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De Sitter stability and coarse graining

We present a 4-dimensional back reaction analysis of de Sitter space for a conformally coupled scalar field in the presence of vacuum energy initialized in the Bunch–Davies vacuum. In contrast to the usual semi-classical prescription, as the source term in the Friedmann equations we use expectation...

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Autor principal: Markkanen, T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560872/
https://www.ncbi.nlm.nih.gov/pubmed/31258396
http://dx.doi.org/10.1140/epjc/s10052-018-5575-9
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author Markkanen, T.
author_facet Markkanen, T.
author_sort Markkanen, T.
collection PubMed
description We present a 4-dimensional back reaction analysis of de Sitter space for a conformally coupled scalar field in the presence of vacuum energy initialized in the Bunch–Davies vacuum. In contrast to the usual semi-classical prescription, as the source term in the Friedmann equations we use expectation values where the unobservable information hidden by the cosmological event horizon has been neglected i.e. coarse grained over. It is shown that in this approach the energy-momentum is precisely thermal with constant temperature despite the dilution from the expansion of space due to a flux of energy radiated from the horizon. This leads to a self-consistent solution for the Hubble rate, which is gradually evolving and at late times deviates significantly from de Sitter. Our results hence imply de Sitter space to be unstable in this prescription. The solution also suggests dynamical vacuum energy: the continuous flux of energy is balanced by the generation of negative vacuum energy, which accumulatively decreases the overall contribution. Finally, we show that our results admit a thermodynamic interpretation which provides a simple alternate derivation of the mechanism. For very long times the solutions coincide with flat space.
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spelling pubmed-65608722019-06-26 De Sitter stability and coarse graining Markkanen, T. Eur Phys J C Part Fields Regular Article - Theoretical Physics We present a 4-dimensional back reaction analysis of de Sitter space for a conformally coupled scalar field in the presence of vacuum energy initialized in the Bunch–Davies vacuum. In contrast to the usual semi-classical prescription, as the source term in the Friedmann equations we use expectation values where the unobservable information hidden by the cosmological event horizon has been neglected i.e. coarse grained over. It is shown that in this approach the energy-momentum is precisely thermal with constant temperature despite the dilution from the expansion of space due to a flux of energy radiated from the horizon. This leads to a self-consistent solution for the Hubble rate, which is gradually evolving and at late times deviates significantly from de Sitter. Our results hence imply de Sitter space to be unstable in this prescription. The solution also suggests dynamical vacuum energy: the continuous flux of energy is balanced by the generation of negative vacuum energy, which accumulatively decreases the overall contribution. Finally, we show that our results admit a thermodynamic interpretation which provides a simple alternate derivation of the mechanism. For very long times the solutions coincide with flat space. Springer Berlin Heidelberg 2018-02-02 2018 /pmc/articles/PMC6560872/ /pubmed/31258396 http://dx.doi.org/10.1140/epjc/s10052-018-5575-9 Text en © The Author(s) 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Funded by SCOAP3
spellingShingle Regular Article - Theoretical Physics
Markkanen, T.
De Sitter stability and coarse graining
title De Sitter stability and coarse graining
title_full De Sitter stability and coarse graining
title_fullStr De Sitter stability and coarse graining
title_full_unstemmed De Sitter stability and coarse graining
title_short De Sitter stability and coarse graining
title_sort de sitter stability and coarse graining
topic Regular Article - Theoretical Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560872/
https://www.ncbi.nlm.nih.gov/pubmed/31258396
http://dx.doi.org/10.1140/epjc/s10052-018-5575-9
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