Department of Physics at the U of I

Three Physics Illinois faculty members are among the 22 at Illinois to be awarded access to the Blue Waters supercomputer. Professor Oleksii Aksimentiev will study the molecular mechanism of DNA exchange; Professor Aida El-Khadra will look at semileptonic kaon decay form factors at the physical point; and Professor Stuart Shapiro will investigate gravitational and electromagnetic signatures of compact binary mergers through general relativistic simulations at the petascale. The Blue Waters supercomputer is capable of performing quadrillions of calculations every second and of working with quadrillions of bytes of data.

Wayne Higgins, Ph.D., who has spent much of his career at the forefront of weather and climate prediction for NOAA’s National Weather Service, starts his new position as director of NOAA’s Climate Program Office on July 28. Higgins earned his doctoral and master's degrees in meteorology from the Pennsylvania State University and his bachelor of science degree in physics from the University of Illinois at Urbana-Champaign.

Scientists have long sought to understand how the HIV capsid is constructed, and many studies have chipped away at its mystery. Researchers have used a variety of laboratory techniques—cryo-electron microscopy, cryo-EM tomography, nuclear magnetic resonance spectroscopy and X-ray crystallography, to name a few—to peer at individual parts of the capsid in revealing detail, or to get a sense of the whole. Until the arrival of petascale supercomputers, however, no one could piece together the entire HIV capsid—an assemblage of more than 1,300 identical proteins forming a cone-shaped structure—in atomic-level detail. The simulations that added the missing pieces to the puzzle were conducted during testing of Blue Waters, a new supercomputer at the National Center for Supercomputing Applications at the University of Illinois. “This is a big structure, one of the biggest structures ever solved,” said Professor Klaus Schulten, who, with postdoctoral researcher Juan R. Perilla, conducted the molecular simulations that integrated data from laboratory experiments performed by colleagues at the University of Pittsburgh and Vanderbilt University. “It was very clear that it would require a huge amount of simulation—the largest simulation ever published—involving 64 million atoms.”

Professor Charlie Slichter, long-time friend and colleague, said, “Bill Edelstein has contributed brilliant ideas to the design of the modern medical MRI machine, starting when MRI technology was first being developed and continuing through the period of its widespread application as a diagnostic tool. Today he is still working to refine and improve this important, sometimes lifesaving piece of equipment. Bill is part of a great legacy in MRI out of Physics Illinois: Paul Lauterbur and Sir Peter Mansfield, who shared the Nobel Prize for inventing MRI, worked here as professor and post doc respectively. And Walter Robb, who received this alumni achievement award in 2001, headed the team at GE that developed their commercial product.”

Physics Professors Yann Chemla, Taekjip Ha, and Paul Selvin presented their latest research to more than one hundred researchers from the US, Europe, and Japan, at the biennial Winter Aspen Physics Conference on Single Molecule Biophysics. Ha had the honor of giving this year’s public lecture at the Wheeler Opera House in Aspen; an annual tradition, it is attended by Aspenites as well as biophysicists. The lecture, entitled "Probing Nature's Nano-Machines with Light," was recorded and can be viewed online at the grassroots TV Aspen.

It sounds implausible, but two poor electrical conductors can be the building blocks for an excellent one. In 2004, experimentalists observed that thin films of LaAlO₃ and SrTiO₃, both wide-band-gap insulators, formed a metal at their interface. Later experiments showed this two-dimensional metal could support unusual transport properties, including superconductivity. Nadya Mason and colleagues systematically studied this interface and discovered that even small changes in the amount of lanthanum (la) in the LaAlO₃  layer can have large effects on the interfacial electrical resistance. As reported in Physical Review Letters, whether there is an excess or deficiency of La depends on how the samples are fabricated, but the difference can be easily missed by conventional sample characterization.

Recent Physics Illinois graduate Stephanie Brandt (BS 2012) and graduate student Courtney Byard were each selected for a three-year NSF Graduate Research Fellowship.

Professor of Physics Eduardo Fradkin has been elected to the National Academy of Sciences of the United States for his seminal contributions to theoretical physics. Joining Fradkin in the 2013 class is Professor of Chemistry and of Physics Martin Gruebele and Professor of Chemistry Sharon Hammes-Schiffer.