Observation of stochastic resonance for weak periodic magnetic field signal using a chaotic system

Abstract

[eng] Stochastic resonance, found in many natural and engineered bistable systems, refers to a physical phenomenon wherein the response of nonlinear dynamical systems to weak input signal is enhanced by the presence of noise, tuned to the optimal level. However, the observation of this phenomenon for weak subthreshold periodic magnetic field signals in chaotic bistable systems has not been reported. In this paper we present the experimental observation of stochastic resonance in a Chua circuit. The experiment was performed using an internal Gaussian noise source, and an external driving subthreshold sinusoidal magnetic field below 1mT, with a frequency range in the order of kHz. The circuit was operating near the switching threshold between single-scroll and double-scroll chaotic regimes. The spectral characteristics of interest (the output signal power at forcing signal frequency and the signal-to-noise ratio) pass through a maximum with varying noise intensity. The residence times probability distribution quantifying the synchronization between the forcing and the response has a multi-peaked structure for the optimal noise intensity. Our experiments show the possibility of stochastic resonance for weak subthreshold magnetic field signals in chaotic systems, with parts of the attractor located in different regions of the phase space and with internal noise.