Cargando…
Blue and violet graviton spectra from a dynamical refractive index
We show that the spectral energy distribution of relic gravitons mildly increases for frequencies smaller than the μHz and then flattens out whenever the refractive index of the tensor modes is dynamical during a quasi-de Sitter stage of expansion. For a conventional thermal history the high-frequen...
Autor principal: | |
---|---|
Lenguaje: | eng |
Publicado: |
2018
|
Materias: | |
Acceso en línea: | https://dx.doi.org/10.1016/j.physletb.2018.12.068 http://cds.cern.ch/record/2319226 |
_version_ | 1780958407393542144 |
---|---|
author | Giovannini, Massimo |
author_facet | Giovannini, Massimo |
author_sort | Giovannini, Massimo |
collection | CERN |
description | We show that the spectral energy distribution of relic gravitons mildly increases for frequencies smaller than the μHz and then flattens out whenever the refractive index of the tensor modes is dynamical during a quasi-de Sitter stage of expansion. For a conventional thermal history the high-frequency plateau ranges between the mHz and the audio band but it is supplemented by a spike in the GHz region if a stiff post-inflationary phase precedes the standard radiation-dominated epoch. Even though the slope is blue at intermediate frequencies, it may become violet in the MHz window. For a variety of post-inflationary histories, including the conventional one, a dynamical index of refraction leads to a potentially detectable spectral energy density in the kHz and in the mHz regions while all the relevant phenomenological constraints are concurrently satisfied. |
id | cern-2319226 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 2018 |
record_format | invenio |
spelling | cern-23192262023-03-14T20:16:22Zdoi:10.1016/j.physletb.2018.12.068http://cds.cern.ch/record/2319226engGiovannini, MassimoBlue and violet graviton spectra from a dynamical refractive indexhep-thParticle Physics - Theoryhep-phParticle Physics - Phenomenologygr-qcGeneral Relativity and Cosmologyastro-ph.COAstrophysics and AstronomyWe show that the spectral energy distribution of relic gravitons mildly increases for frequencies smaller than the μHz and then flattens out whenever the refractive index of the tensor modes is dynamical during a quasi-de Sitter stage of expansion. For a conventional thermal history the high-frequency plateau ranges between the mHz and the audio band but it is supplemented by a spike in the GHz region if a stiff post-inflationary phase precedes the standard radiation-dominated epoch. Even though the slope is blue at intermediate frequencies, it may become violet in the MHz window. For a variety of post-inflationary histories, including the conventional one, a dynamical index of refraction leads to a potentially detectable spectral energy density in the kHz and in the mHz regions while all the relevant phenomenological constraints are concurrently satisfied.We show that the spectral energy distribution of relic gravitons mildly increases for frequencies smaller than the $\mu$Hz and then flattens out whenever the refractive index of the tensor modes is dynamical during a quasi-de Sitter stage of expansion. For a conventional thermal history the high-frequency plateau ranges between the mHz and the audio band but it is supplemented by a spike in the GHz region if a stiff post-inflationary phase precedes the standard radiation-dominated epoch. Even though the slope is blue at intermediate frequencies, it may become violet in the MHz window. For a variety of post-inflationary histories, including the conventional one, a dynamical index of refraction leads to a potentially detectable spectral energy density in the kHz and in the mHz regions while all the relevant phenomenological constraints are concurrently satisfied.arXiv:1805.08142CERN-TH-2018-106oai:cds.cern.ch:23192262018-05-21 |
spellingShingle | hep-th Particle Physics - Theory hep-ph Particle Physics - Phenomenology gr-qc General Relativity and Cosmology astro-ph.CO Astrophysics and Astronomy Giovannini, Massimo Blue and violet graviton spectra from a dynamical refractive index |
title | Blue and violet graviton spectra from a dynamical refractive index |
title_full | Blue and violet graviton spectra from a dynamical refractive index |
title_fullStr | Blue and violet graviton spectra from a dynamical refractive index |
title_full_unstemmed | Blue and violet graviton spectra from a dynamical refractive index |
title_short | Blue and violet graviton spectra from a dynamical refractive index |
title_sort | blue and violet graviton spectra from a dynamical refractive index |
topic | hep-th Particle Physics - Theory hep-ph Particle Physics - Phenomenology gr-qc General Relativity and Cosmology astro-ph.CO Astrophysics and Astronomy |
url | https://dx.doi.org/10.1016/j.physletb.2018.12.068 http://cds.cern.ch/record/2319226 |
work_keys_str_mv | AT giovanninimassimo blueandvioletgravitonspectrafromadynamicalrefractiveindex |