THERMALLY ACTIVATED ESCAPE WITH POTENTIAL FLUCTUATIONS DRIVEN BY AN ORNSTEIN-UHLENBECK PROCESS

We study the mean escape time ($) over bar T of an overdamped Brownian particle in a metastable potential that is subject to additive Gaussian white noise (thermal noise) and multiplicative Ornstein-Uhlenbeck:noise (potential fluctuations). We derive two very general simple conditions for the existence of ''resonant activation,'' i.e., a minimum of ($) over bar T as a function of the correlation time tau of the potential fluctuations. In the case of small thermal and potential fluctuations, we investigate ($) over bar T(tau) for large tau by means of a kinetic model and the remaining tau regime by means of quasipotential theory. We find three different types of ''resonant activation'' a standard type, a type that typically occurs for potentials without fluctuations near the barrier and the well, and a mixed type.