Robustness of dark energy phenomenology across different parameterizations

TL;DR

This study investigates how different dark energy parameterizations affect the interpretation of cosmological data, finding that conclusions about certain dark energy models remain consistent across various parameterizations.

Contribution

It demonstrates that the viability of specific dark energy models is robust against the choice of common two-parameter parameterizations.

Findings

Dark energy model viability is independent of parameterization.

All tested parameterizations can accurately represent the models.

Results support the robustness of dark energy phenomenology across parameterizations.

Abstract

The recent evidence for dynamical dark energy from DESI, in combination with other cosmological data, has generated significant interest in understanding the nature of dark energy and its underlying microphysics. However, interpreting these results critically depends on how dark energy is parameterized. This paper examines the robustness of conclusions about the viability of particular kinds of dynamical dark energy models to the choice of parameterization, focusing on four popular two-parameter models: the Chevallier-Polarski-Linder (CPL), Jassal-Bagla-Padmanabhan (JBP), Barboza-Alcaniz (BA), and exponential (EXP) parameterizations. We find that conclusions regarding the viability of minimally and non-minimally coupled quintessence models are independent of the parameterization adopted. We demonstrate this both by mapping these dark energy models into the $(w_0, w_a)$ parameter space defined by these various parameterizations and by showing that all of these parameterizations can equivalently account for the phenomenology predicted by these dark energy models to a high degree of accuracy.