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Physicist Thouless to give two talks at Lab

One of the world's leading theoretical physicists will present a pair of talks at the Center for Non-Linear Studies (T-CNLS) on Tuesday and Wednesday.

Professor David Thouless of the University of Washington will be continuing his series of Mark Kac Memorial Lectures in the CNLS Conference Room, Building 1690 at Technical Area 3.

Thouless will discuss "Quantized vortices in superfluids and superconductors" at 10 a.m., on Tuesday, and "Dynamics in presence of noise: How special is the Boltzmann distribution?" at 10 a.m., on Wednesday.

Thouless' talk on Tuesday will include theoretical reasons and experimental evidence for discrete values (quantized) of circulation around non-superfluid defects in neutral superfluids and in superconductors, including vortices in clusters of trapped atoms. He will discuss some uncertainties and ambiguities in the theory of superfluids that have led to recent questions about how a non-superfluid defect moves, among others.

His talk on Wednesday on dynamics in the presence of noise will provide far-reaching implications for complex systems in general. Many complex systems are plausibly described by a Langevin equation that has two parts: one for motion that can be determined based on initial conditions, and the other a random forcing part that represents noise. Such an equation is descriptive of systems close to thermal equilibrium where the steady state is given by a thermal distribution for which there is no net interchange between any states of the system, Ecke said. Thouless will present an example of a system in which a thermal distribution is obtained without a restriction on net interchange between states of the system.

The Mark Kac Annual Memorial Lecture Series was established in 1985 as a continuing tribute to the founding chairman of the CNLS External Advisory Committee, for his lifelong commitment to the pursuit of scientific research of the highest quality and to the broad dissemination of the results of this research, Ecke said.

For more information, see the April 23 Daily Newsbulletin.

-- Jim Danneskiold