Relaxation through an asymmetric fluctuating potential barrier.
We revise the problem of thermally activated crossing of a fluctuating potential barrier, laying stress on the asymmetry of the barrier. Considering as a working model a paradigmatic triangular dichotomously varying potential landscape we find an atypical dependence of the mean first-passage time on the correlation time tau of fluctuations. Namely, in the range of small tau an additional maximum appears. We propose a qualitative explanation of this feature emphasizing the relevance of dynamics in the vicinity of the barrier top, i.e., recrossing, which generally has not been recognized by this time in this particular context. Moreover, we observe that addition of fast barrier fluctuations of some finite intensity needs not to increase the relaxation rate, as has been indicated many times in extensive studies related to the resonant activation phenomenon. Our findings are confirmed numerically for some other systems.
Wozinski
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A
Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Toruń, Poland. olov@fizyka.umk.pl
Iwaniszewski
J
J