  The present work studies a non-Markovian forced thermal ratchet model on an
asymmetric periodic potential. The Brownian dynamics is described by a
generalized Langevin equation with an Ornstein-Uhlenbeck-type friction memory
kernel. We show that for the case of a time-dependent driving force, also in
the form of an Ornstein-Uhlenbeck-like process, an exact expression of the
probability current can be derived. We also obtain the behavior of the
particle's average rate of flow as a function of the external amplitude force
and of the bath temperature when the driving force behaves as a square wave
modulation. All our results are compared with those obtained in the Markovian
case and we find, fairly remarkably, that in some cases a friction memory
kernel results in an enhancement of the current
