CHAMPAIGN, IL — Anthony J. Leggett, a world leader in the theory of low-temperature physics and a faculty member at the University of Illinois at Urbana-Champaign, has been awarded the 2003 Nobel Prize in physics. He shares the prize with Alexei A. Abrikosov of Argonne National Laboratory in Argonne, Ill., and Vitaly L. Ginzburg of the Lebedev Physical Institute in Moscow. They were lauded for "pioneering contributions to the theory of superconductors and superfluids," the Royal Swedish Academy of Sciences that awards the prize said in its news release from Stockholm. "Superconducting material is used, for example, in magnetic resonance imaging for medical examinations and particle accelerators in physics. Knowledge about superfluid liquids can give us deeper insight into the ways in which matter behaves in its lowest and most ordered state." "Tony Leggett approaches his work in physics as a philosopher as well as a physicist," said Nancy Cantor, the chancellor of the Urbana campus. "His work helps us understand the ways that matter behaves in its most ordered state. His discovery, that superfluids exhibit the same properties observed in quantum mechanics, can be used to help test whether the laws of quantum physics hold on a large scale." In a superconductor, electrons are attracted to one another and form pairs, resulting in an electrical current that flows with no resistance. The BCS theory—developed in 1957 by John Bardeen, Leon Cooper and John Schrieffer (all three researchers were at the University of Illinois at that time, and shared the Nobel Prize in Physics in 1972)—explains superconductivity at temperatures close to absolute zero, but has difficulty accounting for the higher temperatures that were later achieved with copper-containing superconductors. Just as superconductors have no electrical resistance, superfluids have no viscosity, and can flow freely. Leggett, 65, who holds the John D. and Catherine T. MacArthur Chair of Physics and is a professor in the Center for Advanced Study at Illinois, shaped the theoretical understanding of normal and superfluid helium liquids and other strongly coupled superfluids. In the 1970s, he formulated a decisive theory explaining how atoms interact and are ordered in the superfluid state of the rare isotope He-3. "It is considered likely that Leggett will someday receive a Nobel Prize for his theory of superfluid He-3, if not for some future discovery," two-time Nobel laureate Bardeen once wrote. Leggett's groundbreaking theoretical work has helped provide a better understanding of both high-temperature superconductivity and low-temperature superfluidity. He was cited in the announcement of the 1996 Nobel Prize in physics for assisting the prize winners in their interpretation of the experiments that led to a breakthrough in low-temperature physics. His areas of research also have included foundations of quantum mechanics and the thermal and acoustic properties of glass. Nine Nobel laureates have served on the UI faculty. A native of London, Leggett earned his doctorate in physics from Oxford University in 1964. He worked at Illinois as a postdoctoral research associate from 1964-5 and again in 1967. He returned to Illinois and joined the faculty in 1983. Leggett has achieved many honors, including being named a fellow of the Royal Society, the American Physical Society, and the American Institute of Physics. He is an honorary fellow of the British Institute of Physics. He also is a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Philosophical Society. Leggett has been awarded the Wolf Prize in physics from the Wolf Foundation, the Maxwell Medal and Prize and the Simon Memorial Prize of the British Institute of Physics, and he is a foreign member of the Russian Academy of Sciences.