Stochastic resonance in coupled weakly-damped bistable oscillators subjected to additive and multiplicative noises

With coupled weakly-damped periodically driven bistable oscillators subjected to additive and multiplicative noises under concern, the objective of this paper is to check to what extent the resonant point predicted by the Gaussian distribution assumption can approximate the simulated one. The investigation based on the dynamical mean-field approximation and the direct simulation demonstrates that the predicted resonant point and the simulated one are basically coincident for the case of pure additive noise, but for the case including multiplicative noise the situation becomes somewhat complex. Specifically speaking, when stochastic resonance (SR) is observed by changing the additive noise intensity, the predicted resonant point is lower than the simulated one; nevertheless, when SR is observed by changing the multiplicative noise intensity, the predicted resonant point is higher than the simulated one. Our observations imply that the Gaussian distribution assumption can not exactly describe the actual situation, but it is useful to some extent in predicting the low-frequency stochastic resonance of the coupled weakly-damped bistable oscillator.