Phase space analysis for a scalar-tensor model with kinetic and Gauss-Bonnet couplings

TL;DR

This paper analyzes the phase space of a string-inspired scalar-tensor dark energy model with exponential couplings, revealing various cosmological evolutions including late-time acceleration.

Contribution

It introduces a phase space analysis for a scalar-tensor model with kinetic and Gauss-Bonnet couplings, highlighting new stable late-time solutions.

Findings

Identified critical points representing different cosmological eras.

Found trajectories leading to stable dark energy dominated universe.

Demonstrated the model's capability to describe late-time acceleration.

Abstract

We study the phase space for an scalar-tensor string inspired model of dark energy with non minimal kinetic and Gauss Bonnet couplings. The form of the scalar potential and of the coupling terms is of the exponential type, which give rise to appealing cosmological solutions. The critical points describe a variety of cosmological scenarios that go from matter or radiation dominated universe to dark energy dominated universe. There were found trajectories in the phase space departing from unstable or saddle fixed points and arriving to the stable scalar field dominated point corresponding to late-time accelerated expansion.