Paradoxical directed diffusion due to temperature anisotropies

Universität Bielefeld, Fakultät für Physik Universitätsstraße 25, 33615 Bielefeld, Germany

Received: 29 October 2004
Accepted: 14 December 2004

Abstract

An analytically tractable, but still experimentally realistic model dynamics is investigated, describing the Brownian motion of a particle in a “meandering” periodic potential landscape under the simultaneous influence of two different heat baths. The main characteristics of the resulting far-from-equilibrium environment is an anisotropy of the ambient temperature. When an external static force F is applied, the particle moves in the direction opposite to that force (absolute negative mobility), and this even for arbitrarily large forces . Moreover, even when the “meandering” potential exhibits a broken spatial symmetry, no preferential direction of motion arises for .