English

Addressing the Hubble Tension: Insights from Reversible and Irreversible Thermodynamic Processes

General Relativity and Quantum Cosmology 2026-03-12 v2 Cosmology and Nongalactic Astrophysics

Abstract

We investigate reversible and irreversible thermodynamic processes in cosmology and their impact on the Hubble tension. Gravitationally induced adiabatic matter creation/annihilation is treated as irreversible, while energy exchange between the cosmic bulk and horizon is modeled as reversible. Two scenarios are proposed: Model I features matter creation/annihilation across all species with energy transfer to effective entropic dark energy; Model II considers dark matter creation/annihilation with energy flow from baryonic matter and radiation. The creation rate is parameterized as Γ(t)=Γ0H\Gamma(t)=\Gamma_0 H, with energy transfer controlled by γ\gamma. We constrain both models using Pantheon++ supernovae, CMB distance priors, baryon acoustic oscillations, gamma-ray bursts, and cosmic chronometers, with and without SH0_0ES. When SH0_0ES is included, matter annihilation (Γ0<0\Gamma_0<0) is statistically preferred, yielding H0=71.75±0.79H_0 = 71.75 \pm 0.79 km s1^{-1} Mpc1^{-1} (Model I) and H0=71.06±0.81H_0 = 71.06 \pm 0.81 km s1^{-1} Mpc1^{-1} (Model II), corresponding to 1.2σ1.2\sigma and 1.8σ1.8\sigma consistency with the SH0_0ES value 73.17±0.8673.17 \pm 0.86 km s1^{-1} Mpc1^{-1}. Matter creation (Γ0>0\Gamma_0>0) or pure energy flow (Γ=0\Gamma=0) do not improve the tension. Without SH0_0ES, information criteria show no preference over Λ\LambdaCDM. For the matter annihilation/creation with energy flow, the effective entropic dark energy evolves dynamically, mimicking radiation and matter before recombination and approaching a cosmological constant at late times. These results demonstrate that thermodynamically motivated interactions can alleviate the Hubble tension when calibrated with local measurements, while remaining consistent with cosmological data.

Keywords

Cite

@article{arxiv.2507.05854,
  title  = {Addressing the Hubble Tension: Insights from Reversible and Irreversible Thermodynamic Processes},
  author = {Hussain Gohar},
  journal= {arXiv preprint arXiv:2507.05854},
  year   = {2026}
}

Comments

21 pages, 13 figures, 8 tables. Abstract shortened to satisfy the arXiv character limit (full version in PDF). Models extended to include separate analyses of reversible and irreversible processes. Discussion and results expanded. Accepted for publication in Phys. Rev. D