Time Evolution of the Symmetry Resolved Entanglement Entropy after a Mass Quench

TL;DR

This paper computes the out-of-equilibrium dynamics of symmetry resolved entanglement entropy after a mass quench in the Ising field theory, revealing linear growth and oscillatory corrections, using form factor techniques.

Contribution

It provides the first explicit quantum field theory calculation of symmetry resolved entropy dynamics post-quench using twist fields.

Findings

Symmetry resolved entropy grows linearly with time.

Oscillatory corrections appear in the entropy evolution.

Results align with quasiparticle picture predictions.

Abstract

In this paper we investigate the properties of the symmetry resolved entanglement entropy after a mass quench in the Ising field theory. Since the theory is free and the post-quench state known explicitly, the one-point function of the relevant (composite) branch point twist field can be computed using form factor techniques, similar to previous work on the branch point twist field and the magnetisation, respectively. We find that the symmetry resolved entropy grows linearly in time at the same rate as the total entropy, and that there are sub-leading oscillatory corrections. This result provides the first explicit computation of the out-of-equilibrium dynamics of the symmetry resolved entropy employing twist fields in quantum field theory and is consistent with existing results based on the quasiparticle picture.