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Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons
In the same way as the energy density associated with the tensor modes of the geometry modifies the evolution of the curvature perturbations, the scalar modes may also indirectly affect the cosmic backgrounds of relic gravitons by inducing higher-order corrections that are only superficially gauge-i...
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Lenguaje: | eng |
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2020
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Acceso en línea: | https://dx.doi.org/10.1142/S0217751X20501651 http://cds.cern.ch/record/2723975 |
_version_ | 1780965959041810432 |
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author | Giovannini, Massimo |
author_facet | Giovannini, Massimo |
author_sort | Giovannini, Massimo |
collection | CERN |
description | In the same way as the energy density associated with the tensor modes of the geometry modifies the evolution of the curvature perturbations, the scalar modes may also indirectly affect the cosmic backgrounds of relic gravitons by inducing higher-order corrections that are only superficially gauge-invariant. This spurious gauge-invariance gets manifest when the effective anisotropic stresses, computed in different coordinate systems, are preliminarily expressed in a form that only depends on the curvature inhomogeneities defined on comoving orthogonal hypersurfaces and on their corresponding time derivatives. Using this observation we demonstrate in general terms that the higher-order contributions derived in diverse coordinate systems coincide when the wavelengths are smaller than the sound horizon defining the evolution of the curvature inhomogeneities but they lead to sharply different results in the opposite limit. A similar drawback arises when the energy density of the relic gravitons is derived from competing energy–momentum pseudotensors and should be consistently taken into account in the related phenomenological discussions. |
id | cern-2723975 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2020 |
record_format | invenio |
spelling | cern-27239752023-10-04T07:56:44Zdoi:10.1142/S0217751X20501651http://cds.cern.ch/record/2723975engGiovannini, MassimoSpurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitonshep-phParticle Physics - Phenomenologygr-qcGeneral Relativity and Cosmologyastro-ph.COAstrophysics and Astronomyhep-thParticle Physics - TheoryIn the same way as the energy density associated with the tensor modes of the geometry modifies the evolution of the curvature perturbations, the scalar modes may also indirectly affect the cosmic backgrounds of relic gravitons by inducing higher-order corrections that are only superficially gauge-invariant. This spurious gauge-invariance gets manifest when the effective anisotropic stresses, computed in different coordinate systems, are preliminarily expressed in a form that only depends on the curvature inhomogeneities defined on comoving orthogonal hypersurfaces and on their corresponding time derivatives. Using this observation we demonstrate in general terms that the higher-order contributions derived in diverse coordinate systems coincide when the wavelengths are smaller than the sound horizon defining the evolution of the curvature inhomogeneities but they lead to sharply different results in the opposite limit. A similar drawback arises when the energy density of the relic gravitons is derived from competing energy–momentum pseudotensors and should be consistently taken into account in the related phenomenological discussions.In the same way as the energy density associated with the tensor modes of the geometry modifies the evolution of the curvature perturbations, the scalar modes may also indirectly affect the cosmic backgrounds of relic gravitons by inducing higher-order corrections that are only superficially gauge-invariant. This spurious gauge-invariance gets manifest when the effective anisotropic stresses, computed in different coordinate systems, are preliminarily expressed in a form that only depends on the curvature inhomogeneities defined on comoving orthogonal hypersurfaces and on their corresponding time derivatives. Using this observation we demonstrate in general terms that the higher-order contributions derived in diverse coordinate systems coincide when the wavelengths are smaller than the sound horizon defining the evolution of the curvature inhomogeneities but they lead to sharply different results in the opposite limit. A similar drawback arises when the energy density of the relic gravitons is derived from competing energy-momentum pseudo-tensors and should be consistently taken into account in the related phenomenological discussions.arXiv:2005.04962oai:cds.cern.ch:27239752020-05-11 |
spellingShingle | hep-ph Particle Physics - Phenomenology gr-qc General Relativity and Cosmology astro-ph.CO Astrophysics and Astronomy hep-th Particle Physics - Theory Giovannini, Massimo Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
title | Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
title_full | Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
title_fullStr | Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
title_full_unstemmed | Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
title_short | Spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
title_sort | spurious gauge-invariance of higher-order contributions to the spectral energy density of the relic gravitons |
topic | hep-ph Particle Physics - Phenomenology gr-qc General Relativity and Cosmology astro-ph.CO Astrophysics and Astronomy hep-th Particle Physics - Theory |
url | https://dx.doi.org/10.1142/S0217751X20501651 http://cds.cern.ch/record/2723975 |
work_keys_str_mv | AT giovanninimassimo spuriousgaugeinvarianceofhigherordercontributionstothespectralenergydensityoftherelicgravitons |