Quintom fields from chiral K-essence cosmology

TL;DR

This paper explores a chiral K-essence cosmological model with quintom fields, providing analytical solutions for classical and quantum cases, including a big-bounce scenario and quantum probability analysis.

Contribution

It introduces a novel analysis of quintom fields within chiral K-essence cosmology, solving classical and quantum equations analytically with consideration of factor ordering.

Findings

Big-bounce replaces big-bang singularity.

Quantum probability density damped over time.

Phantom line crossing for specific parameters.

Abstract

In this paper, we present an analysis of a chiral cosmological scenario from the perspective of K-essence formalism. In this setup, several scalar fields interact within the kinetic and potential sectors. However, we only consider a flat Friedmann--Robertson--Lama\^{\i}tre--Walker universe coupled minimally to two quintom fields: one quintessence and one phantom. We examine a classical cosmological framework, where analytical solutions are obtained. Indeed, we present an explanation of the ``big-bang'' singularity by means of a ``big-bounce''. Moreover, having a barotropic fluid description and for a particular set of parameters, the phantom line is in fact crossed. Additionally, for the quantum counterpart, the Wheeler--DeWitt equation is analytically solved for various instances, where the factor-ordering problem has been taken into account (measured by the factor Q). Hence, this approach allows us to compute the probability density of the previous two classical subcases. It turns out that its behavior is in effect damped as the scale factor and the scalar fields evolve. It also tends towards the phantom sector when the factor ordering constant $\rm Q\ll 0$.