Quasi-particle spectrum and entanglement generation after a quench in the quantum Potts spin chain

TL;DR

This paper investigates how the quasi-particle spectrum influences entanglement entropy production after a quench in the quantum Potts spin chain, revealing a link between new excitations and increased entanglement.

Contribution

It extends the understanding of entanglement dynamics by analyzing non-integrable quenches in the Potts model, showing the relation between quasiparticle spectrum changes and entanglement growth.

Findings

Sudden increase in entanglement production rate linked to new quasiparticle excitations.

The effect is general and relates to the non-equilibrium Gibbs paradox.

Supports the interpretation of entanglement growth as mixing entropy.

Abstract

Recently, a non-trivial relation between the quasi-particle spectrum and entanglement entropy production was discovered in non-integrable quenches in the paramagnetic Ising quantum spin chain. Here we study the dynamics of analogous quenches in the quantum Potts spin chain. Tuning the parameters of the system, we observe a sudden increase in the entanglement production rate, which is shown to be related to the appearance of new quasiparticle excitations in the post-quench spectrum. Our results demonstrate the generality of the effect and support its interpretation as the non-equilibrium version of the well-known Gibbs paradox related to mixing entropy which appears in systems with a non-trivial quasi-particle spectrum.