A comment on finite temperature correlations in integrable QFT

TL;DR

This paper evaluates and extends Leclair and Mussardo's proposal for finite temperature correlation functions in integrable quantum field theories, confirming its validity for one-point functions of conserved quantities and challenging its applicability to higher-point functions.

Contribution

The paper provides additional justification for the proposal's accuracy in one-point functions and presents counterexamples showing its limitations for multi-point functions.

Findings

Validates the proposal for one-point functions of conserved quantities.

Identifies limitations of the proposal for two- and higher-point functions.

Provides counterexamples to demonstrate the proposal's inaccuracy in certain cases.

Abstract

I discuss and extend the recent proposal of Leclair and Mussardo for finite temperature correlation functions in integrable QFTs. I give further justification for its validity in the case of one point functions of conserved quantities. I also argue that the proposal is not correct for two (and higher) point functions, and give some counterexamples to justify that claim.