Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 31: Statistical Physics far from Equilibrium

DY 31.9: Hauptvortrag

Freitag, 26. März 2010, 12:30–13:00, H38

Noise controlled transport in constrained geometries — •Fabio Marchesoni — Dipartimento di Fisica, Universita' di Camerino, I-62032 Camerino, Italy

Diffusive transport of particles or, more generally, small objects, is a ubiquitous feature of physical and chemical reaction systems [1]. In configurations containing confining walls or constrictions, transport is controlled both by the fluctuation statistics of the jittering objects and the phase space available to their dynamics. Consequently, the study of transport at the macro- and nanoscales must address both Brownian motion and entropic effects [2].

We report on recent advances in the theoretical and numerical investigation of stochastic transport occurring either in microsized geometries of varying cross sections or in narrow channels wherein the diffusing particles are hindered from passing each other (single-file diffusion). For particles undergoing biased diffusion in static suspension media enclosed by confining geometries, transport exhibits intriguing features such as 1) a decrease in nonlinear mobility with increasing temperature and 2) a broad excess peak of the effective diffusion above the free diffusion limit [1]. If, in addition, the suspension medium is subjected to external, time-dependent forcing, rectification of the diffusing Brownian particles sets on, at times with anomalous negative mobility.

[1] P. Hänggi and F. Marchesoni, Rev. Mod. Phys. 81, 387 (2009)

[2] P. S. Burada, P Hänggi, F.Marchesoni, G.Schmid, P. Talkner, ChemPhysChem 10, 45 (2009)