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Can Late Dark Energy Transitions Raise the Hubble constant?

Giampaolo Benevento, Wayne Hu, Marco Raveri

TL;DR

The paper investigates whether a late-time dark energy transition near the present epoch ($z<0.1$) can reconcile the Hubble tension by lifting the local $H_0$ value without spoiling high-$z$ observables. It introduces a parameterized LDE model with $(\delta, z_t, \Delta z)$ and computes cosmological observables using EFTCAMB, fitting Planck, BAO, and Pantheon data. Two treatments of SH0ES data are tested: a direct $H_0$ constraint and a calibration of Pantheon SN absolute magnitude $M$, revealing that the former can raise $H_0$ to about 74 but does not address the underlying SN calibration issue, while the latter yields only a modest $H_0$ increase and requires an inconsistent $M$-shift. The study concludes that late-time transitions partly relieve but do not fully resolve the Hubble tension, and emphasizes a calibration-based test as essential for evaluating any dynamical dark energy with localized features.

Abstract

Late times dark energy transitions at redshifts $z \ll 0.1$ can raise the predicted value of the Hubble constant to the SH0ES value, $74.03\pm 1.42$ (km s$^{-1}$ Mpc$^{-1})$ or more, while providing an equally good fit as $Λ$CDM at $67.73 \pm 0.41$ to higher redshift data, in particular from the cosmic microwave background and baryon acoustic oscillations. These models however do not fully resolve the true source of tension between the distance ladder and high redshift observations: the local calibration of supernovae luminosities well out into the Hubble flow. When tested in this manner by transferring the SH0ES calibration to the Pantheon supernovae dataset, the ability of such transitions to raise the Hubble constant is reduced to $69.17 \pm 1.09$. Such an analysis should also be used when testing any dynamical dark energy model which can produce similarly fine features in redshift or local void models.

Can Late Dark Energy Transitions Raise the Hubble constant?

TL;DR

The paper investigates whether a late-time dark energy transition near the present epoch () can reconcile the Hubble tension by lifting the local value without spoiling high- observables. It introduces a parameterized LDE model with and computes cosmological observables using EFTCAMB, fitting Planck, BAO, and Pantheon data. Two treatments of SH0ES data are tested: a direct constraint and a calibration of Pantheon SN absolute magnitude , revealing that the former can raise to about 74 but does not address the underlying SN calibration issue, while the latter yields only a modest increase and requires an inconsistent -shift. The study concludes that late-time transitions partly relieve but do not fully resolve the Hubble tension, and emphasizes a calibration-based test as essential for evaluating any dynamical dark energy with localized features.

Abstract

Late times dark energy transitions at redshifts can raise the predicted value of the Hubble constant to the SH0ES value, (km s Mpc or more, while providing an equally good fit as CDM at to higher redshift data, in particular from the cosmic microwave background and baryon acoustic oscillations. These models however do not fully resolve the true source of tension between the distance ladder and high redshift observations: the local calibration of supernovae luminosities well out into the Hubble flow. When tested in this manner by transferring the SH0ES calibration to the Pantheon supernovae dataset, the ability of such transitions to raise the Hubble constant is reduced to . Such an analysis should also be used when testing any dynamical dark energy model which can produce similarly fine features in redshift or local void models.

Paper Structure

This paper contains 5 sections, 13 equations, 3 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Late Dark Energy
  3. Datasets and methodology
  4. Hubble Tension vs $H_0$ Values
  5. Discussion

Figures (3)

  • Figure 1: Top: the deviation in the Hubble rate $H(z)$ for the LDE+$H_0$ and LDE+$M$ ML models (Tab. \ref{['tab:parameters']}) relative to the baseline $\Lambda$CDM ML model (Tab. \ref{['tab:LCDM']}). Bottom: Pantheon SN magnitude residuals for the same, offset from the SH0ES calibration by $\Delta M = 0.192$ (see Eq. \ref{['eq:Mshift']}) to emphasize the shape. Both models fit the shape of the SN residuals, LDE+$H_0$ has $H_0\approx 74$, yet both fail to account for this large offset.
  • Figure 2: CMB power spectra residuals with respect to the $\Lambda$CDM ML model for the Planck data and the LDE ML model obtained with the $+ H_0$ dataset (red solid) and the $+ M$ dataset (orange dashed).
  • Figure 3: The marginalized joint posterior for the $\delta$ and $H_0$ parameters in LDE +$H_0$ and LDE +$M$. We also show for comparison the $\Lambda$CDM result for the $H_0$ posterior.