Model-Independent Reconstruction of Quintessence Potential and Kinetic Energy from DESI DR2 and Pantheon+ Supernovae

TL;DR

This paper reconstructs the quintessence dark energy dynamics directly from recent cosmological data using non-parametric methods, revealing a decreasing potential and a kinetic energy crossing zero near the matter-dark energy equality epoch.

Contribution

It introduces a model-independent, non-parametric reconstruction of quintessence potential and kinetic energy from DESI DR2 and Pantheon+ data, avoiding theoretical priors.

Findings

Potential decreases monotonically with redshift, consistent with thawing quintessence.

Kinetic energy crosses zero near redshift 1, the dark energy-matter equality epoch.

Apparent negative kinetic energy at intermediate redshifts is a statistical artifact, not new physics.

Abstract

We present a model-independent reconstruction of the quintessence scalar field's dynamics-both its potential and kinetic energy-directly from the latest cosmological observations. Our analysis combines DESI DR2 baryon acoustic oscillation measurements with the Pantheon plus Type Ia supernova compilation, employing Gaussian process with four distinct covariance kernels to avoid theoretical priors on the potential's functional form. Key findings reveal a monotonically decreasing potential with redshift, consistent with thawing quintessence, and a kinetic energy that crosses zero near $z\sim 1$, marking the dark energy-matter equality epoch. Notably, while apparent negative kinetic energy values emerge at intermediate redshifts (0.5<z<1.0), these are statistical artifacts within uncertainties, arising from error amplification in derivative reconstruction rather than new physics. Our results demonstrate the power of non-parametric methods to constrain dynamical dark energy and show minimal dependence on the choice of cosmological priors, whether from local (SH0ES) or early-universe (Planck) measurements.