.

Other UMD Fellows named were Millard Alexander, Marco Columbini, William Fagan, Cynthia Moss, Aravind Srinivasan and Raymond St. Leger. New Fellows will be presented with an official certificate and a gold and blue (representing science and engineering, respectively) rosette pin on Saturday, 16 February, at the AAAS Fellows Forum during the 2013 AAAS Annual Meeting in Boston, Mass.

November 29, 2012