Local-energy approach to the dynamic glass transition

Departament de Fisica Fonamental, Facultat de Fisica, Universitat de Barcelona Diagonal 647, 08028 Barcelona, Spain

Received: 3 May 2006
Accepted: 17 July 2006

Abstract

We propose a new class of phenomenological models for dynamic glass transitions. The system consists of an ensemble of mesoscopic regions to which local energies are allocated. At each time step, a region is randomly chosen and a new local energy is drawn from a distribution that self-consistently depends on the global energy of the system. Then, the transition is accepted or not according to the Metropolis rule. Within this scheme, we model an energy threshold leading to a mode-coupling glass transition as in the p-spin model. The glassy dynamics is characterized by a two-step relaxation of the energy autocorrelation function. The aging scaling is fully determined by the evolution of the global energy and linear violations of the fluctuation dissipation relation are found for observables uncorrelated with the energies. Interestingly, our mean-field approach has a natural extension to finite dimension, that we briefly discuss.