One-loop infrared rescattering by enhanced scalar fluctuations during inflation

Fuente: arXiv
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Auteurs principaux: Fumagalli, Jacopo, Bhattacharya, Sukannya, Peloso, Marco, Renaux-Petel, Sébastien, Witkowski, Lukas T.
Format: Preprint
Publié: 2023
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author Fumagalli, Jacopo
Bhattacharya, Sukannya
Peloso, Marco
Renaux-Petel, Sébastien
Witkowski, Lukas T.
author_facet Fumagalli, Jacopo
Bhattacharya, Sukannya
Peloso, Marco
Renaux-Petel, Sébastien
Witkowski, Lukas T.
contents We show that, whenever the perturbations of some field are excited during inflation by a physical process on sub-horizon scales, they unavoidably generate, even through gravitational interactions alone, a significant resonant IR cascade of power down to scales that are of the order of the horizon at that time (we denote these scales as near IR). We provide general analytic one-loop results for the enhancement of the IR power of the curvature perturbation generated by this effect, highlighting the role played by the resonance. We then study a number of examples in which the excited state is: (i) an isocurvature field, (ii) the curvature perturbation itself, (iii) a mixture of curvature and isocurvature fluctuations driven to an excited state by their coupled dynamics. In the cases shown, the cascade significantly modifies the near IR part of the power spectrum of the curvature perturbation with respect to the linear theory, indicating that this effect can impact the phenomenology associated with a variety of mechanisms considered in the literature, notably concerning primordial black holes and gravitational waves.
format Preprint
id arxiv_https___arxiv_org_abs_2307_08358
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle One-loop infrared rescattering by enhanced scalar fluctuations during inflation
Fumagalli, Jacopo
Bhattacharya, Sukannya
Peloso, Marco
Renaux-Petel, Sébastien
Witkowski, Lukas T.
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
We show that, whenever the perturbations of some field are excited during inflation by a physical process on sub-horizon scales, they unavoidably generate, even through gravitational interactions alone, a significant resonant IR cascade of power down to scales that are of the order of the horizon at that time (we denote these scales as near IR). We provide general analytic one-loop results for the enhancement of the IR power of the curvature perturbation generated by this effect, highlighting the role played by the resonance. We then study a number of examples in which the excited state is: (i) an isocurvature field, (ii) the curvature perturbation itself, (iii) a mixture of curvature and isocurvature fluctuations driven to an excited state by their coupled dynamics. In the cases shown, the cascade significantly modifies the near IR part of the power spectrum of the curvature perturbation with respect to the linear theory, indicating that this effect can impact the phenomenology associated with a variety of mechanisms considered in the literature, notably concerning primordial black holes and gravitational waves.
title One-loop infrared rescattering by enhanced scalar fluctuations during inflation
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2307.08358