

Preprint 54/2015
KMS-like Properties of Local Thermal Equilibrium States in Quantum Field Theory
Michael Gransee, Nicola Pinamonti, and Rainer Verch
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Submission date: 30. Aug. 2015
Pages: 32
published in: Journal of geometry and physics, 117 (2017), p. 15-35
DOI number (of the published article): 10.1016/j.geomphys.2017.02.014
Bibtex
Keywords and phrases: local thermal equilibrium, Quantum Field Theory, KMS condition, Quantum Statistical Mechanics
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Abstract:
A new condition, called “Local KMS Condition”, characterizing states of a quantum field
to which one can ascribe, at a given spacetime point, a temperature, is introduced in this
article. It will be shown that the Local KMS Condition (LKMS condition) is equivalent to the
Local Thermal Equilibrium (LTE) condition, proposed previously by Buchholz, Ojima and
Roos, for states of the quantized scalar Klein-Gordon field that fulfill the analytic microlocal
spectrum condition. Therefore, known examples of states fulfilling the LTE condition provide
examples of states obeying the LKMS condition with a temperature distribution varying in
space and time. The results extend to the generalized cases of mixed-temperature LKMS
and LTE states. The LKMS condition therefore provides a promising generalization of the
KMS condition, which characterizes global thermal equilibrium states with respect to an
inertial time evolution, to states which are globally out of equilibrium but still possess a
local temperature distribution.