On the evidence of dynamical dark energy

TL;DR

This paper evaluates how robust the DESI BAO data is in indicating dynamical dark energy, finding that conclusions depend on the chosen cosmological model and that data constraints are relatively insensitive to spatial curvature.

Contribution

It assesses the model dependence of dynamical dark energy evidence from DESI BAO data, highlighting the influence of different models and spatial curvature on the results.

Findings

DESI BAO data slightly tightens parameter constraints.

Tension between models varies with the chosen dark energy parametrization.

Spatial curvature has minimal impact on the results.

Abstract

To elucidate the robustness of the baryon acoustic oscillation (BAO) data measured by the Dark Energy Spectroscopic Instrument (DESI) in capturing the dynamical behavior of dark energy, we assess the model dependence of the evidence for dynamical dark energy inferred from the DESI BAO data. While the DESI BAO data slightly tightens the constraints on model parameters and increases the tension between the Chevallier-Polarski-Linder (CPL) model and the $\Lambda$CDM model, we find that the influence of DESI BAO data on the constraint of $w_0$ is small in the SSLCPL model. In comparison to the CPL model, the tension with the $\Lambda$CDM model is reduced for the SSLCPL model, suggesting that the evidence for dynamical dark energy from DESI BAO data is dependent on cosmological models. The inclusion of spatial curvature has little impact on the results in the SSLCPL model.