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Related papers: Observational constraints on Tsallis modified grav…

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We establish new constraints on $f(T)$ gravity models by using cosmological data. In particular, we investigate the restrictions given by the gas mass fraction measurements of galaxy clusters and transversal BAO data. Both data sets are…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-28 F. B. M. dos Santos , J. E. Gonzalez , R. Silva

We investigate the correspondence between Myrzakulov $F(R,Q)$ gravity and Tsallis cosmology. The former is a modified gravity that uses both curvature and nonmetricity, while the latter is a modified cosmology arising from the…

General Relativity and Quantum Cosmology · Physics 2025-02-10 Andreas Lymperis , Gulgassyl Nugmanova , Almira Sergazina

This paper is devoted to study the generalized second law of thermodynamics in $f(T)$ gravity. We use quantum corrections such as power-law and logarithmic corrected entropies to the horizon entropy along with Gibbs' equation in the thermal…

General Relativity and Quantum Cosmology · Physics 2014-12-17 M. Sharif , Shamaila Rani

The present work is devoted to explore some interesting cosmological features of a newly proposed theory of gravity namely $\mathcal{F}(R,L_m,T)$ theory, where $R$ and $T$ represent the Ricci scalar and trace of energy momentum-tensor,…

General Relativity and Quantum Cosmology · Physics 2024-04-09 M. Zubair , Saira Waheed , Quratulien Muneer , M. Ahmad

In this paper, we study thermodynamical properties of the apparent horizon in a universe governed by quasi-topological gravity. Our aim is twofold. First, by using the variational method we derive the general form of Friedmann equation in…

High Energy Physics - Theory · Physics 2015-06-16 M. H. Dehghani , A. Sheykhi , R. Dehghani

In the context of Brans-Dicke scalar tensor theory of gravitation, the cosmological Friedmann equation which relates the expansion rate $H$ of the universe to the various fractions of energy density is analyzed rigorously. It is shown that…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Arik , M. C. Calik , M. B. Sheftel

Employing the thermodynamic unified first law through the thermodynamic-gravity conjecture, in this article, we derive for a FLRW universe the Friedmann equations in the framework of Gauss-Bonnet gravity theory. To do this, we project this…

General Relativity and Quantum Cosmology · Physics 2023-10-16 Joel Saavedra , Francisco Tello-Ortiz

In this article, our goal is to investigate the cosmological dynamics and structure formation in a modified cosmological framework inspired by a generalized mass-to-horizon entropy relation and consistent with the Clausius relation.…

General Relativity and Quantum Cosmology · Physics 2026-04-20 Subhra Mondal , Amitava Choudhuri

We investigate the new observational constraints on $f(T)$ gravity that arise from the effects of primordial gravitational waves (GWs) on the cosmic microwave background (CMB) anisotropies and the BB spectrum. We first show that on the GWs…

General Relativity and Quantum Cosmology · Physics 2018-11-30 Rafael C. Nunes , Supriya Pan , Emmanuel N. Saridakis

Employing the non-additive Tsallis entropy, $S\sim A^{\beta}$, for the large-scale gravitational systems, we disclose that in the cosmological scales both Friedmann equation and the equation of motion for the Newtonian cosmology get…

General Physics · Physics 2020-01-22 Ahmad Sheykhi

We demonstrate that there does exist an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \phi, X)$,…

General Relativity and Quantum Cosmology · Physics 2011-08-05 Kazuharu Bamba , Chao-Qiang Geng , Shinji Tsujikawa

The analysis of phase transitions in cosmological spacetimes shows that their existence requires a time-dependent apparent horizon radius, which in turn implies an equation of state different from that of a dark energy fluid. This condition…

General Relativity and Quantum Cosmology · Physics 2026-01-09 Carlos E. Romero-Figueroa , Hernando Quevedo

We show that it is possible to obtain a picture of equilibrium thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \phi, X)$, where…

General Relativity and Quantum Cosmology · Physics 2010-10-12 Kazuharu Bamba , Chao-Qiang Geng , Shinji Tsujikawa

We investigate the observational implications of Wald--Gauss--Bonnet (WGB) topological dark energy, a modified cosmological framework derived from the gravity-thermodynamics conjecture applied to the Universe's apparent horizon, with the…

General Relativity and Quantum Cosmology · Physics 2025-10-01 Maria Petronikolou , Fotios K. Anagnostopoulos , Stylianos A. Tsilioukas , Spyros Basilakos , Emmanuel N. Saridakis

The present work reveals a direct correspondence between modified theories of gravity (cosmology) and entropic cosmology based on the thermodynamics of apparent horizon. It turns out that due to the total differentiable property of entropy,…

General Relativity and Quantum Cosmology · Physics 2025-07-01 Shin'ichi Nojiri , Sergei D. Odintsov , Tanmoy Paul , Soumitra SenGupta

This work investigates the dynamical evolution of the universe within the framework of symmetric teleparallel $f(Q,\mathcal{T})$ gravity, where $Q$ is the non-metricity scalar and $\mathcal{T}$ is the trace of the energy-momentum tensor. We…

General Relativity and Quantum Cosmology · Physics 2026-05-19 S. H. Shekh , S. B. Thool , Pankaj Kumar , P. C. Kalan , R. M. Dhaigude

We construct new classes of modified theories in which the matter sector couples with the Einstein tensor, namely we consider direct couplings of the latter to the energy-momentum tensor, and to the derivatives of its trace. We extract the…

General Relativity and Quantum Cosmology · Physics 2023-05-17 Petros Asimakis , Spyros Basilakos , Andreas Lymperis , Maria Petronikolou , Emmanuel N. Saridakis

In the present paper, we study the thermodynamics behavior of the field equations for the generalized f(T) gravity with an arbitrary coupling between matter and the torsion scalar. In this regard, we explore the verification of the first…

General Relativity and Quantum Cosmology · Physics 2017-01-17 Tahereh Azizi , Najibeh Borhani

This work presents a universal and revisited formalism for the entropy of the apparent horizon in modified gravity to investigate the validity of the Generalized Second Law (GSL) of thermodynamics. This revisited horizon entropy is…

General Relativity and Quantum Cosmology · Physics 2025-12-22 Soma Heydari , Parastoo Askari , Kayoomars Karami

We investigate the gravitational origin of the Tsallis entropy, characterized by the nonadditive index $\delta$. Utilizing Wald's formalism within the framework of $f(R)$ modified theories of gravity, we evaluate the entropy on the black…

General Relativity and Quantum Cosmology · Physics 2024-09-02 Rocco D'Agostino , Giuseppe Gaetano Luciano