Diffusive dark fluids with Planck-2018 and DESI BAO DR2 Measurements

TL;DR

This study constrains a diffusive dark fluid cosmological model using Planck 2018 CMB data and DESI DR2 BAO measurements, analyzing its impact on cosmic evolution, structure formation, and the Hubble constant discrepancy.

Contribution

It extends previous work by incorporating new observational data to constrain the diffusive dark fluid model and examines its effects on cosmological parameters and structure formation.

Findings

Discrepancies in H_0 measurements are minimal between the model and Planck values.

The interaction influences cosmic evolution and structure formation.

The model's H_0 estimates are consistent with observational data.

Abstract

In this paper, we constrain the diffusive dark fluid cosmological model, which is the interacting dark energy framework, wherein energy is transferred between the two dark components through a diffusion process. We extended the work by S. Sahlu et al. (2026) by employing Cosmic Microwave Background (CMB) data from the Planck 2018 measurements in combination with Baryon Acoustic Oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI) DR2 (2024).From the results, we found that the discrepancies in $H_0$ measurements are $0.0105\sigma$ and $1.29\sigma$ between the Planck 2018 value $(H_0 = 67.4\pm0.5\ \mathrm{km,s^{-1},Mpc^{-1}})$ and our diffusive model values, $H_0 = 67.3876^{+1.0765}_{-1.0709}$ and $68.3804^{+0.5639}_{-0.5852}$, respectively. We also the we observe that the effects of the interaction on cosmic evolution and structure formation; we emphasize this by computing the scale-dependent density contrast and the matter power spectrum, compared with the $\Lambda$CDM model.