Thermally activated escape far from equilibrium: A unified path-integral approach

Thermally activated escape over potential barriers is addressed for systems driven out of equilibrium by time-dependent forces, temperatures, or dissipation coefficients of rather general type. Particular examples are periodic perturbations, single pulses, and the initial convergence towards Kramers rate in a time-independent set up. The general problem is treated within one common, unifying path-integral approach in the simplest case of an overdamped, one-dimensional model dynamics. As an application, the following quite astonishing effect is demonstrated: for a suitably chosen, but still quite simple static potential landscape, the net escape rate may be substantially reduced by temporally increasing the temperature above its unperturbed, constant level. (C) 2010 Elsevier B.V. All rights reserved.