Testing the Anton-Schmidt dark energy model with the DESI DR2 measurements

Abstract

We present a comparative cosmological analysis of the Anton-Schmidt, $Λ$CDM, and CPL models using baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument Data Release 2, combined with the Planck PR4 (NPIPE) CamSpec Cosmic Microwave Background likelihoods and three Type Ia supernova catalogues: Pantheon$+$, DES-Dovekie, and Union3. We use Markov Chain Monte Carlo analyses to constrain the parameters of the Anton-Schmidt model against each dataset combination. We find that the Anton-Schmidt model provides a good fit to current cosmological observations. The Anton-Schmidt model provides a good fit to the current cosmological observations but does not provide a significant alleviation of either the $H_0$ or the $S_8$ tensions. The Anton-Schmidt parameter is tightly constrained to $B \simeq -0.38$, indicating that the logarithmic correction becomes relevant only at late times. The Anton-Schmidt and CPL models predict quintessence-like present-day dark-energy equations of state and shows Quintom-B evolution, with their dark-energy equation-of-state parameters crossing the phantom divide at approximately $z \approx 0.5$. The characteristic density scale is constrained to be $ρ_\ast/ρ_{c,0}\sim4\text{--}5$, substantially smaller than the large density scales typically assumed in logotropic-inspired scenarios, indicating that the Anton-Schmidt correction mainly affects the late-time expansion history. Finally, Bayesian evidence shows moderate-to-strong preference for the Anton-Schmidt model over the $Λ$CDM model and strong-to-decisive preference over the CPL parametrization. Although the Anton-Schmidt model does not alleviate the current cosmological tensions, it emerges as a statistically favored dynamical dark-energy scenario whose cosmological implications deserve further tested with forthcoming Stage-IV large-scale structure observations.