Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Decay of $f(R)$ quintessence into dark matter: mitigating the Hubble tension?

Giovanni Montani, Luis A. Escamilla, Nakia Carlevaro, Eleonora Di Valentino

TL;DR

This work investigates a modified gravity approach to the Hubble tension by embedding metric $f(R)$ gravity in the Jordan frame, where a non-minimally coupled scalar field is split into a nearly GR background and a rapidly varying fluctuation that decays into dark matter. The authors derive a late-time, four-parameter model characterized by the present dark-energy fluctuation amplitude $\delta\phi_0$ and a normalized decay rate $\ξ_0$, and constrain it with low-redshift data via MCMC. The results show a modest improvement in fitting CC, SN, BAO, and SH0ES data and a higher inferred $H_0$ relative to $\Λ$CDM, with a late-time transition around $z\sim1$ that mimics DM creation; however, Bayesian evidence remains inconclusive due to model complexity. The analysis suggests that interacting dark sector scenarios within modified gravity can partially alleviate the Hubble tension and merit further study, especially including CMB and perturbation-level data to fully assess viability.

Abstract

We propose a revised cosmological scenario that extends the $Λ$ Cold Dark Matter ($Λ$CDM) framework by incorporating metric $f(R)$ gravity in the Jordan frame. In this model, the dark energy component arises from a non-minimally coupled scalar field, decomposed into a smooth background (set to unity to recover General Relativity) and a rapidly varying, massive fluctuation that decays into the dark matter sector. In the near-GR limit, this setup provides a phenomenological extension of $Λ$CDM characterized by two additional parameters: the present-day value of the scalar fluctuation and a normalized decay rate. Using a Markov Chain Monte Carlo analysis of low-redshift cosmological data, comprising Type Ia Supernovae, Baryon Acoustic Oscillation (BAO), and Cosmic Chronometer measurements, we find that the proposed model achieves a better overall fit than $Λ$CDM, while the Bayesian evidence remains statistically inconclusive given the inclusion of two extra parameters. The model predicts a moderate increase in the inferred value of $H_0$ and an improved consistency with DESI BAO data when adopting the SH0ES prior. Furthermore, describing dark matter particle creation as a transition phase in the late Universe offers an intriguing physical interpretation, potentially capturing features already present in current data and providing a promising avenue to explore extensions of the standard cosmological model within modified gravity frameworks.

Decay of $f(R)$ quintessence into dark matter: mitigating the Hubble tension?

TL;DR

This work investigates a modified gravity approach to the Hubble tension by embedding metric gravity in the Jordan frame, where a non-minimally coupled scalar field is split into a nearly GR background and a rapidly varying fluctuation that decays into dark matter. The authors derive a late-time, four-parameter model characterized by the present dark-energy fluctuation amplitude and a normalized decay rate , and constrain it with low-redshift data via MCMC. The results show a modest improvement in fitting CC, SN, BAO, and SH0ES data and a higher inferred relative to CDM, with a late-time transition around that mimics DM creation; however, Bayesian evidence remains inconclusive due to model complexity. The analysis suggests that interacting dark sector scenarios within modified gravity can partially alleviate the Hubble tension and merit further study, especially including CMB and perturbation-level data to fully assess viability.

Abstract

We propose a revised cosmological scenario that extends the Cold Dark Matter (CDM) framework by incorporating metric gravity in the Jordan frame. In this model, the dark energy component arises from a non-minimally coupled scalar field, decomposed into a smooth background (set to unity to recover General Relativity) and a rapidly varying, massive fluctuation that decays into the dark matter sector. In the near-GR limit, this setup provides a phenomenological extension of CDM characterized by two additional parameters: the present-day value of the scalar fluctuation and a normalized decay rate. Using a Markov Chain Monte Carlo analysis of low-redshift cosmological data, comprising Type Ia Supernovae, Baryon Acoustic Oscillation (BAO), and Cosmic Chronometer measurements, we find that the proposed model achieves a better overall fit than CDM, while the Bayesian evidence remains statistically inconclusive given the inclusion of two extra parameters. The model predicts a moderate increase in the inferred value of and an improved consistency with DESI BAO data when adopting the SH0ES prior. Furthermore, describing dark matter particle creation as a transition phase in the late Universe offers an intriguing physical interpretation, potentially capturing features already present in current data and providing a promising avenue to explore extensions of the standard cosmological model within modified gravity frameworks.
Paper Structure (9 sections, 40 equations, 2 figures, 1 table)

This paper contains 9 sections, 40 equations, 2 figures, 1 table.

Table of Contents

  1. Introduction
  2. Metric $f(R)$-gravity
  3. Dynamics setup
  4. Proposed paradigm
  5. Reduced dimensionless model
  6. Model dynamics near GR
  7. Methodology of data analysis
  8. Results and discussion
  9. Conclusions

Figures (2)

  • Figure 1: Triangle plot showing the 1D and 2D marginalized posteriors from the parameter inference analysis. Since the parameter $\delta\phi_0$ spans several orders of magnitude, we show its logarithm instead.
  • Figure 2: Plots showing the normalized $H(z)$. Upper: Normalized $H(z)$ in the redshift range $0<z<3$. Lower: Normalized $H(z)$ in the range $0.4<z<3.0$, including the line-of-sight BAO data from DESI DR2.