Coupled quintessence with a potential from supergravity exhibits sign-changing interaction

TL;DR

This paper demonstrates that current cosmological data strongly support a coupled quintessence model derived from supergravity, which exhibits sign-changing interactions and can cross the phantom divide, aligning with observational preferences.

Contribution

It provides the first observational evidence favoring a sign-changing coupling in supergravity-inspired quintessence models, matching data as well as phenomenological parametrizations.

Findings

Strong evidence for non-zero dark energy-dark matter coupling at over 4σ

Data favor models where the interaction sign changes, crossing the phantom divide

Coupled SUGRA quintessence models are statistically indistinguishable from CPL parametrization

Abstract

Quintessence with a potential motivated by supergravity (SUGRA) exhibits several intriguing features. Depending on its initial conditions, it can behave either as dynamical dark energy or effectively as a cosmological constant. Moreover, when quintessence is coupled to dark matter, the effective dark-energy equation of state can cross the phantom divide. In this paper, we test both coupled and uncoupled SUGRA quintessence models using DESI BAO, DES-Dovekie SNIa, and Planck CMB data. We find that current observations strongly favor a coupling between dark energy and dark matter, with the coupling parameter deviating from zero at more than $4\sigma$. The data also favor the branch of coupled SUGRA quintessence in which the energy transfer between the two dark sectors changes sign, leading to a crossing of the phantom divide by the effective dark-energy equation of state. Interestingly, this coupled SUGRA branch is statistically indistinguishable from dark energy described by the CPL parametrization, with only a very small difference in $\chi^2_\mathrm{min}$. Our results suggest that coupled quintessence with a SUGRA potential provides a field-theoretic realization of the evolving dark energy behavior favored by the latest observations.