Beyond $f(ϕ)\mathcal{G}$: Gauss--Bonnet inflation with $μ(ϕ,X)$

Fuente: arXiv
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Main Authors: Seidabadi, Ali, Saghafi, Sara, Nozari, Kourosh
Format: Preprint
Published: 2026
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author Seidabadi, Ali
Saghafi, Sara
Nozari, Kourosh
author_facet Seidabadi, Ali
Saghafi, Sara
Nozari, Kourosh
contents Gauss--Bonnet inflation typically affects the dynamics over an extended portion of the trajectory, making it difficult to isolate a controlled imprint at CMB scales. We consider a trajectory-selective coupling \(μ(ϕ,X)\) that gates the Gauss--Bonnet sector in phase space, enabling the higher-curvature contribution to be localized within a finite e-fold window while remaining negligible elsewhere. We identify stable inflationary solutions consistent with this localization and enforce standard ghost and gradient stability conditions for both scalar and tensor perturbations. For these viable backgrounds we compute pivot-scale observables and examine their dependence on the overall Gauss--Bonnet strength and on the kinetic gating. The framework offers a controlled route for realizing localized higher-curvature effects with predictable consequences for CMB-scale measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2604_03828
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Beyond $f(ϕ)\mathcal{G}$: Gauss--Bonnet inflation with $μ(ϕ,X)$
Seidabadi, Ali
Saghafi, Sara
Nozari, Kourosh
Cosmology and Nongalactic Astrophysics
Gauss--Bonnet inflation typically affects the dynamics over an extended portion of the trajectory, making it difficult to isolate a controlled imprint at CMB scales. We consider a trajectory-selective coupling \(μ(ϕ,X)\) that gates the Gauss--Bonnet sector in phase space, enabling the higher-curvature contribution to be localized within a finite e-fold window while remaining negligible elsewhere. We identify stable inflationary solutions consistent with this localization and enforce standard ghost and gradient stability conditions for both scalar and tensor perturbations. For these viable backgrounds we compute pivot-scale observables and examine their dependence on the overall Gauss--Bonnet strength and on the kinetic gating. The framework offers a controlled route for realizing localized higher-curvature effects with predictable consequences for CMB-scale measurements.
title Beyond $f(ϕ)\mathcal{G}$: Gauss--Bonnet inflation with $μ(ϕ,X)$
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2604.03828