Postquench relaxation dynamics of Gross-Neveu lattice fermions

We study the quantum relaxation dynamics for a lattice version of the one-dimensional <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mi>N</a:mi> </a:math> -flavor Gross-Neveu model after a Hamiltonian parameter quench. Allowing for a system-reservoir coupling <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:mi>γ</b:mi> </b:math> , we numerically describe the system dynamics through a time-dependent self-consistent Lindblad master equation. For a closed ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mrow> <c:mi>γ</c:mi> <c:mo>=</c:mo> <c:mn>0</c:mn> </c:mrow> </c:math> ) finite-size system subjected to an interaction parameter quench, the order parameter dynamics exhibits oscillations and revivals. In the thermodynamic limit, our results imply that the order parameter reaches its postquench stationary value in accordance with the eigenstate thermalization hypothesis. However, time-dependent finite-momentum correlation matrix elements equilibrate only if <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:mrow> <d:mi>γ</d:mi> <d:mo>&gt;</d:mo> <d:mn>0</d:mn> </d:mrow> </d:math> . Our findings are consistent with the system being described by a pertinent generalized Gibbs ensemble and, accordingly, highlight subtle yet important aspects of the postquench relaxation dynamics of quantum many-body systems.