Warm Inflation with Pseudo-scalar Couplings

Fuente: arXiv
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Autori principali: Broadberry, Edward, Hook, Anson, Mondal, Sagnik
Natura: Preprint
Pubblicazione: 2025
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author Broadberry, Edward
Hook, Anson
Mondal, Sagnik
author_facet Broadberry, Edward
Hook, Anson
Mondal, Sagnik
contents Inflaton couplings during warm inflation result in the production of a thermal bath. Thermal friction and fluctuations can dominate the standard de Sitter analogues, resulting in a modified slow-roll scenario with a new source of density fluctuations. Due to issues with back-reaction, it is advantageous to consider inflaton couplings with the thermal bath that are pseudo-scalar in nature, e.g., derivative interactions or topological $F \tilde F$ couplings. We demonstrate that {\it every single} existing model of warm inflation utilizing pseudo-scalar couplings needs to be corrected to properly account for all of the chemical potentials that the thermal bath acquires in response to the inflaton coupling. These chemical potentials are for non-conserved charges, and are non-zero only because of the applied inflaton couplings. The model-dependent chemical potentials modify the fluctuation-dissipation theorem, making the relationship between the thermal friction and thermal fluctuations model-dependent. In extreme cases, these chemical potentials can cause the friction term to vanish while thermal fluctuations remain non-zero. In the context of a simple example, we demonstrate how to calculate the chemical potentials, thermal friction, and thermal fluctuations using both the Boltzmann equations and by calculating thermal expectation values, showing explicitly that the two approaches give the same result.
format Preprint
id arxiv_https___arxiv_org_abs_2505_07943
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Warm Inflation with Pseudo-scalar Couplings
Broadberry, Edward
Hook, Anson
Mondal, Sagnik
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
Inflaton couplings during warm inflation result in the production of a thermal bath. Thermal friction and fluctuations can dominate the standard de Sitter analogues, resulting in a modified slow-roll scenario with a new source of density fluctuations. Due to issues with back-reaction, it is advantageous to consider inflaton couplings with the thermal bath that are pseudo-scalar in nature, e.g., derivative interactions or topological $F \tilde F$ couplings. We demonstrate that {\it every single} existing model of warm inflation utilizing pseudo-scalar couplings needs to be corrected to properly account for all of the chemical potentials that the thermal bath acquires in response to the inflaton coupling. These chemical potentials are for non-conserved charges, and are non-zero only because of the applied inflaton couplings. The model-dependent chemical potentials modify the fluctuation-dissipation theorem, making the relationship between the thermal friction and thermal fluctuations model-dependent. In extreme cases, these chemical potentials can cause the friction term to vanish while thermal fluctuations remain non-zero. In the context of a simple example, we demonstrate how to calculate the chemical potentials, thermal friction, and thermal fluctuations using both the Boltzmann equations and by calculating thermal expectation values, showing explicitly that the two approaches give the same result.
title Warm Inflation with Pseudo-scalar Couplings
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
url https://arxiv.org/abs/2505.07943