Ratchet driven by quasimonochromatic noise

The currents generated by noise-induced activation processes in a periodic potential are investigated analytically, by digital simulation and by perfo rming analog experiments. The noise is taken to be quasimonochromatic and t he potential to be a smoothed sawtooth. Two analytic approaches are studied . The first involves a perturbative expansion in inverse powers of the freq uency characterizing quasimonochromatic noise and the second is a direct nu merical integration of the deterministic differential equations obtained in the limit of weak noise. These results, together with the digital and anal og experiments, show that the system does indeed give rise, in general, to a net transport of particles. All techniques also show that a current rever sal exists for a particular value of the noise parameters.