Cosmological perturbations from stochastic gravity

In inflationary cosmological models driven by an inflaton field the origin of the primordial inhomogeneities which are responsible for large-scale structure formation are the quantum fluctuations of the inflaton field. These are usually calculated using the standard theory of cosmological perturbati...

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Detalhes bibliográficos
Autores: Roura Crumols, Albert, Verdaguer Oms, Enric, 1950-
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2008
País:España
Recursos:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/12383
Acesso em linha:https://hdl.handle.net/2445/12383
Access Level:acceso abierto
Palavra-chave:Pertorbació (Astronomia)
Cosmologia
Gravetat quàntica
Teoria quàntica de camps
Perturbation (Astronomy)
Cosmology
Quantum gravity
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spelling Cosmological perturbations from stochastic gravityRoura Crumols, AlbertVerdaguer Oms, Enric, 1950-Pertorbació (Astronomia)CosmologiaGravetat quànticaTeoria quàntica de campsPerturbation (Astronomy)CosmologyQuantum gravityIn inflationary cosmological models driven by an inflaton field the origin of the primordial inhomogeneities which are responsible for large-scale structure formation are the quantum fluctuations of the inflaton field. These are usually calculated using the standard theory of cosmological perturbations, where both the gravitational and the inflaton fields are linearly perturbed and quantized. The correlation functions for the primordial metric fluctuations and their power spectrum are then computed. Here we introduce an alternative procedure for calculating the metric correlations based on the Einstein-Langevin equation which emerges in the framework of stochastic semiclassical gravity. We show that the correlation functions for the metric perturbations that follow from the Einstein-Langevin formalism coincide with those obtained with the usual quantization procedures when the scalar field perturbations are linearized. This method is explicitly applied to a simple model of chaotic inflation consisting of a Robertson-Walker background, which undergoes a quasi-de Sitter expansion, minimally coupled to a free massive quantum scalar field. The technique based on the Einstein-Langevin equation can, however, deal naturally with the perturbations of the scalar field even beyond the linear approximation, as is actually required in inflationary models which are not driven by an inflaton field, such as Starobinsky¿s trace-anomaly driven inflation or when calculating corrections due to nonlinear quantum effects in the usual inflaton driven models.The American Physical Society2008info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/12383Articles publicats en revistes (Física de la Matèria Condensada)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésReproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevD.78.064010Physical Review D, 2008, vol. 78, núm. 6, p. 064010-1-064010-27http://dx.doi.org/10.1103/PhysRevD.78.064010(c) The American Physical Society, 2008info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/123832026-05-27T06:46:51Z
dc.title.none.fl_str_mv Cosmological perturbations from stochastic gravity
title Cosmological perturbations from stochastic gravity
spellingShingle Cosmological perturbations from stochastic gravity
Roura Crumols, Albert
Pertorbació (Astronomia)
Cosmologia
Gravetat quàntica
Teoria quàntica de camps
Perturbation (Astronomy)
Cosmology
Quantum gravity
title_short Cosmological perturbations from stochastic gravity
title_full Cosmological perturbations from stochastic gravity
title_fullStr Cosmological perturbations from stochastic gravity
title_full_unstemmed Cosmological perturbations from stochastic gravity
title_sort Cosmological perturbations from stochastic gravity
dc.creator.none.fl_str_mv Roura Crumols, Albert
Verdaguer Oms, Enric, 1950-
author Roura Crumols, Albert
author_facet Roura Crumols, Albert
Verdaguer Oms, Enric, 1950-
author_role author
author2 Verdaguer Oms, Enric, 1950-
author2_role author
dc.subject.none.fl_str_mv Pertorbació (Astronomia)
Cosmologia
Gravetat quàntica
Teoria quàntica de camps
Perturbation (Astronomy)
Cosmology
Quantum gravity
topic Pertorbació (Astronomia)
Cosmologia
Gravetat quàntica
Teoria quàntica de camps
Perturbation (Astronomy)
Cosmology
Quantum gravity
description In inflationary cosmological models driven by an inflaton field the origin of the primordial inhomogeneities which are responsible for large-scale structure formation are the quantum fluctuations of the inflaton field. These are usually calculated using the standard theory of cosmological perturbations, where both the gravitational and the inflaton fields are linearly perturbed and quantized. The correlation functions for the primordial metric fluctuations and their power spectrum are then computed. Here we introduce an alternative procedure for calculating the metric correlations based on the Einstein-Langevin equation which emerges in the framework of stochastic semiclassical gravity. We show that the correlation functions for the metric perturbations that follow from the Einstein-Langevin formalism coincide with those obtained with the usual quantization procedures when the scalar field perturbations are linearized. This method is explicitly applied to a simple model of chaotic inflation consisting of a Robertson-Walker background, which undergoes a quasi-de Sitter expansion, minimally coupled to a free massive quantum scalar field. The technique based on the Einstein-Langevin equation can, however, deal naturally with the perturbations of the scalar field even beyond the linear approximation, as is actually required in inflationary models which are not driven by an inflaton field, such as Starobinsky¿s trace-anomaly driven inflation or when calculating corrections due to nonlinear quantum effects in the usual inflaton driven models.
publishDate 2008
dc.date.none.fl_str_mv 2008
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/12383
url https://hdl.handle.net/2445/12383
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevD.78.064010
Physical Review D, 2008, vol. 78, núm. 6, p. 064010-1-064010-27
http://dx.doi.org/10.1103/PhysRevD.78.064010
dc.rights.none.fl_str_mv (c) The American Physical Society, 2008
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) The American Physical Society, 2008
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv The American Physical Society
publisher.none.fl_str_mv The American Physical Society
dc.source.none.fl_str_mv Articles publicats en revistes (Física de la Matèria Condensada)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,300719

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