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DY: Fachverband Dynamik und Statistische Physik

DY 22: Statistical Physics (general)

DY 22.7: Vortrag

Mittwoch, 2. April 2014, 16:45–17:00, ZEU 160

From the nonstationarity of the hysteresis memory to a nonstationary response — •Sven Schubert and Günter Radons — TU Chemnitz, 09107 Chemnitz, Germany

A certain memory causes the dependence on the history of an external field and the multistability which are typical features of systems with hysteresis. We consider the number of values N_t stored by hysteresis models, like the Preisach model and the zero-temperature random field Ising model, which are subjected to uncorrelated stationary driving.
The time-dependent probability distribution P_t(N) of the memory length is derived using methods known from record statistics. It is shown that the memory length is on average diverging with time t. Thus, the hysteresis memory caused by uncorrelated stationary noise becomes a nonstationary process, even in the long-time limit.
The nonstationarity of the memory is reflected, for instance, in possible long-time tails in the autocovariance of the stationary response of the Preisach model [1]. Furthermore, the hysteretic response can become a nonstationary process with stationary increments leading on to 1/f-noise. We elucidate this mechanism using an example of the symmetric Preisach model and present rigorous results on the power spectral density of the model’s response to uncorrelated driving.
[1] G. Radons, Phys. Rev. Lett. 100, 240602 (2008).