Exact solutions in a scalar-tensor model of dark energy

TL;DR

This paper derives exact solutions in a scalar-tensor dark energy model with non-minimal couplings, revealing transitions from matter dominance to late-time accelerated expansion and analyzing their stability.

Contribution

It introduces a method to obtain exact solutions in a scalar-tensor dark energy model with specific couplings, unifying early and late universe behaviors.

Findings

Exact solutions connecting matter dominance to dark energy phases

Restrictions on couplings simplify the equations

Stability analysis of solutions without matter

Abstract

We consider a model of scalar field with non minimal kinetic and Gauss Bonnet couplings as a source of dark energy. Based on asymptotic limits of the generalized Friedmann equation, we impose restrictions on the kinetic an Gauss-Bonnet couplings. This restrictions considerable simplify the equations, allowing for exact solutions unifying early time matter dominance with transitions to late time quintessence and phantom phases. The stability of the solutions in absence of matter has been studied.