Ageing in spin-glasses in three, four and infinite dimensions

Abstract

The SUE machine is used to extend by a factor of 1000 the time-scale of previous studies of the aging, out-of-equilibrium dynamics of the Edwards-Anderson model with binary couplings, on large lattices (L = 60). The correlation function, C(t+t_(w), t_(w)), t_(w) being the time elapsed under a quench from high-temperature, follows nicely a slightly-modified power law for t > t_(w). Very tiny (logarithmic), yet clearly detectable deviations from the full-aging t/t_(w) scaling can be observed. Furthermore, the t < t_(w) data shows clear indications of the presence of more than one time-sector in the aging dynamics. Similar results are found in four-dimensions, but a rather different behaviour is obtained in the infinite-dimensional z = 6 Viana-Bray model. Most surprisingly, our results in infinite dimensions seem incompatible with dynamical ultrametricity. A detailed study of the link correlation function is presented, suggesting that its aging-properties are the same as for the spin correlation-function.