Dynamics of a two scalar field cosmological model with phantom terms

TL;DR

This paper analyzes the complex dynamics of a two-scalar-field cosmological model with phantom terms, revealing how the universe's evolution can cross the phantom divide twice without instabilities, and assesses the models' viability.

Contribution

It provides a detailed dynamical analysis of four scalar field cosmological models with phantom components, highlighting novel behaviors like multiple phantom divide crossings without ghosts.

Findings

The cosmological fluid can cross the phantom divide twice without ghosts.

Phantom scalar fields can lead to viable cosmological evolutions.

The models' asymptotic behaviors are characterized in flat FRW space.

Abstract

We perform a detailed analysis on the dynamics of a Chiral-like cosmological model where the scalar fields can have negative kinetic terms. In particular, we study the asymptotic dynamics for the gravitational field equations for four different models in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker background space. When one of the scalar fields is phantom, we calculated that the cosmological fluid can evolves such that the parameter for the equation of state crosses twice the phantom divide line without the appearance of ghosts. Moreover, the cosmological viability of these four models is discussed.