Dresden 2011 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 41: Brownian Motion, Stochastic Processes, Transport II
DY 41.6: Vortrag
Freitag, 18. März 2011, 11:30–11:45, HÜL 186
Random walks in active media: perturbation spreading in many-body systems — Vasily Zaburdaev1, •Sergey Denisov2, and Peter Hanggi2 — 1School of Engineering and Applied Science, Harvard University, 29 Oxford Str., Cambridge, MA 02138 USA — 2Institut fur Physik, Universitat Augsburg, Univeritatsstr. 1, 86135 Augsburg
Propagation of an initially localized perturbation through a many-particle Hamiltonian system can be viewed as a diffusion process,due to the conservation of perturbation energy. Remarkably, conventional diffusion equations are not suitable for the description of this process. We argue that the perturbation spreading can be evaluated by use of a Levy walk formalism, and develop a model that describes the dynamics of a cloud of walkers spreading through an active medium. By using two renowned many-particle systems, that is (i) a hard-point gas and (ii) a Fermi-Pasta-Ulam chain, we demonstrate that the perturbation profiles of both systems coincide with the diffusion profiles of the generalized Levy walk process. Parameters of the model are related to the physical parameters of the corresponding testing systems by simple algebraic expressions. Finally we discuss possible practical applications of our findings.