APPROACH TO STEADY-STATE CURRENT IN RATCHETS

We have studied the approach to the steady state in thermal ratchets l ooking for signs of the future development of a non-zero current. We h ave concentrated on the evolution of the statistical root mean square fluctuations of the position of the walker as well as its temporal cor relations. We find oscillations and abrupt slope variations in the flu ctuations in the position of the ratchet particle and the temporal cor relation functions. These effects are due to the fact that the flippin g time of the potential is the same order of magnitude as the adiabati c adjustment time for the barrier. We find no oscillations when the fl ipping time is too low or too high compared with the adiabatic adjustm ent time.