Gravitational Waves from the Hagedorn Phase

Fuente: arXiv
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Auteur principal: Villa, Gonzalo
Format: Preprint
Publié: 2024
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author Villa, Gonzalo
author_facet Villa, Gonzalo
contents We illustrate the main points behind the computation of the gravitational wave spectrum originated from a phase in the early universe where the energy density is dominated by highly excited fundamental string degrees of freedom - a Hagedorn phase. This phase is described using the Boltzmann equation approach to string thermodynamics, which we illustrate via a toy model which permits analytic computations for the evolution of perturbations. This window into the out-of-equilibrium regime allows us to compute equilibration rates and conclude that, in realistic scenarios, long, open strings dominate the ensemble, source gravitational waves and provide a succesful reheating. Furthermore, we compare the results against the Standard Model prediction for a gravitational wave background of thermal origin and conclude that the string prediction is larger. This is one of the few cases in which a signal of stringy origin dominates over the field theory analogue. This work is based on arXiv:2310.11494 and arXiv:2408.13803 and is a contribution to the Proceedings of the 29th symposium on Particles, Strings and Cosmology (PASCOS 2024).
format Preprint
id arxiv_https___arxiv_org_abs_2410_07350
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gravitational Waves from the Hagedorn Phase
Villa, Gonzalo
High Energy Physics - Theory
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
We illustrate the main points behind the computation of the gravitational wave spectrum originated from a phase in the early universe where the energy density is dominated by highly excited fundamental string degrees of freedom - a Hagedorn phase. This phase is described using the Boltzmann equation approach to string thermodynamics, which we illustrate via a toy model which permits analytic computations for the evolution of perturbations. This window into the out-of-equilibrium regime allows us to compute equilibration rates and conclude that, in realistic scenarios, long, open strings dominate the ensemble, source gravitational waves and provide a succesful reheating. Furthermore, we compare the results against the Standard Model prediction for a gravitational wave background of thermal origin and conclude that the string prediction is larger. This is one of the few cases in which a signal of stringy origin dominates over the field theory analogue. This work is based on arXiv:2310.11494 and arXiv:2408.13803 and is a contribution to the Proceedings of the 29th symposium on Particles, Strings and Cosmology (PASCOS 2024).
title Gravitational Waves from the Hagedorn Phase
topic High Energy Physics - Theory
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2410.07350