PUB - Publikationen an der Universität Bielefeld

We consider the common spin-1/2 XX model in one dimension with open boundary conditions and a large but finite number of spins. The system is in thermal equilibrium at times t < 0, and is subject to a weak local perturbation (quantum quench) at t = 0. Focusing mainly on single-spin perturbations and observables, we show that the system rethermalizes for sufficiently large times t > 0 without invoking any unproven assumptions besides the basic laws of quantum mechanics. Moreover, the time-dependent relaxation behavior is obtained in quantitative detail and is found to exhibit a wealth of interesting features.