Quantum quenches and thermalization in one-dimensional fermionic systems

We study the dynamics and thermalization of strongly correlated fermions in finite one-dimensional lattices after a quantum quench. Our calculations are performed using exact diagonalization. We focus on one- and two-body observables such as the momentum distribution function [n (k)] and the density-density structure factor [N (k)], respectively, and study the effects of approaching an integrable point. We show that while the relaxation dynamics and thermalization of N (k) for fermions is very similar to the one of hardcore bosons, the behavior of n (k) is distinctively different. The latter observable exhibits a slower relaxation dynamics in fermionic systems. We identify the origin of this behavior, which is related to the off-diagonal matrix elements of n (k) in the basis of the eigenstates of the Hamiltonian. More generally, we find that thermalization occurs far away from integrability and that it breaks down as one approaches the integrable point.