Late-time large-distance asymptotics of the transverse correlation functions of the XX chain in the space-like regime

TL;DR

This paper derives an explicit formula for the dominant behavior of the transverse correlation function in the XX chain at late times and large distances, valid across various temperatures and magnetic fields.

Contribution

It provides the first explicit late-time, large-distance asymptotic expression for the transverse correlation function in the XX chain in the spacelike regime, using a form factor series analysis.

Findings

Explicit late-time asymptotics valid for all non-zero temperatures.

Results applicable for magnetic fields below saturation.

Demonstrates the effectiveness of the form factor series approach.

Abstract

We derive an explicit expression for the leading term in the late-time, large-distance asymptotic expansion of a transverse dynamical two-point function of the XX chain in the spacelike regime. This expression is valid for all non-zero finite temperatures and for all magnetic fields below the saturation threshold. It is obtained here by means of a straightforward term-by-term analysis of a thermal form factor series, derived in previous work, and demonstrates the usefulness of the latter.