title: Quantum quench in the transverse-field Ising chain.
abstract: We consider the time evolution of observables in the transverse-field Ising chain after a sudden quench of the magnetic field. We provide exact analytical results for the asymptotic time and distance dependence of one- and two-point correlation functions of the order parameter. We employ two complementary approaches based on asymptotic evaluations of determinants and form-factor sums. We prove that the stationary value of the two-point correlation function is not thermal, but can be described by a generalized Gibbs ensemble (GGE). The approach to the stationary state can also be understood in terms of a GGE. We present a conjecture on how these results generalize to particular quenches in other integrable models.
authors.affiliation: Dipartimento di Fisica dell'Università di Pisa and INFN, Pisa, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Calabrese
authors.forename: Fabian H L
authors.initials: FH
authors.lastname: Essler
authors.forename: Maurizio
authors.initials: M
authors.lastname: Fagotti