Brownian motors: current fluctuations and rectification efficiency
Abstract
With this work we investigate an often neglected aspect of Brownian motor transport: The r\^{o}le of fluctuations of the noise-induced current and its consequences for the efficiency of rectifying noise. In doing so, we consider a Brownian inertial motor that is driven by an unbiased monochromatic, time-periodic force and thermal noise. Typically, we find that the asymptotic, time- and noise-averaged transport velocities are small, possessing rather broad velocity fluctuations. This implies a corresponding poor performance for the rectification power. However, for tailored profiles of the ratchet potential and appropriate drive parameters, we can identify a drastic enhancement of the rectification efficiency. This regime is marked by persistent, uni-directional motion of the Brownian motor with few back-turns, only. The corresponding asymmetric velocity distribution is then rather narrow, with a support that predominantly favors only one sign for the velocity.
Keywords
Cite
@article{arxiv.cond-mat/0409314,
title = {Brownian motors: current fluctuations and rectification efficiency},
author = {L. Machura and M. Kostur and P. Talkner and J. Luczka and F. Marchesoni and P. Hanggi},
journal= {arXiv preprint arXiv:cond-mat/0409314},
year = {2007}
}
Comments
9 pages, 4 figures