Stretched exponential relaxation in the Coulomb glass

The relaxation of the specific heat and the entropy to their equilibrium values is investigated numerically for the three-dimensional Coulomb glass at very low temperatures. The long time relaxation follows a stretched exponential function, f(t) = f0 exp −(t/ ) , with the exponent increasing with the temperature. The relaxation time follows an Arrhenius behavior divergence when T → 0. A relation between the specific heat and the entropy in the long time regime is found.This work was supported by the European TMR Network- Fractals (Contract No. FMRXCT980183). A. Díaz-Sánchez acknowledges support from a Postdoctoral Grant from the European TMR Network-Fractals. We are indebted to M. Ortuño, A. Möbius, M. Pollak, and A. Coniglio for stimulating discussions