FRAGILE-GLASS BEHAVIOR OF A SHORT-RANGE P-SPIN MODEL

We propose a short-range generalization of the p-spin interaction spin -glass model. The model is well suited to test the idea that an entrop y collapse is at the bottom line of the dynamical singularity encounte red in structural glasses. The model is studied in three dimensions th rough Monte Carlo simulations, which put in evidence fragile glass beh avior with stretched exponential relaxation and super-Arrhenius behavi or of the relaxation time. Our data are in favor of a Vogel-Fulcher be havior of the relaxation time, related to an entropy collapse at the K auzmann temperature. We, however, encounter difficulties analogous to those found in experimental systems when extrapolating thermodynamical data at low temperatures. We study the spin-glass susceptibility, inv estigating the behavior of the correlation length in the system. We fi nd that the increase of the relaxation time is accompanied by a very s low growth of the correlation length. We discuss the scaling propertie s of off-equilibrium dynamics in the glassy regime, finding qualitativ e agreement with the mean-field theory.