Primordial gravitational waves amplification from causal fluids

We consider the evolution of the gravitational wave spectrum for super-Hubble modes in interaction with a relativistic fluid, which is regarded as an effective description of fluctuations in a light scalar minimally coupled field, during the earliest epoch of the radiation dominated era after the en...

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Publicado: 2018
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_24700010_v97_n2_p_MironGranese
http://hdl.handle.net/20.500.12110/paper_24700010_v97_n2_p_MironGranese
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paper:paper_24700010_v97_n2_p_MironGranese2023-06-08T16:36:37Z Primordial gravitational waves amplification from causal fluids We consider the evolution of the gravitational wave spectrum for super-Hubble modes in interaction with a relativistic fluid, which is regarded as an effective description of fluctuations in a light scalar minimally coupled field, during the earliest epoch of the radiation dominated era after the end of inflation. We obtain the initial conditions for gravitons and fluid from quantum fluctuations at the end of inflation, and assume instantaneous reheating. We model the fluid by using relativistic causal hydrodynamics. There are two dimensionful parameters, the relaxation time τ and temperature. In particular we study the interaction between gravitational waves and the nontrivial tensor (spin 2) part of the fluid energy-momentum tensor. Our main result is that the new dimensionful parameter τ introduces a new relevant scale which distinguishes two kinds of super-Hubble modes. For modes with H-1<λ<τ the fluid-graviton interaction increases the amplitude of the primordial gravitational wave spectrum at the electroweak transition by a factor of about 1.3 with respect to the usual scale invariant spectrum. © 2018 American Physical Society. 2018 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_24700010_v97_n2_p_MironGranese http://hdl.handle.net/20.500.12110/paper_24700010_v97_n2_p_MironGranese
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description We consider the evolution of the gravitational wave spectrum for super-Hubble modes in interaction with a relativistic fluid, which is regarded as an effective description of fluctuations in a light scalar minimally coupled field, during the earliest epoch of the radiation dominated era after the end of inflation. We obtain the initial conditions for gravitons and fluid from quantum fluctuations at the end of inflation, and assume instantaneous reheating. We model the fluid by using relativistic causal hydrodynamics. There are two dimensionful parameters, the relaxation time τ and temperature. In particular we study the interaction between gravitational waves and the nontrivial tensor (spin 2) part of the fluid energy-momentum tensor. Our main result is that the new dimensionful parameter τ introduces a new relevant scale which distinguishes two kinds of super-Hubble modes. For modes with H-1<λ<τ the fluid-graviton interaction increases the amplitude of the primordial gravitational wave spectrum at the electroweak transition by a factor of about 1.3 with respect to the usual scale invariant spectrum. © 2018 American Physical Society.
title Primordial gravitational waves amplification from causal fluids
spellingShingle Primordial gravitational waves amplification from causal fluids
title_short Primordial gravitational waves amplification from causal fluids
title_full Primordial gravitational waves amplification from causal fluids
title_fullStr Primordial gravitational waves amplification from causal fluids
title_full_unstemmed Primordial gravitational waves amplification from causal fluids
title_sort primordial gravitational waves amplification from causal fluids
publishDate 2018
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_24700010_v97_n2_p_MironGranese
http://hdl.handle.net/20.500.12110/paper_24700010_v97_n2_p_MironGranese
_version_ 1768545714958237696

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