Subthreshold Stochastic Resonance: Rectangular signals can cause anomalous large gains

TL;DR

This paper investigates stochastic resonance in noisy bistable systems driven by subthreshold rectangular signals, revealing conditions under which SR can produce gains exceeding unity, highlighting nonlinear response effects.

Contribution

It demonstrates that subthreshold rectangular signals can induce stochastic resonance with SR-gains above one, a novel insight into nonlinear system responses.

Findings

SR-gains exceeding unity under specific pulse durations

Non-monotonic behavior of SR quantifiers with noise strength

Enhanced understanding of nonlinearity in SR phenomena

Abstract

The main objective of this work is to explore aspects of stochastic resonance (SR) in noisy bistable, symmetric systems driven by subthreshold periodic rectangular external signals possessing a large duty cycle of unity. Using a precise numerical solution of the Langevin equation, we carry out a detailed analysis of the behavior of the first two cumulant averages, the correlation function and its coherent and incoherent parts. We also depict the non-monotonic behavior versus the noise strength of several SR quantifiers such as the average output amplitude, i.e. the spectral amplification (SPA), the signal-to-noise ratio (SNR) and the SR-gain. In particular, we find that with subthreshold amplitudes and for an appropriate duration of the pulses of the driving force the phenomenon of stochastic resonance (SR), is accompanied by SR-gains exceeding unity. This analysis thus sheds new light onto the interplay between nonlinearity and the nonlinear response which in turn yields nontrivial, unexpected SR-gains above unity.