Applicability of the generalized Gibbs ensemble after a quench in the quantum Isingchain

Abstract

We investigate the out-of-equilibrium dynamics of the one-dimensional quantum Isingmodel after a sudden quench in the transverse magnetic field. While for a translationallyinvariant system the statistical description of the asymptotic order parametercorrelations after the quench can be performed in terms of the generalized Gibbsensemble, we show that a breaking of translational invariance, e.g. by perturbing theboundary conditions, disrupts its validity. This effect, which of course vanishesin the thermodynamic limit, is shown to be very important in the presence ofdisorder.