Diffusion in fluctuating media: resonant activation

We study the dynamics of a system of particles diffusing in a fluctuating medium: a lattice which can be in two states, with transitions among them induced by a combination of a periodic deterministic and a stochastic process. We characterize the problem studying the mean first passage time (MFPT), the probability of return to the origin (Ps0), and the number of visited lattice sites. We observe a double resonant activation-like phenomenon when we plot the MFPT and Ps0 as functions of the intensity of the transition rate stochastic component.