Non-minimally Coupled Running Curvaton for DESI-preferred Dynamical Dark Energy and Hubble Tension

TL;DR

This paper introduces a non-minimally coupled running curvaton model that aligns with DESI 2025 dark energy observations and may help address the Hubble tension.

Contribution

It extends the running curvaton scenario with a non-minimal gravitational coupling, maintaining early-universe predictions and providing a viable dark energy framework.

Findings

The model can produce late-time equations of state in the DESI-preferred region.

It preserves early-universe predictions via parameter redefinition.

A benchmark solution shifts the inferred Hubble constant upward.

Abstract

Recent DESI 2025 results have renewed interest in dynamical dark energy models with phantom crossing. In this work, we extend the running curvaton scenario by introducing a non-minimal gravitational coupling, $\xi \chi^2 R$. We show that this coupling can drive the late-time equation of state into the DESI-preferred region in the $(w_0,w_a)$ plane. We further find that, at leading order, the early-universe predictions of the original running curvaton model can be preserved through a parameter redefinition, while the scalar sector remains free of gradient instability in the regime considered. A parameter scan identifies viable regions and a benchmark solution that also shifts the background-inferred value of $H_0$ upward. These results suggest that the non-minimally coupled running curvaton provides a viable framework for DESI-motivated dark energy evolution, with possible implications for the Hubble tension.