Off-Equilibrium Dynamics at Very Low Temperatures in 3d Spin Glasses

We present a high statistic systematic study of the overlap correlation function well below the critical temperature in the three dimensional Gaussian spin glass. The off-equilibrium correlation function has been studied confirming the power law behavior for the dynamical correlation length. In particular we have computed the dynamical critical exponent z in a wide range of temperatures, $0.35 \le T \le 0.9$, obtaining a dependence z(T)=6.2/T in a very good agreement with recent experiments. Moreover, we report a study of the violation of the fluctuation-dissipation theorem for very low temperatures T=0.5 and T=0.35. All our numerical results avoid a droplet model interpretation even when T is as low as T=0.35.