Global dynamics of the hyperbolic Chiral-Phantom model

TL;DR

This paper analyzes the global behavior of a multifield cosmological model with phantom scalar fields, revealing how the Hubble function can change sign and how the evolution differs from standard hyperbolic theories, including perturbation analysis.

Contribution

It provides a detailed analysis of the asymptotic dynamics of the Chiral-Phantom model with mixed kinetic terms and phantom properties, including global evolution and perturbations.

Findings

Hubble function can change sign in the model

The quintessence limit is recovered in the evolution

Cosmological evolution differs from standard hyperbolic theory

Abstract

We perform a detailed analysis of the asymptotic behavior of a multifield cosmological model with phantom terms. Specifically, we consider the Chiral-Phantom model consisting of two scalar fields with a mixed kinetic term, while one scalar field has negative kinetic energy, that is, it has phantom properties. We show that the Hubble function can change sign, and we study the global evolution of the field equation in the finite and infinity regions with the use of Poincar\'{e} variables. We find that in the Chiral-Phantom model the limit of the quintessence scalar field is recovered while the cosmological evolution differs from the standard hyperbolic theory. Finally, the linear cosmological perturbations are studied.