Non-minimally coupled quintessence with sign-switching interaction

TL;DR

This paper introduces a non-minimally coupled quintessence model that explains late-time dark energy dynamics and sign-changing energy transfer, aligning well with recent cosmological observations.

Contribution

The paper presents a novel non-minimally coupled quintessence framework with sign-changing interaction, explaining late-time dark energy behavior and observational data.

Findings

Model favors current cosmological data over ΛCDM and w0waCDM.

Dark energy density decreases when it dominates the universe.

Effective crossing behavior in dark energy sector inferred from data.

Abstract

We propose a new non-minimally coupled quintessence model to account for the late-time dark energy dynamics indicated by recent DESI measurements. Within this framework, the quintessence density begins to decrease only when it starts to dominate the universe, which naturally accounts for the late-time onset of dark energy weakening. The coupling also induces a sign change in the effective energy transfer between dark matter and dark energy during cosmic evolution. While the scalar field itself remains canonical and never crosses the phantom divide, the modified evolution of the dark matter density gives rise to an effective crossing behavior in the observationally inferred dark energy sector. Compared with both $\Lambda$CDM and $w_0w_a$CDM models, our model is favored more strongly by current cosmological data. This work may provide a promising avenue for understanding the observational late-time weakening of dark energy and the origin of its dynamics.