Optimal signal response: From classical resonance to quenched disorder resonance

In recent years, the positive roles of noise and disorder in collective behaviors have received increasing attention. Among them, stochastic resonance-like stimulus response triggered by noise or disorder is one of the most counterintuitive phenomena. Such a resonance reveals that the response of a system to weak driving can be maximally improved by adding a proper dose of noise or disorder. Furthermore, this phenomenon is closely related to classical resonance wherein the maximum response emerges in the condition of the driving frequency equals the inherent frequency of the system. However, the debate concerning whether stochastic resonance is a genuine resonance has never stopped. In the present mini-review, we briefly review the history of resonance, from classical resonance to the quenched disorder resonance, and investigate both the differences and relations from the viewpoint of the singularity of the response function. Besides, we introduce the essence of the latest manifestation of stochastic resonance: quenched disorder resonance, stating its significance for both the optimal mutual information in the realistic inferior olive and the stochastic resonance debate. Finally, we succinctly discuss some unresolved issues in resonance study and the significance of addressing them.