Mechanism of hypersensitive transport in tilted sharp ratchets.

The noise-flatness-induced hypersensitive transport of overdamped Brownian particles in a tilted ratchet system driven by multiplicative nonequilibrium three-level Markovian noise and additive white noise is considered. At low temperatures, the enhancement of current is very sensitive to the applied small static tilting force. It is established that the enhancement of mobility depends nonmonotonically on the parameters (flatness, correlation time) of multiplicative noise.

Three and four current reversals versus temperature in correlation ratchets with a simple sawtooth potential.

Transport of Brownian particles in a simple sawtooth potential subjected to both unbiased thermal and nonequilibrium symmetric three-level Markovian noise is considered. The effects of three and four current reversals as a function of temperature are established in such correlation ratchets. The parameter space coordinates of the fixed points associated with these current reversals and the necessary and sufficient conditions for the existence of the current reversals are found.