Correlation ratchets: four current reversals and disjunct "windows"

Multinoise correlation ratchets with a simple sawtooth potential are considered. It is proved that in the case of symmetric nonequilibrium three-level Markovian noise the direction and value of the induced current can be controlled by thermal noise. Moreover, it is established that four current reversals (CRs) occur and that for the CRs there exist characteristic disjunct "windows" in temperature and switching rate as control parameters. The necessary and sufficient conditions for the existence of the above effects are given and can be used in particle separation techniques.