Speaker:Maria Cameron, American University
Title: Computing Transition Paths in Stochastic Systems

Abstract: Many processes in nature are modeled using stochastic differential equations. Examples include thermally-activated small-scale processes in physics and chemistry such as conformational changes in molecules, chemical reactions, magnetization switches and nucleation events. Other examples come from such fields as evolutionary biology and stochastically modeled computer networks. I will consider two stochastic systems: a system without detailed balance evolving according to a nongradient stochastic differential, and a stochastic network associated with the Lennard-Jones-38 cluster. In both cases the noise is small so that the direct simulation is inefficent. In the first system, I will introduce a method for computing the quasipotential, a function that determines the transition rates and transition paths in the case of small noise. I will present the results of analysis of the second system using three different approches: the discrete transition path theory approach, the zero-temperature approach, and a heuristic approach.

Time: Friday, September 21, 2012, 1:30-2:30 p.m.

Place: Planetary Hall (formerly Science and Tech I), Room 242

Department of Mathematical Sciences
George Mason University
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Fairfax, VA 22030-4444
http://math.gmu.edu/
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