Finite temperature expectation values of boundary operators

TL;DR

This paper proposes a conjecture for calculating thermal expectation values of boundary operators in integrable boundary quantum field theories, verified through low-temperature expansion techniques with applications in condensed matter and string theory.

Contribution

It introduces a new conjecture relating boundary operator expectation values to form factors, verified by finite size techniques, advancing the analysis of boundary phenomena in quantum field theories.

Findings

Conjecture accurately predicts thermal one-point functions.

Verification through low-temperature expansion confirms the formula.

Method enables evaluation of higher point functions in boundary settings.

Abstract

A conjecture is presented for the thermal one-point function of boundary operators in integrable boundary quantum field theories in terms of form factors. It is expected to have applications in studying boundary critical phenomena and boundary flows, which are relevant in the context of condensed matter and string theory. The conjectured formula is verified by a low-temperature expansion developed using finite size techniques, which can also be used to evaluate higher point functions both in the bulk and on the boundary.