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Monday, August 16, 2004
3:00 PM - 4:00 PM
CNLS Conference Room (TA-3, Bldg 1690)

Seminar

Dynamics of model colloidal suspensions and the colloidal glass transition: Brownian Dynamics simulations, mode-coupling theory and all that

Grzegorz Szamel
Colorado State University

Due to the abundance of experimental data the colloidal glass transition has emerged in recent years as a favorite, model glass transition to be studied. I will start this colloquium with an introduction to model colloidal systems. Next, I will briefly review the most popular theory used to describe the colloidal glass transition, i.e. the mode-coupling theory. In the second part of the talk I will focus on two recent results. The first one is concerned with the independence of the glass transition of the microscopic dynamics. I will show that near the so-called mode-coupling transition temperature, dynamic properties of the Brownian system exhibit the same deviations from mode-coupling-like power-law behavior as those of the Newtonian system. Thus, similar dynamical events cut off the idealized mode-coupling transition in Brownian and Newtonian systems. I will discuss implications of this result for extended mode-coupling theory. Next, I will present a new theory for the colloidal glass transition. This theory goes beyond the standard mode-coupling approximation: it uses a factorization approximation at the level of a higher order memory function. The theory predicts an ergodicity breaking transition similar to that predicted by the mode-coupling theory, but at a higher density.