Aging and nonlinear glassy dynamics in a mean field model
Abstract
The mean field approach of glassy dynamics successfully describes systems which are outofequilibrium in their low temperature phase. In some cases an aging behaviour is found, with no stationary regime ever reached. In the presence of dissipative forces however, the dynamics is indeed stationary, but still outofequilibrium, as inferred by a significant violation of the fluctuation dissipation theorem. The mean field dynamics of a particle in a random but shortrange correlated environment, offers the opportunity of observing both the aging and driven stationary regimes. Using a geometrical approach previously introduced by the author, we study here the relation between these two situations, in the pure relaxational limit, i.e. the zero temperature case. In the stationary regime, the velocity (v)force (F) characteristics is a power law v F^{4}, while the characteristic times scale like powers of v, in agreement with an early proposal by Horner. The crossover between the aging, linearresponse regime and the nonlinear stationary regime is smooth, and we propose a parametrization of the correlation functions valid in both cases, by means of an ``effective time''. We conclude that aging and nonlinear response are dual manifestations of a single outofequilibrium state, which might be a generic situation.
 Publication:

European Physical Journal B
 Pub Date:
 2001
 DOI:
 10.1007/s100510170350
 arXiv:
 arXiv:condmat/0005162
 Bibcode:
 2001EPJB...19...65T
 Keywords:

 05.70.Ln;
 64.70.Pf;
 75.10.Nr;
 83.50.Gd;
 Nonequilibrium and irreversible thermodynamics;
 Glass transitions;
 Spinglass and other random models;
 Condensed Matter
 EPrint:
 15 pages, 7 figures, submitted to European Journal of Physics B