Inflation with Gauss-Bonnet correction: beyond slow-roll

Fuente: arXiv
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Main Authors: Mudrunka, Kamil, Nakayama, Kazunori
Format: Preprint
Published: 2025
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author Mudrunka, Kamil
Nakayama, Kazunori
author_facet Mudrunka, Kamil
Nakayama, Kazunori
contents If a coupling between the inflaton and the Gauss-Bonnet term is introduced, many models of inflation that were ruled out by the most recent Planck data can be made viable again. The predictions for the scalar spectral index and tensor-to-scalar ratio are typically computed using the slow-roll approximation. In this paper we instead study the full equations of motion and determine the necessary initial conditions for reasonable inflation epoch. We derive the conditions under which the Friedmann equation admits positive solutions for the Hubble parameter. Then we study the possibility of the inflaton becoming trapped in a local potential minimum induced by the Gauss-Bonnet term. Finally we demonstrate the results on monomial potential models with a quadratic and a quartic potential and show that the slow-roll approximation becomes imprecise in the quartic case.
format Preprint
id arxiv_https___arxiv_org_abs_2504_01365
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Inflation with Gauss-Bonnet correction: beyond slow-roll
Mudrunka, Kamil
Nakayama, Kazunori
General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
If a coupling between the inflaton and the Gauss-Bonnet term is introduced, many models of inflation that were ruled out by the most recent Planck data can be made viable again. The predictions for the scalar spectral index and tensor-to-scalar ratio are typically computed using the slow-roll approximation. In this paper we instead study the full equations of motion and determine the necessary initial conditions for reasonable inflation epoch. We derive the conditions under which the Friedmann equation admits positive solutions for the Hubble parameter. Then we study the possibility of the inflaton becoming trapped in a local potential minimum induced by the Gauss-Bonnet term. Finally we demonstrate the results on monomial potential models with a quadratic and a quartic potential and show that the slow-roll approximation becomes imprecise in the quartic case.
title Inflation with Gauss-Bonnet correction: beyond slow-roll
topic General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2504.01365