Generalization of cosmological attractor approach to Einstein–Gauss–Bonnet gravity

Abstract

We construct models with the Gauss–Bonnet term multiplied by a function of the scalar field leading to an inflationary scenario. The consideration is related to the slow-roll approximation. The cosmological attractor approach gives the spectral index of scalar perturbations which is in a good agreement with modern observation and allows for variability of the tensor-to-scalar ratio. We reconstruct models with variability of parameters, which allows one to reproduce cosmological attractor predictions for inflationary parameters in an approximation of the leading order of 1/N in Einstein–Gauss–Bonnet gravity.

De Sitter Solutions in Einstein–Gauss–Bonnet Gravity

“…The cosmological models with the Gauss-Bonnet term are motivated by the string theory [30][31][32][33][34][35][36][37] and are actively used for describing of both the early Universe evolution (inflation) [25][26][27][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] and the current dark energy dominated epoch [28][29][30][31]36,37,[58][59][60][61][62][63][64][65][66]. Note that both stages of the Universe evolution are characterized by the quasi de Sitter accelerated expansion of the Universe.…”

Gauss–Bonnet term corrections in scalar field cosmology

“…Cosmological models with the Gauss-Bonnet (GB) term in four-dimensional Friedmann universe was considered earlier in a large number of works (for example, see [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]). The important property of such a models is that the GBterm affects the cosmological dynamics in four-dimensional space-time only for the case of non-minimal coupling of this term with a scalar field [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] that can be defined by some coupling function ξ(φ).…”

On the coupling of vector fields to the Gauss-Bonnet invariant

“…In this paper, we examine a cosmological vector field non-minimally coupled to gravity through the Gauss-Bonnet invariant. Although couplings between the Gauss-Bonnet invariant and scalar fields have been explored in the context of inflationary cosmology (Tsujikawa, Sami, & Maartens, 2004;Carter & Neupane, 2006.;Satoh & Soda, 2008;Guo & Schwarz, 2009;Sadeghi, Setare, & Banijamali, 2009;Guo & Schwarz, 2010;Satoh, 2010;Jiang, Hu, & Guo, 2013;Nozari & Rashidi, 2013;Koh, Lee, Lee, & Tumurtushaa, 2014;Okada & Okada, 2016;Kanti, Gannouji, & Dadhich, 2015;van de Bruck, Dimopoulos, & Longden, 2016;Koh, Lee, & Tumurtushaa, 2017;Mathew & Shankaranarayanan, 2016;van de Bruck, Dimopoulos, Longden, & Owen, 2017;Fomin & Chervon, 2017;Yi, Gong, & Sabir, 2018;Granda & Jimenez, 2019b, 2019aJimenez, Granda, & Elizalde, 2019;Kleidis & Oikonomou, 2019;Fomin, 2020;Pozdeeva, 2020;Rashidi & Nozari, 2020), the coupling with a massive vector field has not been sufficiently explored in the literature (Oliveros, 2017). Non-minimal couplings of the electromagnetic field to gravity, in particular to the Gauss-Bonnet invariant, have been considered as a mechanism to generate large-scale magnetic fields during inflation (Sadeghi et al, 2009;Bamba & Odintsov, 2008).…”