Einstein–Gauss–Bonnet inflation and its consistency with ACT observations
Document Type
Article
Publication Date
6-2026
Abstract
We investigate inflationary dynamics in Einstein–Gauss–Bonnet gravity, focusing on the interplay between the standard Hubble slow–roll parameters and the additional flow parameters induced by a scalar–dependent Gauss–Bonnet coupling. We demonstrate that a prolonged slow–roll inflationary phase free from ghost and gradient instabilities with a natural exit can be realized. As a result, we show that the present model can be consistent with the constraints on the spectral index of the scalar perturbations along with the upper limit placed on the tensor-to-scalar ratio reported by the Atacama Cosmology Telescope (ACT) observations due to the effect of the higher-order curvature.
Recommended Citation
Nashed, Gamal and Bamba, Kazuharu, "Einstein–Gauss–Bonnet inflation and its consistency with ACT observations" (2026). Centre for Theoretical Physics and Computations. 404.
https://buescholar.bue.edu.eg/centre_theoretical_physics/404