# Local Thermal Equilibrium and KMS states in Curved Spacetime

November 02, 2012

On the example of a free massless and conformally coupled scalar field, it is
argued that in quantum field theory in curved spacetimes with time-like Killing
field, the corresponding KMS states (generalized Gibbs ensembles) at parameter
$\beta>0$ need not possess a definite temperature in the sense of the zeroth law.
In fact, these states, although passive in the sense of the second law, are not
always in local thermal equilibrium (LTE). A criterion characterizing LTE
states with sharp local temperature is discussed. Moreover, a proposal is made
for fixing the renormalization freedom of composite fields which serve as
"thermal observables" and a new definition of the thermal energy of LTE states
is introduced. Based on these results a general relation between the local
temperature and the parameter \beta is established for KMS states in (Anti) de
Sitter spacetime.

open access link
Class. Quantum Grav. 29 (2012) 245015

@article{Solveen:2012ai,
author = "Solveen, Christoph",
title = "{Local Thermal Equilibrium and KMS states in Curved
Spacetime}",
journal = "Class. Quant. Grav.",
volume = "29",
year = "2012",
pages = "245015",
doi = "10.1088/0264-9381/29/24/245015",
eprint = "1211.0431",
archivePrefix = "arXiv",
primaryClass = "gr-qc",
SLACcitation = "%%CITATION = ARXIV:1211.0431;%%"
}

Keywords:

local thermal equilibrium, QFT on curved spacetimes