M. Motaghi | Searcharxiv

arXiv2026

Hints Beyond $\Lambda$CDM from Barrow and Tsallis Holographic Dark Energy with GO cutoff

Barrow and Tsallis Holographic Dark Energy (HDE) are two recent extensions of the standard HDE framework, obtained by introducing generalized entropy corrections through the Barrow and Tsallis formalisms. In this work, we examine the cosmological consequences of Barrow and Tsallis HDE implemented with the Granda-Oliveros (GO) infrared (IR) cutoff. After deriving the modified Friedmann equations within the thermodynamic-gravity conjecture, we study the background evolution in both non-interacting and interacting dark sector scenarios, emphasizing the role of the entropic parameter in shaping late-time dynamics. We then confront the model with state-of-the-art observations, including PantheonPlus and Union3 Type Ia supernovae, Cosmic Chronometers and DESI DR2 BAO measurements. Using Bayesian MCMC methods, we constrain the model parameters and compare the performance of BHDE with that of $\Lambda$CDM. Our results show that BHDE is compatible with current data and can exhibit a mild statistical preference over the concordance model for certain dataset combinations. Overall, the analysis underscores the relevance of generalized entropy frameworks in late-time cosmology and identifies Barrow-Tsallis holography with the GO cutoff as a competitive alternative to $\Lambda$CDM.

gr-qc↗

arXiv2024

Holographic dark energy in Barrow cosmology with Granda-Oliveros IR cutoff

Applying the modified Barrow entropy, inspired by the quantum fluctuation effects, to the cosmological background, and using thermodynamics-gravity conjuncture, the Friedmann equations get modified as well. In this paper, we explore the holographic dark energy with Granda-Oliveros (GO) IR cutoff, in the context of the modified Barrow cosmology. First, we assume two dark components of the universe evolves independently and obtain the cosmological parameters and explore the cosmic evolution. Second, we consider an interaction term between dark energy (DE) and dark matter (DM). We observe that the Barrow parameter $δ$ crucially affects the cosmic dynamics, causes the transition from the decelerating phase to the accelerating phase occurs later. We find out that the equation of state parameter is in the quintessence region in the past and crosses the phantom divide at the present time. Finally, we examine the squared speed of sound analysis for this model. According to the squared sound speed diagrams, the results indicate that the presence of interaction between DM and DE as well as increasing in the value of $δ$ leads to the manifestation of signs of instability in the past $(v_s^2<0)$. Furthermore, by examining the statefinder, we find that presence of $δ$ also makes a distinction between holographic dark energy in Barrow cosmology with GO-IR cutoff and the $Λ$CDM model. In fact, increasing $δ$ causes the statefinder diagram move away from the point of $\left\lbrace r,s\right\rbrace= \left\lbrace 1,0\right\rbrace$ at $z=0$.

gr-qc↗