Langevin simulation approach to a two-dimensional coupled flashing ratchet

We study the directed motion of a Brownian particle moving in a two-dimensional coupled flashing ratchet driven by Gaussian white noise. The temperature dependence of the current is evaluated numerically in terms of Langevin simulation and discussed by means of a heuristic analytical ad hoc approximation. The current can be enhanced or reversed due to the coupling effects between two degrees of freedom. Our results show that the noise is rectified even in the absence of a true activation energy barrier and the two-dimensional ratchet current does not vanish as the temperature approaches infinity. (C) 1998 Elsevier Science B.V.