Dark Energy as a Critical Phenomenon: a Resolution for Hubble Tension

TL;DR

This paper introduces a critical phenomena-inspired dark energy model, CEDE, which explains the Hubble tension by proposing dark energy emergence at a transition redshift, aligning with both CMB and local Hubble measurements.

Contribution

The paper presents the critically emergent dark energy (CEDE) model, linking dark energy to critical phenomena and providing a new explanation for the Hubble tension.

Findings

CEDE supports a non-trivial transition at redshift z_c.

The model favors larger Hubble constant values consistent with local measurements.

CEDE naturally explains the Hubble tension through dark energy substructure.

Abstract

We propose a dark energy model based on the physics of critical phenomena which is consistent with both the Planck's CMB and the Riess et al.'s local Hubble measurements. In this model the dark energy density behaves like the magnetization of the Ising model. This means the dark energy is an emergent phenomenon and we named it critically emergent dark energy model, CEDE. In CEDE, dark energy emerges at a transition redshift, $z_c$, corresponding to the critical temperature in critical phenomena. Combining the Planck CMB data and local measurement of the Hubble constant from Riess et al. (2019) we find statistically significant support for this transition with respect to the case of very early transition that represents effectively the cosmological constant. This is understandable since CEDE model naturally prefers larger values of Hubble constant consistent with local measurements. Since CEDE prefers a non-trivial transition when we consider both high redshift Planck CMB data and local Hubble constant measurements, we conclude that $H_0$ tension can be a hint for the substructure of the dark energy as a well-studied properties of critical phenomena.