Berlin 2008 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
DY: Fachverband Dynamik und Statistische Physik
DY 14: Statistical physics II (general)
DY 14.1: Invited Talk
Tuesday, February 26, 2008, 14:00–14:30, MA 004
When it helps to be purely Hamiltonian: Acceleration of rare events, enhanced particle and energy transport — •Dirk Hennig1, Lutz Schimansky-Geier1, and Peter Hänggi2 — 1Institut für Physik, Humboldt Universität zu Berlin, Newtonstr. 15, 12489 Berlin — 2Insitut für Physik, Universität Augsburg, Universitätsstr. 1, 86135 Augsburg
In the first part we present a deterministic escape of chains of interacting units from a metastable state over an anharmonic potential barrier. The underlying dynamics is conservative and noise-free. The mutual interplay between nonlinearity and interaction causes that an initially uniform lattice state becomes unstable, leading to energy redistribution with strong localization. As a result a spontaneously emerging localized mode grows into a critical nucleus. By surpassing this transition state, the nonlinear chain manages a self-organized, deterministic barrier crossing. Most strikingly, these noise-free, collective nonlinear escape events proceed generally by far faster than the transitions assisted by thermal noise when the ratio between the average energy supplied per unit in the chain and the potential barrier energy assumes small values.
In the second part we discuss the formation of directed transport in driven Hamiltonian systems. Most crucially,the overall system dynamics is unbiased in the sense that the force averaged over time and space vanishes. Nevertheless we demonstrate that for adiabatic time-periodic modulations of the tilt of a symmetric and spatially periodic potential a giant transient directed current is induced.