Brownian rectifiers in the presence of temporally asymmetric unbiased   forces
  The efficiency of energy transduction in a temporally asymmetric rocked ratchet is studied. Time asymmetry favours current in one direction and suppresses it in the opposite direction due to which large efficiency ~ 50% is readily obtained. The spatial asymmetry in the potential together with system inhomogeneity may help in further enhancing the efficiency. Fine tuning of system parameters considered leads to multiple current reversals even in the adiabatic regime. 
Raishma Krishnan, Mangal C. Mahato, A. M. Jayannavar