The Hubble Tension resolved by the DESI Baryon Acoustic Oscillations Measurements

TL;DR

The paper demonstrates that DESI DR2 BAO measurements, when analyzed with a non-parametric, redshift-binned $w(z)$, indicate evolving dark energy. By deriving $H_0$ from this $w(z)$ via the Friedmann equations, they show $H_0(z)$ decreases with redshift, effectively unifying the local and CMB measurements and resolving the Hubble tension within a dynamical dark-energy framework. The approach is model-independent and robust across datasets and binning schemes, offering a cohesive explanation for both the Hubble tension and deviations from ΛCDM. The results motivate future wide-area surveys to further constrain the high-redshift evolution of dark energy.

Abstract

The $Λ$ cold dark matter ($Λ$CDM) cosmological model provides a good description of a wide range of astrophysical and cosmological observations. However, severe challenges to the phenomenological $Λ$CDM model have emerged recently, including the Hubble constant tension and the significant deviation from the $Λ$CDM model reported by the Dark Energy Spectroscopic Instrument (DESI) collaboration. Despite many explanations for the two challenges have been proposed, the origins of them are still intriguing mysteries. Here, we investigate the DESI Baryon Acoustic Oscillations (BAOs) measurements to interpret the Hubble constant tension. Employing a non-parametric method, we find that the dark energy equation of state $w(z)$ evolves with redshift from DESI BAO data and type Ia supernovae. From the Friedmann equations, the Hubble constant ($H_0$) is derived from $w(z)$ model-independently. We find that the values of $H_0$ show a descending trend as a function of redshift, and can effectively resolve the Hubble constant tension. Our study finds that the two unexpected challenges to the $Λ$CDM model can be understood in one physical framework, e.g., dynamical dark energy.

Figures (6)

• Figure 1: Fitting results of the equation of state $w(z)$ of dark energy with the non-parametric method. Panel (a). The black points represent the best-fit values of $w(z)$ with $1\sigma$ confidence level (red bar) at different redshift bins using the DESI DR2 BAO measurements. The black dashed line represents the standard $\Lambda$CDM model with $w(z)=-1$. The redshift intervals of the bins are shown as the blue bars. A descending trend of $w(z)$ is found. Panel (b). Same as panel (a), but for Pantheon plus SNe Ia sample. The $w(z)$ values from BAO and SNe Ia are consistent within 1$\sigma$ confidence level.
• Figure 2: Fitting results of the equation of state $w(z)$ of dark energy with the non-parametric method using BAO and SNe Ia. Panel (a). The black points represent the best-fit values of $w(z)$ with $1\sigma$ confidence level (red bar) at different redshift bins using the DESI DR2 BAO measurements and Pantheon plus SNe Ia sample. The black dashed line represents the standard $\Lambda$CDM model with $w(z)=-1$. The redshift intervals of the bins are shown in the blue bars. A descending trend of $w(z)$ is found. It crosses $w=-1$, suggesting quintom-like behavior. Panel (b). Same as panel (a), but for the DESI DR2 BAO measurements and DESY5 SNe Ia sample. The $w(z)$ values in panels (a) and (b) are consistent within 1$\sigma$ confidence level.
• Figure 3: Corner plot of $w_i$ from the DESI DR2 BAO + Pantheon plus sample. The panels on the diagonal show the 1D histogram for each parameter obtained by marginalizing over the other parameters. The off-diagonal panels show two-dimensional projections of the posterior probability distributions for each pair of parameters, with contours to indicate $1\sigma-3\sigma$ confidence levels.
• Figure 4: Same as Figure \ref{['F_cor_DESI+Pan']}, but for the DESI DR2 BAO + DESY5 SNe Ia sample.
• Figure 5: The descending trend of the Hubble constant $H_0$ derived from the dark energy equation of state $w(z)$ in Figure \ref{['F_w_DP+DD']}. Panel (a). The green points indicate the maximum a posteriori estimates of $H_0(z)$ with $1 \sigma$ error bars from the DESI DR2 BAO measurements and Pantheon plus SNe Ia sample. The redshift of the green points correspond to the midpoint of each redshift bin. The blue solid line and blue band show the $H_0$ value and $1\sigma$ confidence level measured from the local distance ladder Riess2022. The orange solid line and orange band represent the $H_0$ value and $1\sigma$ confidence level derived from the CMB data Planck_2020. The $H_0$ value agrees with that measured from the local distance ladder in $1\sigma$ confidence level at low redshift, and it gradually drops to the value measured from the Planck CMB at high redshift. The Hubble tension is effectively resolved by DESI DR2 BAO measurements. Panel (b). Same as panel (a), but for the DESI DR2 BAO measurements and DESY5 SNe Ia sample. The $H_0$ values in panels (a) and (b) are consistent within 1$\sigma$ confidence level.