Running Hubble constant: evolutionary Dark Energy

TL;DR

This paper proposes an evolutionary dark energy model with bulk viscosity effects, analyzing supernova data to suggest a running Hubble constant with redshift, which may better fit observations than the standard $\\Lambda$CDM model.

Contribution

It introduces a dark energy model incorporating non-equilibrium effects and bulk viscosity, and demonstrates its potential to explain a variable Hubble constant using supernova data.

Findings

The model fits supernova data better than $\\Lambda$CDM.

Evidence suggests the Hubble constant varies with redshift.

The evolutionary dark energy model provides a more accurate description of the data.

Abstract

We discuss an evolutionary dark energy model, based on the presence of non-equilibrium effects on the dark energy constituents, which are described via a bulk viscosity contribution. We implement the proposed dynamics by the analysis of the 40-bins Type Ia Supernovae (SNe) Pantheon sample data, in order to outline the existence of a running Hubble constant with the redshift. Via a fitting procedure, we determine the value of the additional parameter that our model possesses with respect a standard $\Lambda$ Cold Dark Matter ($\Lambda$CDM) scenario. As important result, the evolutionary dark energy proposal seems more appropriate to describe the binned SN analysis with respect to the $\Lambda$CDM Hubble parameter, i.e. a non running value for the Hubble constant over the bins.