Three and four current reversals versus temperature in correlation   ratchets with a simple sawtooh potential
  Transport of Brownian particles on a simple sawtooth potential subjected to both unbiased thermal and nonequilibrium symmetric three-level Markovian noise is considered. The new 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 novel current reversals are found. 
Risto Tammelo, Romi Mankin, Dmitri Martila