Entanglement Spreading and Generalized Hydrodynamics

Vincenzo Alba, Bruno Bertini, Maurizio Fagotti

Published 2019-03-01Version 1

Understanding the spreading of entanglement in out-of-equilibrium quantum many-body systems is currently regarded as the key to unravel how equilibrium statistical mechanics emerges from quantum dynamics. Here we investigate the dynamics of bipartite entanglement after a quench from piecewise homogeneous initial states in interacting integrable models. By combining the quasiparticle picture for the entanglement spreading with Generalised Hydrodynamics we derive an analytical prediction for the dynamics of the entanglement entropy between a finite subsystem and the rest. In particular, we show that the entanglement production rate depends only on the physics at the interface between the two halves of the system. Interestingly, the entanglement production rate differs from the rate of exchange of thermodynamic entropy. This contrasts with what happens in free systems or in homogeneous interacting integrable systems, where they coincide.