Universality of the REM for dynamics of mean-field spin glasses

Abstract

We consider a version of a Glauber dynamics for a p-spin Sherrington--Kirkpatrick model of a spin glass that can be seen as a time change of simple random walk on the N-dimensional hypercube. We show that, for any p>2 and any inverse temperature \beta>0, there exist constants g>0, such that for all exponential time scales, $\exp(\gamma N)$, with $\gamma< g$, the properly rescaled clock process (time-change process), converges to an \alpha-stable subordinator where \alpha=\gamma/\beta^2<1. Moreover, the dynamics exhibits aging at these time scales with time-time correlation function converging to the arcsine law of this \alpha-stable subordinator. In other words, up to rescaling, on these time scales (that are shorter than the equilibration time of the system), the dynamics of p-spin models ages in the same way as the REM, and by extension Bouchaud's REM-like trap model, confirming the latter as a universal aging mechanism for a wide range of systems. The SK model (the case p=2) seems to belong to a different universality class.