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Related papers: Dynamics of the Cosmological Apparent Horizon: Sur…

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The aim of this work is to model the evolution of the cosmic space based on thermodynamical parameters. The universe is considered to have an apparent horizon radius with a Kodama-Hayward temperature assigned to it. The method is founded on…

General Relativity and Quantum Cosmology · Physics 2015-03-31 M. Hashemi , S. Jalalzadeh , S. Vasheghani Farahani

The fact that one can associate thermodynamic properties with horizons brings together principles of quantum theory, gravitation and thermodynamics and possibly offers a window to the nature of quantum geometry. This review discusses…

General Relativity and Quantum Cosmology · Physics 2015-05-14 T. Padmanabhan

We investigate the thermodynamical properties of the apparent horizon in a fractal universe. We find that one can always rewrite the Friedmann equation of the fractal universe in the form of the entropy balance relation $ \delta Q=T_h…

General Physics · Physics 2015-06-12 Ahmad Sheykhi , Zeinab Teimoori , Bin Wang

In this note, we explore the thermodynamic properties of the universe in the background of the generalized energy-momentum-squared gravity. We derive the energy density of matter from the non-standard continuity equation and use it in our…

General Relativity and Quantum Cosmology · Physics 2021-06-23 Prabir Rudra , Behnam Pourhassan

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

A unified first law of black-hole dynamics and relativistic thermodynamics is derived in spherically symmetric general relativity. This equation expresses the gradient of the active gravitational energy E according to the Einstein equation,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Sean A. Hayward

The cosmological Friedmann equation sourced by the trace anomaly of a conformal field theory that is dual to the five-dimensional Schwarzschild-AdS geometry can be derived from the first law of thermodynamics if the apparent horizon of the…

High Energy Physics - Theory · Physics 2013-11-20 James E. Lidsey

We derive the Friedmann-like equations in braneworld cosmology by imposing the first law of thermodynamics and Bekenstein's area-entropy formula on the apparent horizon of a Friedmann-Roberston-Walker universe in both Randall-Sundrum II…

High Energy Physics - Theory · Physics 2008-11-26 Xian-Hui Ge

Here we consider our universe as inhomogeneous spherically symmetric Lemaitre-Tolman-Bondi Model and analyze the thermodynamics of this model of the universe. The trapping horizon is calculated and is found to coincide with the apparent…

General Relativity and Quantum Cosmology · Physics 2011-05-09 Subenoy Chakraborty , Nairwita Mazumder , Ritabrata Biswas

By following the spirit of arXiv:1003.5665, we define a new Tolman temperature of Kodama observer directly related to its acceleration. We give a generalized integral form of thermodynamics relation on virtual sphere of constant $r$ in…

High Energy Physics - Theory · Physics 2010-09-21 Yi-Xin Chen , Jian-Long Li , Yong-Qiang Wang

We study the relation between the thermodynamics and field equations of generalized gravity theories on the dynamical trapping horizon with sphere symmetry. We assume the entropy of dynamical horizon as the Noether charge associated with…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Shao-Feng Wu , Xian-Hui Ge , Peng-Ming Zhang , Guo-Hong Yang

We analyze the thermodynamic properties of the apparent horizon of Friedmann-Lema\^itre-Roberson-Walker (FLRW) spacetimes in Einstein-Gauss-Bonnet gravity. We use the generalized definition of entropy for gravity theories in higher…

General Relativity and Quantum Cosmology · Physics 2025-10-10 Luis M. Sánchez , Hernando Quevedo

We review thermodynamic properties of modified gravity theories such as $F(R)$ gravity and $f(T)$ gravity, where $R$ is the scalar curvature and $T$ is the torsion scalar in teleparallelism. In particular, we explore the equivalence between…

General Relativity and Quantum Cosmology · Physics 2016-06-22 Kazuharu Bamba

We propose a modified gravity theory by extending the Einstein-Hilbert action with an arbitrary function of the Ricci scalar and the Kretschmann scalar invariants. The resulting modified Friedmann equations for a spatially flat FRW universe…

General Relativity and Quantum Cosmology · Physics 2026-05-29 A. Dehyadegari , A. Sheykhi

We have investigated the thermodynamical properties of the universe with dark energy. It is demonstrated that in a universe with spacial curvature the natural choice for IR cutoff could be the apparent horizon radius. We shown that any…

High Energy Physics - Theory · Physics 2011-07-04 Bin Liu , Xian-Ru Hu , Jian-Bo Deng

A cosmological model based on holographic scenarios is formulated in a flat Friedmann-Robertson-Walker universe. To formulate this model, the cosmological horizon is assumed to have a general entropy and a general temperature (including…

General Relativity and Quantum Cosmology · Physics 2024-01-09 Nobuyoshi Komatsu

We consider a spatially flat Friedmann-Lemaitre-Robertson-Walker space time and investigate the second law and the generalized second law of thermodynamics for apparent horizon in generalized modified Gauss Bonnet theory of gravity (whose…

General Relativity and Quantum Cosmology · Physics 2011-01-17 H. Mohseni Sadjadi

We establish a general thermodynamic scheme for cosmic fluids with internal self-interactions and discuss equilibrium and non-equilibrium aspects of such systems in connection with (generalized) symmetry properties of the cosmological…

Astrophysics · Physics 2009-10-31 Winfried Zimdahl , Alexander B. Balakin

We give a short review of the recent developments of entropic cosmology based on two thermodynamic laws of the apparent horizon, namely the first and the second laws of thermodynamics. The first law essentially provides the change of the…

General Relativity and Quantum Cosmology · Physics 2024-09-04 Shin'ichi Nojiri , Sergei D. Odintsov , Tanmoy Paul

Our aim is to investigate the thermodynamic properties of the universe bounded by the cosmological event horizon and dominated by the tachyon fluid. We give two different laws of evolution of our universe. Further, we show the first law and…

General Relativity and Quantum Cosmology · Physics 2013-10-29 Fei-Quan Tu , Yi-Xin Chen