Brownian motors: current fluctuations and rectification efficiency.

L Machura; M Kostur; P Talkner; J Łuczka; F Marchesoni; P Hänggi

doi:10.1103/physreve.70.061105

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Brownian motors: current fluctuations and rectification efficiency.

L Machura·M Kostur·P Talkner·J Łuczka·F Marchesoni·P Hänggi

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Abstract

With this work, we investigate an often neglected aspect of Brownian motor transport, namely, the role 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, unidirectional 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.

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L Machura, M Kostur, P Talkner, J Łuczka, F Marchesoni, P Hänggi. 2004-12-20. Brownian motors: current fluctuations and rectification efficiency.. https://doi.org/10.1103/physreve.70.061105

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