Compatibility of Einstein-Gauss-Bonnet Inflation Theory with Non-Minimal Derivative Coupling in the constant-roll
Naufal Aulia Adam (a*), Getbogi Hikmawan (a), Freddy Permana Zen (a, b)

a) Theoretical Physics Division, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132, Indonesia
* naufal.auliadam[at]gmail.com
b) Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10 Bandung 40132, Indonesia

Abstract

Inflation is a theory in cosmology that explains that the early universe experienced a very fast expansion in a very short time and is able to explain some cosmological problems and the presence of gravitational waves generated during the inflation period. Based on the event GW170817, it was found that \(c_t^2=1\), which indicates that the speed of gravitational waves is nearly equal as the speed of light. This contradicts several modified theories of gravity, one of which is the Einstein-Gauss-Bonnet theory. This paper examines the compatibility of Einstein-Gauss-Bonnet inflation theory with the GW170817 phenomenon, with the addition of the Non-minimal derivative coupling term and the constant-roll approach and its characteristics. The formulation of observational quantities is carried out using Horndeski theory and Effective Field Theory with ADM formalism and the calculations are done numerically. The constant values are selected in such a way that the spectral index values and tensor-scalar ratios are close to the 2018 Planck data. The results found that this theory is compatible with GW170817 with the influence of Gauss-Bonnet term and constant-roll parameter \(\beta\) most dominant.

Keywords: Inflation- Gravitational Waves- Einstein-Gauss-Bonnet

Topic: Theoretical High Energy Physics