1212.3367 (Lorenzo Campos Venuti et al.)

Equilibration times in clean and noisy systems    [PDF]

Lorenzo Campos Venuti, Sunil Yeshwanth, Stephan Haas

We study the equilibration dynamics of closed finite quantum systems and address the question of the time needed for the system to equilibrate. In particular, we focus on the scaling of the equilibration time with the system size. For clean systems, we give general arguments predicting the equilibration time for clustering initial states and for small quenches around a critical point. We then analyze noisy systems where exponentially large time scales are known to exist. Specifically, we consider the tight-binding model with diagonal impurities and give numerical evidence for the existence of these exponentially scaling equilibration times. Finally, we consider another noisy system whose evolution dynamics is randomly sampled from a circular unitary ensemble. Here, we are able to prove analytically that the relaxation times scales as O(1), thus showing that noise alone is not sufficient for slow equilibration dynamics.

View original: http://arxiv.org/abs/1212.3367