Speed of sound and scalar spectral index: Reconstructing inflation and reheating in a non-canonical theory

Fuente: arXiv
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Main Authors: Herrera, Ramon, Rios, Carlos
Format: Preprint
Published: 2024
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author Herrera, Ramon
Rios, Carlos
author_facet Herrera, Ramon
Rios, Carlos
contents In this article we analyze the reconstruction of inflation in the framework of a non-canonical theory. In this sense, we study the viability of reconstructing the background variables assuming a non-lineal kinetic term given by $K(X,ϕ)=X+g(ϕ)X^2$, with $X$ the standard kinetic term associated to the scalar field $ϕ$ and $g(ϕ)$ an arbitrary coupling function. In order to achieve this reconstruction in the context of inflation, we assume the slow-roll approximation together with the parametrization of the scalar spectral index $n_s$ and the speed of sound $c_s$ as a function of the number of $e-$folds $N$. By assuming the simplest parametrizations for $n_s-1=-2/N$ and $c_s\propto N^{-β}$ with $β$ a constant, we find the reconstruction of the effective potential $V(ϕ)$ and the coupling function $g(ϕ)$ in terms of the scalar field. Besides, we study the reheating epoch by considering a constant equation of state parameter, where we determine the temperature and number of $e-$folds during the reheating epoch in terms of the reconstructed variables and the observational parameters. In this way, the parameter-space related to the reconstructed inflationary model are constrained during the epochs of inflation and reheating by assuming the current astronomical data from Planck and BICEP/Keck results.
format Preprint
id arxiv_https___arxiv_org_abs_2401_10312
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Speed of sound and scalar spectral index: Reconstructing inflation and reheating in a non-canonical theory
Herrera, Ramon
Rios, Carlos
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
In this article we analyze the reconstruction of inflation in the framework of a non-canonical theory. In this sense, we study the viability of reconstructing the background variables assuming a non-lineal kinetic term given by $K(X,ϕ)=X+g(ϕ)X^2$, with $X$ the standard kinetic term associated to the scalar field $ϕ$ and $g(ϕ)$ an arbitrary coupling function. In order to achieve this reconstruction in the context of inflation, we assume the slow-roll approximation together with the parametrization of the scalar spectral index $n_s$ and the speed of sound $c_s$ as a function of the number of $e-$folds $N$. By assuming the simplest parametrizations for $n_s-1=-2/N$ and $c_s\propto N^{-β}$ with $β$ a constant, we find the reconstruction of the effective potential $V(ϕ)$ and the coupling function $g(ϕ)$ in terms of the scalar field. Besides, we study the reheating epoch by considering a constant equation of state parameter, where we determine the temperature and number of $e-$folds during the reheating epoch in terms of the reconstructed variables and the observational parameters. In this way, the parameter-space related to the reconstructed inflationary model are constrained during the epochs of inflation and reheating by assuming the current astronomical data from Planck and BICEP/Keck results.
title Speed of sound and scalar spectral index: Reconstructing inflation and reheating in a non-canonical theory
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2401.10312