Evidence for dynamical dark energy from DESI-DR2 and SN data? A symbolic regression analysis

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Main Authors: Sousa-Neto, Agripino, Bengaly, Carlos, Gonzalez, Javier E., Alcaniz, Jailson
Format: Preprint
Published: 2025
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author Sousa-Neto, Agripino
Bengaly, Carlos
Gonzalez, Javier E.
Alcaniz, Jailson
author_facet Sousa-Neto, Agripino
Bengaly, Carlos
Gonzalez, Javier E.
Alcaniz, Jailson
contents Recent measurements of Baryon Acoustic Oscillations (BAO) from the Dark Energy Spectroscopic Survey (DESI DR2), combined with data from the cosmic microwave background (CMB) and Type Ia supernovae (SNe), challenge the $Λ$-Cold Dark Matter ($Λ$CDM) paradigm. They indicate a potential evolution in the dark energy equation of state (EoS), $w(z)$, as suggested by analyses that employ parametric models. In this paper, we use a model-independent approach known as high performance symbolic regression (PySR) to reconstruct $w(z)$ directly from observational data, allowing us to bypass prior assumptions about the underlying cosmological model. Our findings confirm that the DESI DR2 data alone agree with the $Λ$CDM model ($w(z) = -1$) at the redshift range considered. Additionally, when combining DESI data with existing compilations of SN distance measurements, such as Patheon+ and DESY5, we observe no deviation from the $Λ$CDM model within $3σ$ (C.L.) for the interval of values of present-day matter density parameter $Ω_m$ and the sound horizon at the drag epoch $r_d$ currently constrained by observational data. Therefore, similarly to the DESI DR1 case, these results suggest that it is still premature to claim statistically significant evidence for a dynamical EoS or deviations from the $Λ$CDM model based on the current DESI data in combination with supernova measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2502_10506
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evidence for dynamical dark energy from DESI-DR2 and SN data? A symbolic regression analysis
Sousa-Neto, Agripino
Bengaly, Carlos
Gonzalez, Javier E.
Alcaniz, Jailson
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
Recent measurements of Baryon Acoustic Oscillations (BAO) from the Dark Energy Spectroscopic Survey (DESI DR2), combined with data from the cosmic microwave background (CMB) and Type Ia supernovae (SNe), challenge the $Λ$-Cold Dark Matter ($Λ$CDM) paradigm. They indicate a potential evolution in the dark energy equation of state (EoS), $w(z)$, as suggested by analyses that employ parametric models. In this paper, we use a model-independent approach known as high performance symbolic regression (PySR) to reconstruct $w(z)$ directly from observational data, allowing us to bypass prior assumptions about the underlying cosmological model. Our findings confirm that the DESI DR2 data alone agree with the $Λ$CDM model ($w(z) = -1$) at the redshift range considered. Additionally, when combining DESI data with existing compilations of SN distance measurements, such as Patheon+ and DESY5, we observe no deviation from the $Λ$CDM model within $3σ$ (C.L.) for the interval of values of present-day matter density parameter $Ω_m$ and the sound horizon at the drag epoch $r_d$ currently constrained by observational data. Therefore, similarly to the DESI DR1 case, these results suggest that it is still premature to claim statistically significant evidence for a dynamical EoS or deviations from the $Λ$CDM model based on the current DESI data in combination with supernova measurements.
title Evidence for dynamical dark energy from DESI-DR2 and SN data? A symbolic regression analysis
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2502.10506