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arXiv · 2604.22450

Exploring R\'enyi Entropic Cosmology Constrained by DESI DR2 BAO and Complementary Late-Time Observations

Rajdeep Mazumdar·Kalyan Malakar·Kalyan Bhuyan
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Abstract

We investigate the late-time cosmological viability of R\'enyi entropic cosmology (REC) by confronting its modified Friedmann dynamics with DESI DR2 BAO, cosmic chronometers, gravitational-wave standard sirens, redshift-space distortions, and two independent Type Ia supernova compilations, PantheonPlus and Union3. Unlike earlier works, we obtain a stringent constraint on the R\'enyi parameter $\lambda \sim (3.7\text{--}3.8)\times10^{-124}$, with the resulting value even satisfying recent Big Bang Nucleosynthesis and baryogenesis bounds. Across all observational combinations, REC yields $H_0\simeq68.2$--$68.4$ $km\,s^{-1}\,Mpc^{-1}$ and $\Omega_{m0}\simeq0.291$--$0.295$, with a transition from deceleration to acceleration at $z_{\rm tr}\simeq0.66$--$0.68$. The effective equation of state remains quintessence-like, with $w_{\rm eff}(0)\simeq-0.68$, and does not cross the phantom boundary. REC provides a modest improvement in the minimum $\chi^2$ relative to $\Lambda$CDM, while the AIC, DIC, BIC, and Bayesian evidence indicate that the preference for REC is statistically competitive but not decisive. Conclusively, the results show that R\'enyi entropy can produce a controlled modification of the late-time expansion history while remaining observationally close to $\Lambda$CDM.

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Rajdeep Mazumdar, Kalyan Malakar, Kalyan Bhuyan. 2026-04-24. Exploring R\'enyi Entropic Cosmology Constrained by DESI DR2 BAO and Complementary Late-Time Observations. https://arxiv.org/abs/2604.22450

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