Relaxation Dynamics of Disordered Spin Chains: Localization and the   Existence of a Stationary State
  We study the unitary relaxation dynamics of disordered spin chains following a sudden quench of the Hamiltonian. We give analytical arguments, corroborated by specific numerical examples, to show that the existence of a stationary state depends crucially on the spectral and localization properties of the final Hamiltonian, and not on the initial state. We test these ideas on integrable one-dimensional models of the Ising or XY class, but argue more generally on their validity for more complex (nonintegrable) models. 
Simone Ziraldo, Alessandro Silva, Giuseppe E. Santoro
cond-mat.dis-nn cond-mat.stat-mech