Periodic force-enhanced decay of a metastable state: A case of stochastic resonance in a spatially extended system

We suggest a simple model of stochastic resonance in a spatially extended s ystem that could be approximately treated analytically and compared to dire ct simulation. It consists of a one-dimensional, sinusoidally driven decay of a metastable state, in the presence of white noise, held between two abs orbing walls. The latter mimic potential barriers. The total flow through e ither barrier exhibits an optimal dependence on frequency of the force fiel d related to the intrinsic parameters of the system. This sinusoidal forcin g induces a break in the left-right symmetry. An application is suggested t o gel electrophoresis of polyelectrolytes, possibly DNA. (C) 1998 Elsevier Science B.V.