Interaction enhancement effect in a simple system of two coupled discrete stochastic resonators

We investigate a simple system of two coupled discrete stochastic resonators in the following two cases, to clarify the role of coupling. Case A: an oscillating force is applied to the whole system. Case B: an oscillating force is applied to one of the coupled resonators. We have obtained analytical expressions for the amplitude of a single resonator and the local and the global signal-to-noise ratios (SNRs) in cases A and B. The second resonator without external force in case B is found to show stochastic resonance through the interaction as it should be, and the resonance temperatures at which the stochastic resonance occurs are different from each other. The local SNR in case A shows an interaction enhancement effect (namely, stochastic resonance is enhanced by the interaction in a certain case), while the global SNR does not show this effect (as was shown in other chains constructed of two-state discrete resonators).