Regensburg 1998 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 41: Hauptvortrag

DY 41.1: Hauptvortrag

Donnerstag, 26. März 1998, 09:30–10:15, H2

Universal relaxation of fronts propagating into unstable states and implications for moving boundary approximations — •W. van Saarloos — Instituut-Lorentz, Leiden University, P.O. Box 9506, 2300 RA Leiden, Netherlands

It frequently occurs in physics that during the late stage dynamics, the evolution of some inhomogeneous nonequilibrium pattern can most conveniently be described in terms of the motion of a sharp interface. A well-known example is the analysis of the late stage of coarsening dynamics. Such approximations are possible when the pattern consists of large domains where the order parameter varies slowly, separated by thin interfacial zones where it varies rapidly. In this talk, we will argue that the validity of such a moving boundary approximation is intimately connected with the relaxation properties of the front that separates the two domains. In particular, we will show that a large class of fronts propagating into an unstable state exhibit a universal power law relaxation which is so slow that the standard moving boundary approximation breaks down. The universal power law relaxation of such so-called “pulled” or “linear marginal stability” fronts shows various similarities with universal corrections to scaling near a critical point.