Tachyon Cosmology with Gauss–Bonnet and Non-Minimal Kinetic Couplings

Abstract

We consider a tachyonic model of dark energy in which scalar field non-minimally coupled with curvature and kinetic part of its Lagrangian density. Additionally the model contains the Gauss–Bonnet coupling to the scalar field through an arbitrary function. The non-minimal Gauss–Bonnet coupling function and scalar field potential have been obtained for power-law solution and then for a dynamically varying equation of state. We have extracted the required condition for the so-called phantom divide line crossing in the model and represented such a crossing numerically.