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Related papers: Thermodynamics in Modified Gravity Theories

200 papers

The present work deals with a detailed study of universal thermodynamics in different modified gravity theories. The validity of the generalized second law of thermodynamics (GSLT) and thermodynamical equilibrium (TE) of the Universe…

General Relativity and Quantum Cosmology · Physics 2016-11-02 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

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

By refining the method proposed in arXiv:2010.07660, entropy current and entropy density for a relativistic hydrostatic equilibrium system with spherical symmetry are constructed as a non-Noether conserved charge in the Einstein gravity…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Shuichi Yokoyama

We investigate thermodynamics of apparent horizon in the $f(Q)$ universe with trivial and nontrivial connections. We first explore the perspectives of the first law, generalized second law and $P-V$ phase transition with trivial connection.…

General Relativity and Quantum Cosmology · Physics 2024-06-14 Haomin Rao , Chunhui Liu , Chao-Qiang Geng

We develop new modified cosmological scenarios by applying the first law of thermodynamics at the Universe horizon, utilizing a new entropic functional that generalizes the standard Boltzmann-Gibbs-Shannon entropy. In particular, starting…

General Relativity and Quantum Cosmology · Physics 2026-02-24 G. G. Luciano , E. N. Saridakis

Thermodynamics of local causal horizons have been shown to encode the information necessary to derive the equations governing the gravitational dynamics. We have previously shown that, in the presence of matter, this derivation further…

General Relativity and Quantum Cosmology · Physics 2025-09-23 Ana Alonso-Serrano , Marek Liška

We have investigated the thermodynamical properties of the Universe with dark energy. Adopting the usual assumption in deriving the constant co-moving entropy density that the physical volume and the temperature are independent, we observed…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Yungui Gong , Bin Wang , Anzhong Wang

The Clausius relation between entropy change and heat flux has previously been used to derive Einstein's field equations as an equation of state. In that derivation the entropy is proportional to the area of a local causal horizon, and the…

General Relativity and Quantum Cosmology · Physics 2013-05-30 Raf Guedens , Ted Jacobson , Sudipta Sarkar

The thermodynamical study of the universe allow particle production in modified $f(T)$ ($T$ is the torsion scalar) theory of gravity within a flat FLRW framework for line element. The torsion scalar $T$ plays the same role as the Ricci…

General Relativity and Quantum Cosmology · Physics 2021-01-18 Sanjay Mandal , P. K. Sahoo

We study the thermodynamics of some cosmological models based on modified gravity, a braneworld with induced gravity and curvature effect. Dark energy component seems necessary if the models are to approach thermal equilibrium in the long…

General Relativity and Quantum Cosmology · Physics 2011-09-16 Ninfa Radicella , Diego Pavón

We revisit Jacobson's thermodynamic derivation of gravitational dynamics in the presence of generalized, non-extensive horizon entropies. Working within a local Rindler-wedge framework, we formulate the Clausius relation as the stationarity…

General Relativity and Quantum Cosmology · Physics 2026-03-06 Marco Figliolia , Petr Jizba , Gaetano Lambiase

The Friedmann equations of general relativity can be derived from the first law of thermodynamics when the entropy of the apparent horizon of a spatially isotropic universe is given by the Bekenstein-Hawking entropy. We point out that if…

General Relativity and Quantum Cosmology · Physics 2009-11-19 James E. Lidsey

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

Using the first law of thermodynamics, we propose a relation between the system entropy ($S$) and its IR ($L$) and UV ($\Lambda$) cutoffs. In addition, applying this relation to the apparent horizon of flat FRW universe, whose entropy meets…

General Physics · Physics 2018-10-18 H. Moradpour , S. A. Moosavi , I. P. Lobo , J. P. Morais Graça , A. Jawad , I. G. Salako

The review is devoted to consideration of possible observational consequences of modified gravity theories, suggested for explanation of the contemporary accelerated expansion of the universe. The major attention is paid to F(R)-models. It…

General Relativity and Quantum Cosmology · Physics 2019-11-11 Elena Arbuzova

We analyze black hole thermodynamics in a generalized theory of gravity whose Lagrangian is an arbitrary function of the metric, the Ricci tensor and a scalar field. We can convert the theory into the Einstein frame via a "Legendre"…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Jun-ichirou Koga , Kei-ichi Maeda

In the paper, hep-th/0501055 (R.G. Cai and S.P. Kim, JHEP {\bf 0502}, 050 (2005)), it is shown that by applying the first law of thermodynamics to the apparent horizon of an FRW universe and assuming the geometric entropy given by a quarter…

High Energy Physics - Theory · Physics 2008-11-26 M. Akbar , Rong-Gen Cai

We consider the thermodynamics of a horizon surface from the viewpoint of the vacuum tension $\tau =(c^4/4G )$. Numerically, $\tau \approx 3.026\times 10^{43}$ Newton. In order of magnitude, this is the tension that has been proposed for…

General Relativity and Quantum Cosmology · Physics 2016-02-10 A. Widom , J. Swain , Y. N. Srivastava

We review recent progress in understanding certain aspects of the thermodynamics of black holes and other horizons. Our discussion centers on various ``entropy bounds'' which have been proposed in the literature and on the current…

High Energy Physics - Theory · Physics 2017-08-23 Donald Marolf

A general formalism for understanding the thermodynamics of horizons in spherically symmetric spacetimes is developed. The formalism reproduces known results in the case of black hole spacetimes. But its power lies in being able to handle…

General Relativity and Quantum Cosmology · Physics 2010-11-19 T. Padmanabhan