SIGNAL-TO-NOISE RATIO IN STOCHASTIC RESONANCE
We solve the Fokker-Planck equation for an overdamped Brownian particle in a periodically forced bistable potential by means of a path integral method, obtaining the propagators in the steepest-descent (small-noise) approximation. We compute the long-times asymptotic probability distribution, the asymptotic correlation functions, and the time-averaged spectral density, which allows us the immediate calculation of the signal to noise ratio, a directly measurable quantity useful to characterize the phenomenon of stochastic resonance. Our numerical algorithm is fast and runs on a desktop computer, and the results agree with experiments and with former theoretical calculations of the amplification factor; in addition it allows us to calculate the experimentally more accessible signal to noise ratio.