Dresden 2006 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 21: Statistical Physics (general) I

DY 21.5: Vortrag

Dienstag, 28. März 2006, 11:00–11:15, SCH 251

Mesoscopic fluctuations and intermittency in aging dynamics — •Paolo Sibani — Fysisk Institut, SDU, Campusvej 55, DK5230 Odense M

Mesoscopic aging systems are characterized by large intermittent noise fluctuations. In a record dynamics scenario [P. Sibani and J. Dall, Europhys. Lett. 64, 2003] these events, or quakes, are treated as a Poisson process with average α ln(1 + t/t_w), where t is the observation time, t_w is the age and α 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 α, 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/t_w and becomes sharply peaked in the thermodynamic limit. Its average and variance, which are given analytically, depend on t/t_w as a power-law and a power-law with a logarithmic correction, respectively. Most predictions are in good agreement with recent data from the literature and with the simulations of the Edwards-Anderson spin glass carried out as a test.