  We perform Langevin dynamic numerical simulation on a double-well potential
system subjected to an asymmetric saw-tooth type external time varying field
and white noise forces. The hysteresis loss calculated from the first-passage
time distribution obtained shows asymmetric behaviour with respect to the
asymmetry in the field sweep. The hysteresis loss, in our model, being a
measure of the synchronized passages from one well to the other, indicates
asymmetric "correlated" passages in the two opposing directions when driven by
a temporally asymmetric external field in the presence of white noise
(fluctuating) forces. The implication of our results on the phenomena of
predominantly unidirectional motion of a Brownian particle in a symmetric
periodic (nonratchet-like) potential is discussed.
