Tracker phantom field and a cosmological constant: dynamics of a composite dark energy model

TL;DR

This paper investigates a combined dark energy model with phantom fields and a cosmological constant, analyzing their dynamics and observational constraints, revealing a preference for phantom energy but leaving the nature of the cosmological constant uncertain.

Contribution

It introduces a comprehensive analysis of tracker phantom dark energy models with general scalar potentials, considering their interplay with the cosmological constant and observational data.

Findings

Phantom dark energy increases the Hubble parameter.

Bayesian analysis favors phantom fields over positive cosmological constant.

Negative cosmological constant remains a plausible dark sector component.

Abstract

In this work, we study tracker phantom dark energy models with a general parameterization of the scalar potentials. Our analysis also considers the scenario of having both phantom field and the cosmological constant as the dark energy components. A detailed statistical analysis with current cosmological observations shows an increase in the value of the Hubble parameter due to the presence of phantom dark energy but it can not alleviate the Hubble tension completely. Our results using Bayesian methods suggests a decisive evidence in favor of a phantom field over a positive cosmological constant, although the possibility of a negative cosmological constant cannot be ruled out hidden in the dark sector.