Giant enhancement of diffusion and particle selection in rocked periodic potentials
Institut für Physik, Universität Augsburg - D-86135 Augsburg, Germany
2 Chemical Physics Department, Weizmann Institute of Science - Rehovot 76100, Israel
Accepted: 1 October 1998
We investigate the motion of an overdamped Brownian particle in a periodic potential with weak thermal noise and a time-periodic unbiased (i.e. ) external driving force F(t). By introducing appropriate “waiting-periods”, where F(t) vanishes, an arbitrarily strong enhancement of diffusion in a symmetric potential is possible. In asymmetric periodic potentials (ratchets) the net flux of particles can be directed in both directions, even in the absence of thermal noise. For finite temperatures we observe and explain additional, pure-noise–induced flux reversal phenomena.
PACS: 05.40.+j – Fluctuation phenomena, random processes, and Brownian motion / 05.60.+w – Transport processes: theory / 66.10.Cb – Diffusion and thermal diffusion
© EDP Sciences, 1998