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We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the holographic entropy can be obtained by modifying degeneracy. We…

High Energy Physics - Theory · Physics 2009-03-12 Miao Li , Xiao-Dong Li , Chunshan Lin , Yi Wang

We reconsider the holographic dark energy (HDE) model with a slowly time varying $ c^2(z)$ parameter in the energy density, namely $\rho_D=3M_p^2 c^2(z)/L^2$, where $L$ is the IR cutoff and $z$ is the redshift parameter. As the system's IR…

General Physics · Physics 2017-06-06 A. Sheykhi , S. Ghaffari , N. Roshanshah

Motivated by recent work on consistent fluid couplings in $f(R, T)$ gravity, we study cosmology in the nontrivial model $f(R, T) = R + \sigma R T$ using the Brown variational principle for a barotropic perfect fluid. For a flat FLRW…

General Relativity and Quantum Cosmology · Physics 2026-05-15 Davide Batic , Christian G. Boehmer , Denys Dutykh

The $f(R)$ gravity theory is considered. It is a gravitational theory that generalizes the Einstein-Hilbert action. In this context, a holographic dark energy model is studied. Tsallis non-extensive entropy is used to introduce the dark…

General Relativity and Quantum Cosmology · Physics 2020-12-02 P. S. Ens , A. F. Santos

A cosmological model in an Einstein-Cartan framework endowed with torsion is studied. For a torsion function assumed to be proportional to Hubble expansion function, namely $\phi=-\alpha H$, the contribution of torsion function as a dark…

General Relativity and Quantum Cosmology · Physics 2022-04-27 S. H. Pereira , A. M. Vicente , J. F. Jesus , R. F. L. Holanda

We investigated evolution of metric and density perturbations for Tsallis model of holographic dark energy with energy density $\sim L^{2\gamma - 4}$, where $L$ is length of event horizon or inverse Hubble parameter and $\gamma$ is…

General Relativity and Quantum Cosmology · Physics 2025-08-25 Artyom V. Astashenok , Alexander S. Tepliakov

Using a holographic model, we study quantum field theories with a layer of one CFT surrounded by another CFT, on either a periodic or an infinite direction. We study the vacuum energy density in each CFT as a function of the central…

High Energy Physics - Theory · Physics 2021-09-01 Alex May , Petar Simidzija , Mark Van Raamsdonk

The effective evolution of an inhomogeneous universe model in any theory of gravitation may be described in terms of spatially averaged variables. In Einstein's theory, restricting attention to scalar variables, this evolution can be…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Thomas Buchert

We construct modified cosmological scenarios through the application of the first law of thermodynamics in the universe horizon, but using the generalized, nonextensive Tsallis entropy instead of the usual Bekenstein-Hawking one. We result…

General Relativity and Quantum Cosmology · Physics 2018-12-07 Andreas Lymperis , Emmanuel N. Saridakis

Entropic cosmology with the R\'{e}nyi entropy of the apparent horizon $S_R=(1/\alpha)\ln(1+\alpha S_{BH})$, where $S_{BH}$ is the Bekenstein--Hawking entropy, is studied. By virtue of the thermodynamics-gravity correspondence a model of…

General Physics · Physics 2026-05-04 S. I. Kruglov

Based on Renyi entropy, we study the entropy corrected version of the holographic dark energy (HDE) model in apparent horizon of spatially flat FLRW universe. Applying the generalized entropy leads to the modified version of the Friedmann…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-29 Tayeb Golanbari , Khaled Saaidi , Parvin Karimi

I consider some of the issues we face in trying to understand dark energy. Huge fluctuations in the unknown dark energy equation of state can be hidden in distance data, so I argue that model-independent tests which signal if the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Chris Clarkson

The present work deals with holographic dark energy models with Hubble horizon as the infra-red cut-off. The interaction rate between dark energy and dark matter has been reconstructed with three different choices of the interaction term.…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-17 Purba Mukherjee , Ankan Mukherjee , H. K. Jassal , Ananda Dasgupta , Narayan Banerjee

A Friedmann like cosmological model in Einstein-Cartan framework is studied when the torsion function is assumed to be proportional to a single $\phi(t)$ function coming just from the spin vector contribution of ordinary matter. By…

General Relativity and Quantum Cosmology · Physics 2019-11-21 S. H. Pereira , R. de C. Lima , J. F. Jesus , R. F. L. Holanda

A model for holographic dark energy is proposed, following the idea that the short distance cut-off is related to the infrared cut-off. We assume that the infrared cut-off relevant to the dark energy is the size of the event horizon. With…

High Energy Physics - Theory · Physics 2016-09-06 Miao Li

Gravitational merging (or clustering) of cosmic objects is regarded as a possible source of the extra-acceleration of the universe at large scale. The merging/clustering of cosmic objects introduces a correction term in the equation of…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-29 Mehrdad Khanpour , Ebrahim Yusofi , Bahman Khanpour

The thermodynamics of a scheme of dark matter-dark energy interaction is studied considering a holographic model for the dark energy in a flat Friedmann-Lemaitre-Robertson- Walker background. We obtain a total entropy rate for a general…

High Energy Physics - Theory · Physics 2016-01-05 Fabiola Arevalo , Paulo Cifuentes , Francisco Pena

Interacting dark energy and the holographic principle offer a possible way of addressing the cosmic coincidence problem as well as accounting for the size of the dark energy component. The equilibrium points of the Friedmann equations which…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Micheal S. Berger , Hamed Shojaei

We consider interacting holographic dark energy model in Friedmann Robertson Walker space time with positive spatial curvature and investigate the behavior of curvature parameter and dark energy density in accelerated expanding epoch. We…

General Relativity and Quantum Cosmology · Physics 2021-03-12 H. Mohseni Sadjadi , N. Vadood

We explore the cosmological models of the late-time universe based on the holographic principle, taking into account the properties of the viscosity of the dark fluid. We use the mathematical formalism of generalized infrared cutoff…

General Relativity and Quantum Cosmology · Physics 2021-08-11 I. Brevik , A. V. Timoshkin
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