Slow-roll approximations in Einstein–Gauss–Bonnet gravity formulated in terms of e-folding numbers

Abstract

In the Einstein–Gauss–Bonnet (EGB) gravity models, the slow-roll approximation has been extended by taking into account the first-order slow-roll parameter \(\delta _1 =-2\,H^2\,\xi ^\prime /U_0\), which is proportional to the first derivative of the Gauss–Bonnet coupling function \(\xi \) with respect to the e-folding number. These extensions lead to the question of the accuracy of effective potential reconstruction during the generalization of attractors in EGB gravity. We have reconstructed models using the extended slow-roll approximations and compared them with the exact expressions and the standard slow-roll approximation.