Synchronized First-Passages in a Double-Well System

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.