Inertia ratchets:: A numerical study versus theory

The colored (Ornstein-Uhlenbeck) noise-driven nonequilibrium dynamics of massive damped Brownian particles in a periodic but asymmetric potential (ratchet) is investigated. Our special focus is on the influence of inertia in the particle dynamics for the noise induced, directed current. By means of two approximation schemes (a unified colored noise approximation and a path-integral approach) and by numerical matrix-continued-fraction evaluations of the inherent, three-dimensional Fokker-Planck dynamics as well as by direct simulations of the stochastic differential equations we examine the dynamics at various inertial strengths. For the case of a large mass we find current reversal with respect to both a variation of the mass and of the noise-correlation time. Possibilities for efficient mass-sensitive scenarios for separation of particles are discussed.