Brownian motors: current fluctuations and rectification efficiency.
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.
Machura
L
L
Institute of Physics, University of Augsburg, Universitätsstrasse 1, D-86135 Augsburg, Germany.
Kostur
M
M
Talkner
P
P
Łuczka
J
J
Marchesoni
F
F
Hänggi
P
P
D003198:Computer Simulation; D004058:Diffusion; D004735:Energy Transfer; D044085:Microfluidics / Q000379:methods*; D008956:Models, Chemical; D015233:Models, Statistical; D020409:Molecular Motor Proteins / Q000737:chemistry*; D009038:Motion; D013269:Stochastic Processes; D013314:Stress, Mechanical
D020409:Molecular Motor Proteins