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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todo:paper_24700010_v97_n2_p_MironGranese2023-10-03T16:42:11Z Primordial gravitational waves amplification from causal fluids Miron-Granese, N. Calzetta, E. 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_24700010_v97_n2_p_MironGranese |
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Universidad de Buenos Aires |
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I-28 |
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R-134 |
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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. |
| format |
JOUR |
| author |
Miron-Granese, N. Calzetta, E. |
| spellingShingle |
Miron-Granese, N. Calzetta, E. Primordial gravitational waves amplification from causal fluids |
| author_facet |
Miron-Granese, N. Calzetta, E. |
| author_sort |
Miron-Granese, N. |
| title |
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 |
| url |
http://hdl.handle.net/20.500.12110/paper_24700010_v97_n2_p_MironGranese |
| work_keys_str_mv |
AT mirongranesen primordialgravitationalwavesamplificationfromcausalfluids AT calzettae primordialgravitationalwavesamplificationfromcausalfluids |
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1807322900517093376 |