Canonical structure and extra mode of generalized unimodular gravity
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFLA |
Texto Completo: | http://repositorio.ufla.br/jspui/handle/1/34807 |
Resumo: | We consider a recently proposed generalization of unimodular gravity, where the lapse function is constrained to be equal to a function of the determinant of the spatial metric fðhÞ, as a potential origin of a dark fluid with a generally h-dependent equation of state parameter. We establish the Hamiltonian analysis and the canonical path integral for the theory. All the special cases that do not match unimodular gravity involve the violation of general covariance, and consequently the physical content of the theory is changed significantly. Particularly, the case of a constant function f is shown to contain an extra physical degree of freedom in each point of space. Physical consequences of the extra degree of freedom are studied in a linearized theory, where the extra mode is carried by the trace of the metric perturbation. The trace mode does not propagate as a wave, since it satisfies an elliptic partial differential equation in spacetime. Consequently, the trace perturbation is shown to grow exponentially with time, which implies instability. The case of a general fðhÞ involves additional second-class constraints, which implies the presence of an extra global degree of freedom that depends only on time (instead of the extra local degree of freedom in the case of a constant f). |
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Canonical structure and extra mode of generalized unimodular gravityWe consider a recently proposed generalization of unimodular gravity, where the lapse function is constrained to be equal to a function of the determinant of the spatial metric fðhÞ, as a potential origin of a dark fluid with a generally h-dependent equation of state parameter. We establish the Hamiltonian analysis and the canonical path integral for the theory. All the special cases that do not match unimodular gravity involve the violation of general covariance, and consequently the physical content of the theory is changed significantly. Particularly, the case of a constant function f is shown to contain an extra physical degree of freedom in each point of space. Physical consequences of the extra degree of freedom are studied in a linearized theory, where the extra mode is carried by the trace of the metric perturbation. The trace mode does not propagate as a wave, since it satisfies an elliptic partial differential equation in spacetime. Consequently, the trace perturbation is shown to grow exponentially with time, which implies instability. The case of a general fðhÞ involves additional second-class constraints, which implies the presence of an extra global degree of freedom that depends only on time (instead of the extra local degree of freedom in the case of a constant f).American Physical Society2019-06-18T13:19:04Z2019-06-18T13:19:04Z2018-02info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfBUFALO, R.; OKSANEN, M. Canonical structure and extra mode of generalized unimodular gravity. Physical Review D, [S.l.], v. 97, n. 4, Feb. 2018.http://repositorio.ufla.br/jspui/handle/1/34807Physical Review Dreponame:Repositório Institucional da UFLAinstname:Universidade Federal de Lavras (UFLA)instacron:UFLAAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/info:eu-repo/semantics/openAccessBufalo, RodrigoOksanen, Markkueng2023-05-09T17:35:53Zoai:localhost:1/34807Repositório InstitucionalPUBhttp://repositorio.ufla.br/oai/requestnivaldo@ufla.br || repositorio.biblioteca@ufla.bropendoar:2023-05-09T17:35:53Repositório Institucional da UFLA - Universidade Federal de Lavras (UFLA)false |
dc.title.none.fl_str_mv |
Canonical structure and extra mode of generalized unimodular gravity |
title |
Canonical structure and extra mode of generalized unimodular gravity |
spellingShingle |
Canonical structure and extra mode of generalized unimodular gravity Bufalo, Rodrigo |
title_short |
Canonical structure and extra mode of generalized unimodular gravity |
title_full |
Canonical structure and extra mode of generalized unimodular gravity |
title_fullStr |
Canonical structure and extra mode of generalized unimodular gravity |
title_full_unstemmed |
Canonical structure and extra mode of generalized unimodular gravity |
title_sort |
Canonical structure and extra mode of generalized unimodular gravity |
author |
Bufalo, Rodrigo |
author_facet |
Bufalo, Rodrigo Oksanen, Markku |
author_role |
author |
author2 |
Oksanen, Markku |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Bufalo, Rodrigo Oksanen, Markku |
description |
We consider a recently proposed generalization of unimodular gravity, where the lapse function is constrained to be equal to a function of the determinant of the spatial metric fðhÞ, as a potential origin of a dark fluid with a generally h-dependent equation of state parameter. We establish the Hamiltonian analysis and the canonical path integral for the theory. All the special cases that do not match unimodular gravity involve the violation of general covariance, and consequently the physical content of the theory is changed significantly. Particularly, the case of a constant function f is shown to contain an extra physical degree of freedom in each point of space. Physical consequences of the extra degree of freedom are studied in a linearized theory, where the extra mode is carried by the trace of the metric perturbation. The trace mode does not propagate as a wave, since it satisfies an elliptic partial differential equation in spacetime. Consequently, the trace perturbation is shown to grow exponentially with time, which implies instability. The case of a general fðhÞ involves additional second-class constraints, which implies the presence of an extra global degree of freedom that depends only on time (instead of the extra local degree of freedom in the case of a constant f). |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-02 2019-06-18T13:19:04Z 2019-06-18T13:19:04Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
BUFALO, R.; OKSANEN, M. Canonical structure and extra mode of generalized unimodular gravity. Physical Review D, [S.l.], v. 97, n. 4, Feb. 2018. http://repositorio.ufla.br/jspui/handle/1/34807 |
identifier_str_mv |
BUFALO, R.; OKSANEN, M. Canonical structure and extra mode of generalized unimodular gravity. Physical Review D, [S.l.], v. 97, n. 4, Feb. 2018. |
url |
http://repositorio.ufla.br/jspui/handle/1/34807 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
American Physical Society |
publisher.none.fl_str_mv |
American Physical Society |
dc.source.none.fl_str_mv |
Physical Review D reponame:Repositório Institucional da UFLA instname:Universidade Federal de Lavras (UFLA) instacron:UFLA |
instname_str |
Universidade Federal de Lavras (UFLA) |
instacron_str |
UFLA |
institution |
UFLA |
reponame_str |
Repositório Institucional da UFLA |
collection |
Repositório Institucional da UFLA |
repository.name.fl_str_mv |
Repositório Institucional da UFLA - Universidade Federal de Lavras (UFLA) |
repository.mail.fl_str_mv |
nivaldo@ufla.br || repositorio.biblioteca@ufla.br |
_version_ |
1807835206340575232 |