No evidence for dynamical dark energy in two models

TL;DR

This study tests for evolving dark energy using two null models and various cosmological data, finding no significant evidence for dynamical dark energy and noting slight alleviation of H0 and sigma8 tensions.

Contribution

The paper introduces two null tests for dynamical dark energy and applies them to multiple datasets, providing constraints that support a non-evolving dark energy model.

Findings

No evidence of dynamical dark energy at 1.2σ confidence level.

Both models slightly reduce H0 tension.

Both models slightly reduce sigma8 tension.

Abstract

To investigate whether the dark energy evolves over time, we propose two null tests and constrain them using the data combination of cosmic microwave background radiation, baryonic acoustic oscillations, Type Ia supernovae, Planck-2015 lensing and cosmic chronometers. We find that, for these two models, there is no evidence of the dynamical dark energy at the $1.2\sigma$ confidence level. Interestingly, both models could slightly alleviate (i) the current Hubble constant ($H_0$) tension between the global fitting derivation by the Planck collaboration and the local observation by Riess {\it et al.}; (ii) the root-mean-square density fluctuations ($\sigma_8$) tension between the Planck-2015 data and several low-redshift large scale structure probes.