Efficiency of energy transformation in an underdamped diffusion ratchet

The transport of an underdamped Brownian particle moving in a one-dimension al ratchet driven by a modulated Gaussian white noise is considered. The sy stem experiences periodically higher temperature T-1 during a time tau(1) a nd lower temperature T-2 during a time tau(2). Both the average current and the thermal efficiency are calculated numerically. The results show that t he efficiency of energy transformation can be optimized for a ratio of tau( 1)/tau(2) less than 1 at a critical damping. (C) 2000 Published by Elsevier Science B.V. Ail rights reserved.