Analysis of noise spectral density and coherence resonance phenomena in mixed hysteretic systems driven by noise

The characterization of a hysteretic system response to noise is a challenging problem due to the complexity of the non-Markovian process found as the system output. The recent development of the mathematical theory to describe stochastic processes defined on graphs has provided the framework to analytically calculate the noise spectral density for Preisach hysteretic models [1]. Numerical simulations performed by using Monte Carlo methods have generalized the spectral analysis to other hysteretic models, such as Jiles-Atherton, Coleman-Hodgdon, Energetic and Bouc-Wen model and offered significant insights into this problem [2]. Moreover, stochastic resonance phenomena have been thus identified in complex hysteretic systems subject to a noisy sinusoidal input, when certain conditions are satisfied by the amplitude of the deterministic signal and noise strength [2-4]. These constructive effects of noise seems counter-intuitive but they are nevertheless often found in nonlinear systems and their applications are spreading across various areas of science and engineering. In fact, it is well-known in magnetic community that thermal noise is playing a positive role in achieving higher magnetic storage densities by using heat assisted magnetic recording (HAMR) technology.