Off equilibrium dynamics in the 3d-XY system

We investigate through Monte Carlo simulations the non-equilibrium behaviour of the three-dimensional XY-model quenched from a high temperature state to its ferromagnetic and critical phases. The two-times autocorrelation and response functions are determined in the asymptotic (scaling) regime, from which the nonequilibrium exponents and critical are extracted. The form of the scaling function is in agreement with the prediction of local scale-invariance. The so-called limit fluctuation-dissipation ratio is shown to vanish in the ordered phase and to reach a constant value around 0.43 for the critical quench.Received: 12 July 2004, Published online: 30 September 2004PACS: 75.40.Gb Dynamic properties - 05.70.Ln Non-equilibrium and irreversible thermodynamics