# Entanglement evolution and generalised hydrodynamics: interacting integrable systems

## TL;DR

This paper combines quasiparticle picture and Generalised Hydrodynamics to analytically predict entanglement dynamics after a junction in interacting integrable systems, revealing unique entanglement rate behaviors at the interface.

## Contribution

It introduces an analytical framework for entanglement evolution in interacting integrable models using GHD and quasiparticles, highlighting interface-dependent entanglement rates.

## Key findings

- Entanglement rate depends only on interface physics.
- Entanglement rate differs from thermodynamic entropy exchange.
- Contrasts with free and homogeneous integrable systems.

## Abstract

We investigate the dynamics of bipartite entanglement after the sudden junction of two leads 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. We find that the entanglement rate between the two leads depends only on the physics at the interface and differs from the rate of exchange of thermodynamic entropy. This contrasts with the behaviour in free or homogeneous interacting integrable systems, where the two rates coincide.