Tsallis Holographic Dark Energy with varying Gravitational Constant vs ΛCDM : A Comparative Outlook
Abstract
We investigate the cosmological evolution of a flat Friedmann--Robertson--Walker Universe filled with Tsallis holographic dark energy (THDE) under the assumption that the gravitational constant G varies with time according to the power-law parametrisation dln G / dln a = αG = const. In this framework, the holographic dark energy density is given by ρDE ∝ L2γ− 4, where L is the future event horizon and γ is the Tsallis non-additivity parameter. We study both the past and future evolution of the Universe for various values of the model parameters C, γ, and αG. The viability of the model is tested against a combination of observational data, including the Pantheon+ Type Ia supernova sample, direct Hubble parameter measurements H(z), and baryon acoustic oscillation (BAO) data. Using Markov Chain Monte Carlo (MCMC) methods and Bayesian analysis tools such as the Deviance Information Criterion (DIC), the Bayes factor, and the suspiciousness metric, we perform a rigorous statistical comparison with the standard ΛCDM model. Our results show that models with a varying gravitational constant are preferred over ΛCDM. The best fit to the combined data is obtained for the THDE model with C < 1. Furthermore, we analyse the internal consistency of the data sets using the Index of Inconsistency, the QDMAP statistic, and Bayesian suspiciousness. We find that the THDE model with varying G and C < 1 partially alleviates the tensions between different probes, reducing the significance from ∼ 7.4σ to ∼ 5.3σ.
Versions
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BibTeX
@misc{astashenok2026tsallis,
title = {{Tsallis Holographic Dark Energy with varying Gravitational Constant vs $Λ$CDM : A Comparative Outlook}},
author = {Artyom V. Astashenok and Alexander S. Tepliakov},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.23592},
eprint = {2608.23592},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.23592},
}
RIS
TY - UNPB
TI - Tsallis Holographic Dark Energy with varying Gravitational Constant vs ΛCDM : A Comparative Outlook
AU - Artyom V. Astashenok
AU - Alexander S. Tepliakov
PY - 2026
DA - 2026/10/25
PB - arXiv
DO - 10.48550/arxiv.2608.23592
UR - https://arxiv.org/abs/2608.23592
AB - We investigate the cosmological evolution of a flat Friedmann--Robertson--Walker Universe filled with Tsallis holographic dark energy (THDE) under the assumption that the gravitational constant G varies with time according to the power-law parametrisation dln G / dln a = α_G = const. In this framework, the holographic dark energy density is given by ρ_DE ∝ L^2γ− 4, where L is the future event horizon and γ is the Tsallis non-additivity parameter. We study both the past and future evolution of the Universe for various values of the model parameters C, γ, and α_G. The viability of the model is tested against a combination of observational data, including the Pantheon+ Type Ia supernova sample, direct Hubble parameter measurements H(z), and baryon acoustic oscillation (BAO) data. Using Markov Chain Monte Carlo (MCMC) methods and Bayesian analysis tools such as the Deviance Information Criterion (DIC), the Bayes factor, and the suspiciousness metric, we perform a rigorous statistical comparison with the standard ΛCDM model. Our results show that models with a varying gravitational constant are preferred over ΛCDM. The best fit to the combined data is obtained for the THDE model with C < 1. Furthermore, we analyse the internal consistency of the data sets using the Index of Inconsistency, the Q_DMAP statistic, and Bayesian suspiciousness. We find that the THDE model with varying G and C < 1 partially alleviates the tensions between different probes, reducing the significance from ∼ 7.4σ to ∼ 5.3σ.
ER -