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Related papers: Generalized Misner-Sharp energy in the generalized…

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We investigate the cosmological implications of generalized mass-to-horizon entropy, a two-parameter extension of the standard Bekenstein entropy based on the mass-to-horizon relation. Assuming the entropy balance relation, we derive the…

General Relativity and Quantum Cosmology · Physics 2026-05-26 Smeehan S Shameeem , Priyesh K , Krishna P. B , Titus K Mathew

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 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

This study is conducted to examine the validity of generalized second law of thermodynamics (GSLT) in flat FRW for modified teleparallel gravity involving coupling between a scalar field with the torsion scalar $T$ and the boundary term…

General Relativity and Quantum Cosmology · Physics 2017-07-19 M. Zubair , Sebastian Bahamonde , Mubasher Jamil

The paper deals with universal thermodynamics for FRW model of the universe bounded by apparent (or event) horizon. Assuming Hawking temperature on the horizon, the unified first law is examined on the horizon for different gravity…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

In this work, we have considered a non-canonical scalar field dark energy model in the framework of flat FRW background. It has also been assumed that the dark matter sector interacts with the non-canonical dark energy sector through some…

General Relativity and Quantum Cosmology · Physics 2015-10-12 Sudipta Das , Ujjal Debnath , Abdulla Al Mamon

Rastall generalized Einstein's field equations relaxing the Einstein's assumption that the covariant divergence of the energy-momentum tensor should vanish. His field equations contain a free parameter alpha and in an empty space, i.e. if…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Vladimir Majernik , Lukas Richterek

In black hole physics, the second law of thermodynamics is generally valid whether the black hole is a static or a non-static one. Considering the universe as a thermodynamical system the second law of black hole dynamics extends to the…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Subenoy Chakraborty , Nairwita Mazumder , Ritabrata Biswas

In this work, we have discussed the Maxwell's electrodynamics in non-linear forms in FRW universe. The energy density and pressure for non-linear electrodynamics have been written in the electro-magnetic universe. The Einstein's field…

General Physics · Physics 2012-08-29 Tanwi Bandyopadhyay , Ujjal Debnath

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

Relying on a fundamental empirical identity of heavy and inertial mass it is proposed to bring a status of general theory of relativity (GTR) of Einstein up to a level of Unified Field Theory. To do this, a thoroughgoing revision of…

General Physics · Physics 2016-09-08 Boris Mordvinov

In previous work, a first law of generalized entropy was derived from semiclassical gravitational dynamics around thermal setups using an assumed relation between the matter modular Hamiltonian and the gravitational stress tensor. Allowing…

High Energy Physics - Theory · Physics 2022-04-27 Hong Zhe Chen

In this work, we have considered the magnetic universe in non-linear electrodynamics. The Einstein's field equations for non-flat FRW model have been considered when the universe is filled with the matter and magnetic field only. We have…

General Relativity and Quantum Cosmology · Physics 2015-05-28 Tanwi Bandyopadhyay , Ujjal Debnath

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

Considering the modified entropy-area relation from DSR-GUP (Doubly special relativity-Generalized uncertainity principle), we obtain the modified Friedmann equations from the first law of thermodynamics at apparent horizon. Due to the…

General Relativity and Quantum Cosmology · Physics 2020-04-01 Özgür Ökcü , Christian Corda , Ekrem Aydiner

We study the Misner-Sharp mass for the $f(R)$ gravity in an $n$-dimensional (n$\geq$3) spacetime which permits three-type $(n-2)$-dimensional maximally symmetric subspace. We obtain the Misner-Sharp mass via two approaches. One is the…

General Relativity and Quantum Cosmology · Physics 2014-11-27 Hongsheng Zhang , Yapeng Hu , Xin-Zhou Li

We investigate the generalized second law of thermodynamics (GSL) in generalized theories of gravity. We examine the total entropy evolution with time including the horizon entropy, the non-equilibrium entropy production, and the entropy of…

High Energy Physics - Theory · Physics 2008-12-18 Shao-Feng Wu , Bin Wang , Guo-Hong Yang , Peng-Ming Zhang

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

Considering the Einstein field equations in Lyra manifold, and applying the unified first law of thermodynamics as well as the Clausius relation to the apparent horizon of FRW universe, we find the entropy of apparent horizon in Lyra…

General Relativity and Quantum Cosmology · Physics 2017-09-12 H. Moradpour , N. Sadeghnezhad , S. Ghaffari , A. Jahan

We derive the modified Friedmann equation corresponding to the power-law corrected entropy-area relation $S_{\rm A}=\frac{A}{4}[1-K_{\alpha} A^{1-\frac{\alpha}{2}}]$ which is motivated by the entanglement of quantum fields in and out of the…

General Physics · Physics 2011-09-07 K. Karami , A. Abdolmaleki , N. Sahraei , S. Ghaffari