The stochastic resonance in a system of gradient type

The time behavior of a coupled, parity-conserving, two-dimensional system of gradient type, perturbed by a Wiener process and forced by an external periodic component added to one of the two state variables, is here studied. Minimum energy paths joining stable steady states are estimated using the string method. The system is found to exhibit stochastic resonance behavior with unexpected large amplification, compared with the classical one-dimensional case, for values of the coupling constant ranging between -1 and 0. The mechanism seems to survive also when the system is not strictly of gradient type ( a perturbative rotational component does not affect the occurrence of the stochastic amplification). Finally, the implications of the present analysis on the stochastic climate model, originally developed to explain ice ages transitions, are addressed.