2026/06/30 by Pranav Prasanthan, Hussain Gohar, Vincenzo Salzano
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Gravitation Theories #Relativity and Gravitational Theory #astro-ph.CO #gr-qc
paper · pdf · doi:10.1016/j.physletb.2026.140778
openalex publication_date 2026/07/01 · openalex created_date 2026/07/24 · openalex updated_date 2026/07/30
We investigate the cosmological implications of the mass-to-horizon relation, which provides a unified framework for thermodynamically consistent generalized horizon-entropy functionals. Using the Cai-Kim formulation of the first law of thermodynamics, we derive the corresponding modified Friedmann equations and examine the resulting background evolution. We find that cosmological viability sharply restricts admissible deviations from the Bekenstein-Hawking area law: phenomenologically acceptable scenarios are confined to a narrow neighborhood of the standard entropy, while more pronounced deviations generically spoil the standard radiation-matter-dark-energy sequence. Power-law entanglement corrections can give rise to a moderate early-dark-energy component, but only within a tightly constrained region of parameter space, whereas quantum-gravity corrections are suppressed by the Planck scale and remain observationally irrelevant. Consequently, all viable models predict a ΛCDM-like cosmological background at the present epoch. These findings demonstrate that background cosmology alone imposes stringent constraints on thermodynamically consistent generalized entropy constructions of this class.