Local Thermal Equilibrium States in Relativistic Quantum Field Theory

TL;DR

This paper discusses a new approach to characterizing local thermal equilibrium states in relativistic quantum field theory using a generalized KMS condition, connecting it to existing proposals for local thermal states.

Contribution

It introduces a generalized KMS condition for non-equilibrium states with local thermal properties, linking it to prior characterizations of local thermal equilibrium.

Findings

Proposes a generalized KMS condition for local thermal states

Connects the new proposal with existing local thermal equilibrium frameworks

Addresses the challenge of characterizing non-equilibrium states in QFT

Abstract

It is well-known that thermal equilibrium states in quantum statistical mechanics and quantum field theory can be described in a mathematically rigorous manner by means of the so-called Kubo-Martin-Schwinger (KMS) condition, which is based on certain analyticity and periodicity properties of correlation functions. On the other hand, the characterization of non-equilibrium states which only locally have thermal properties still constitutes a challenge in quantum field theory. We discuss a recent proposal for characterization of such states by a generalized KMS condition. The connection of this proposal to a proposal by D. Buchholz, I. Ojima and H.-J. Roos for characterizing local thermal equilibrium states in quantum field theory is discussed.