Stochastic resonance induced weak signal enhancement over controllable potential-well asymmetry

A dynamical model submerged in two colored multiplicative and additive noises by colored cross-correlation is established to elaborate controllable asymmetric potential-well with depth-asymmetry and width-asymmetry. We deduce the approximate signal-to-noise ratio (SNR) as widely adopted indicator for quantifying stochastic resonance (SR) behavior in accordance with the two-state theory, where the largest SNR peaks are almost attained in the asymmetry case. Moreover, the non-monotonic resonance curves excited by the incremental multiplicative colored noise intensity show the typical SR phenomenon and the SNR peaks decline as the additive colored noise intensity increases, the SR behavior induced by multiplicative colored noise is different from that induced by varying additive one. Noteworthy, the self-correlation time of alternative noises are more effective for controlling SR than cross-correlation time of noises. More interestingly, the output SNR demonstrates double resonance peaks by varying the cross-correlation intensity from negative to positive, however, the two local optimal cross-correlation intensities are almost maintained constant as the increasing of additive noise intensity. Even the large asymmetric well-depth is always beneficial to the improvement of SNR in comparison with well-width asymmetry at the same situation, which is due to the much more energy harvesting from the noises.