Cosmological Evolution of a Tachyon-Quintom Model of Dark Energy

TL;DR

This paper investigates a dark energy model with two scalar fields, tachyon and phantom tachyon, demonstrating its ability to evolve the equation of state across the cosmological constant boundary and analyzing its stability and solutions.

Contribution

It introduces a novel two-field tachyon-quintom model with inverse square potentials and explores its phase-space stability and cosmological evolution, including interactions between fields.

Findings

Existence of a unique stable critical point with power-law solutions.

The model allows the equation of state to cross from above to below -1.

Interaction between fields influences the stability and evolution.

Abstract

In this work we study the cosmological evolution of a dark energy model with two scalar fields, i.e. the tachyon and the phantom tachyon. This model enables the equation of state $w$ to change from $w>-1$ to $w<-1$ in the evolution of the universe. The phase-space analysis for such a system with inverse square potentials shows that there exists a unique stable critical point, which has power-law solutions. In this paper, we also study another form of tachyon-quintom model with two fields, which voluntarily involves the interactions between both fields.