Mesoscopic fluctuations and intermittency in aging dynamicsP. Sibani
Fysisk Institut, SDU - DK-5230 Odense M, Denmark
received 7 June 2005; accepted in final form 27 October 2005
published online 23 November 2005
Mesoscopic aging systems are characterized by large intermittent noise fluctuations. In a record dynamics scenario (SIBANI P. and DALL J., Europhys. Lett., 64 (2003) 8) these events, quakes, are treated as a Poisson process with average , where t is the observation time, tw is the age and is a parameter. Assuming for simplicity that quakes constitute the only source of de-correlation, we present a model for the probability density function (PDF) of the configuration autocorrelation function. Beside , the model has the average quake size 1/q as a parameter. The model autocorrelation PDF has a Gumbel-like shape, which approaches a Gaussian for large t/tw and becomes sharply peaked in the thermodynamic limit. Its average and variance, which are given analytically, depend on t/tw as a power law and a power law with a logarithmic correction, respectively. Most predictions are in good agreement with data from the literature and with the simulations of the Edwards-Anderson spin-glass carried out as a test.
65.60.+a - Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
75.10.Nr - Spin-glass and other random models.
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