Red or Blue Tensor Spectrum from GW170817-compatible Einstein-Gauss-Bonnet Theory: A Detailed Analysis

Fuente: arXiv
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Auteurs principaux: Oikonomou, V. K., Tsyba, Pyotr, Razina, Olga
Format: Preprint
Publié: 2024
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author Oikonomou, V. K.
Tsyba, Pyotr
Razina, Olga
author_facet Oikonomou, V. K.
Tsyba, Pyotr
Razina, Olga
contents In this work we shall prove that the tensor spectral index of the primordial tensor perturbations for GW170817-compatible Einstein-Gauss-Bonnet theories, takes the approximate simplified form $n_{\mathcal{T}}\simeq 2\left(-1+\frac{1}{λ(ϕ)} \right)ε_1$ at leading order, with $λ(ϕ)$ being a function of the scalar field which depends on the scalar field potential and the second derivative of the scalar-Gauss-Bonnet coupling $ξ''(ϕ)$. With our analysis we aim to provide a definitive criterion for selecting Einstein-Gauss-Bonnet models that can provide a blue-tilted inflationary phenomenology, by simply looking at the scalar potential and the scalar-Gauss-Bonnet coupling. We shall prove this using two distinct approaches and as we show the tilt of the tensor spectral index is determined by the values of the potential $V(ϕ)$ and of scalar-Gauss-Bonnet coupling at first horizon crossing. Specifically the blue-tilted tensor spectral index can occur when $ξ''(ϕ_*)V(ϕ_*)>0$ at first horizon crossing.
format Preprint
id arxiv_https___arxiv_org_abs_2402_02049
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Red or Blue Tensor Spectrum from GW170817-compatible Einstein-Gauss-Bonnet Theory: A Detailed Analysis
Oikonomou, V. K.
Tsyba, Pyotr
Razina, Olga
General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
In this work we shall prove that the tensor spectral index of the primordial tensor perturbations for GW170817-compatible Einstein-Gauss-Bonnet theories, takes the approximate simplified form $n_{\mathcal{T}}\simeq 2\left(-1+\frac{1}{λ(ϕ)} \right)ε_1$ at leading order, with $λ(ϕ)$ being a function of the scalar field which depends on the scalar field potential and the second derivative of the scalar-Gauss-Bonnet coupling $ξ''(ϕ)$. With our analysis we aim to provide a definitive criterion for selecting Einstein-Gauss-Bonnet models that can provide a blue-tilted inflationary phenomenology, by simply looking at the scalar potential and the scalar-Gauss-Bonnet coupling. We shall prove this using two distinct approaches and as we show the tilt of the tensor spectral index is determined by the values of the potential $V(ϕ)$ and of scalar-Gauss-Bonnet coupling at first horizon crossing. Specifically the blue-tilted tensor spectral index can occur when $ξ''(ϕ_*)V(ϕ_*)>0$ at first horizon crossing.
title Red or Blue Tensor Spectrum from GW170817-compatible Einstein-Gauss-Bonnet Theory: A Detailed Analysis
topic General Relativity and Quantum Cosmology
Cosmology and Nongalactic Astrophysics
High Energy Physics - Theory
url https://arxiv.org/abs/2402.02049