Eur. Phys. J. B 37, 47-53 (2004)
https://doi.org/10.1140/epjb/e2004-00029-9

Off equilibrium dynamics in the 2d-XY system

Laboratoire de Physique des Matériaux, UMR CNRS No. 7556, Université Henri Poincaré (Nancy 1), B.P. 239, 54506 Vandœuvre-lès-Nancy Cedex, France

Corresponding author: ^a karevski@lpm.u-nancy.fr

Received: 15 September 2003
Published online: 19 February 2004

Abstract

We study the non-equilibrium time evolution of the classical XY spin model in two dimensions. The two-time autocorrelation and linear response functions are considered for systems initially prepared in a high temperature state and in a completely ordered state. After a quench into the critical phase, we use Monte Carlo simulations to determine the time-evolution of these quantities, and we deduce the temperature dependence of the slope of the parametric plot susceptibility/correlation in the asymptotic regime. This slope is usually identified with the infinite fluctuation-dissipation ratio, which measures the extent of violation of the equilibrium fluctuation-dissipation theorem. However, a direct measure of this ratio leads to a vanishing value.