Quantum quench in the sine-Gordon model

TL;DR

This paper studies the time evolution of a specific quantum field theory after a quench, showing exponential decay of a key observable using form-factor methods, with implications for integrable models.

Contribution

It introduces two form-factor based methods to analyze the dynamics of the sine-Gordon model post-quench, generalizable to other correlation functions and integrable systems.

Findings

The one-point function decays exponentially over time.

Decay rate is analytically determined.

Methods applicable to other correlation functions and models.

Abstract

We consider the time evolution in the repulsive sine-Gordon quantum field theory after the system is prepared in a particular class of initial states. We focus on the time dependence of the one-point function of the semi-local operator $\exp\big(i\ \beta \ \Phi(x)/2\big)$. By using two different methods based on form-factor expansions, we show that this expectation value decays to zero exponentially, and we determine the decay rate by analytical means. Our methods generalise to other correlation functions and integrable models.