Statistical Physics and Condensed Matter

Glassy Dynamics

Heinz Horner, Reimer Kühn, W. Zippold


Relaxtion times in spin-glasses or glasses are observed to grow to such an extent at low temperatures that these systems do not reach thermal equilibrium on experimentally accessible time-scales. Properties of such systems are then often found to depend on their history of preparation; such systems are said to age. Similar observations are made in coarsening dynamics at first order phase transitions. Some properties of spin-glasses and glasses must therefore be studied via dynamical approaches which allow taking possible history dependence explicitly into account. Fluctuation dissipation theorems which connect correlation and response functions in thermal equilibrium are found to be broken in aging systems. We are studying simple models of spin-glasses in order to understand, in particular, their dynamics on long time scales. Some of these models exhibit dynamical freezing transitions without undergoing a thermodynamic phase transition. It is believed that such a scenario is occurring also in the much less well-understood case of the glass-transition in structural glasses.

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