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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

This work is to study the generalized second law (GSL) of thermodynamics in tachyon cosmology where the boundary of the universe is assumed to be enclosed by a dynamical apparent horizon. The model is constrained with the observational…

General Relativity and Quantum Cosmology · Physics 2016-06-08 H. Farajollahi , A. Ravanpak , H. Shojaie , M. Abolghasemi

We study the modified Friedmann equation in the Friedmann-Robertson-Walker universe with quantum effect. Our modified results mainly stem from the new entropy-area relation and the novel idea of T. Padmanabhan, who considers the cosmic…

General Relativity and Quantum Cosmology · Physics 2018-03-15 Wei Zhang , Xiao-Mei Kuang

Recently, a novel idea about our expanding Universe was proposed by T. Padmanabhan [arXiv:1206.4916]. He suggested that the expansion of our Universe can be thought of as the emergence of space as cosmic time progresses. The emergence is…

High Energy Physics - Theory · Physics 2012-11-13 Ke Yang , Yu-Xiao Liu , Yong-Qiang Wang

The present work shows that the second law of thermodynamics gets naturally satisfied during the entire cosmic evolution of the universe starting from inflation to the late dark energy era, without imposing any exotic condition. This makes…

General Relativity and Quantum Cosmology · Physics 2025-02-05 Sergei D. Odintsov , Tanmoy Paul , Soumitra SenGupta

We investigate the thermodynamic and phenomenological implications of a cosmological model governed by fractional entropy applied to the apparent horizon of a flat Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) universe. By utilizing the…

General Relativity and Quantum Cosmology · Physics 2026-04-21 Miguel Cruz , Diego da Silva , Simón González , Samuel Lepe , Joel Saavedra , Manuel Gonzalez-Espinoza

We exploit the parallel between dynamical black holes and cosmological spacetimes to describe the evolution of Friedmann-Lema\^itre-Robertson-Walker universes from the point of view of an observer in terms of the dynamics of the apparent…

General Relativity and Quantum Cosmology · Physics 2015-10-07 Pierre Binétruy , Alexis Helou

This article is devoted to the study of the thermodynamics phase transitions and critical phenomena of an FLRW cosmological model under the so-called Kaniadakis's statistics. The equation of state is derived from the corrected Friedmann…

General Relativity and Quantum Cosmology · Physics 2024-05-09 Joaquin Housset , Joel F. Saavedra , Francisco Tello-Ortiz

It has been shown that Friedmann equation of FRW universe can be derived from the idea which says cosmic space is emergent as cosmic time progresses and our universe is expanding towards the state with the holographic equipartition by…

High Energy Physics - Theory · Physics 2015-06-15 Fei-Quan Tu , Yi-Xin Chen

In this paper, we study a big bounce universe typified by a non-singular big bounce, as opposed to a singular big bang. This cosmological model can describe radiation dominated early universe and matter dominated late universe in FRW model.…

General Relativity and Quantum Cosmology · Physics 2016-04-15 Molin Liu , Yuling Yang , Jianbo Lv , Lixin Xu

As soon as an interaction between holographic dark energy and dark matter is taken into account, the identification of IR cutoff with Hubble radius $H^{-1}$, in flat universe, can simultaneously drive accelerated expansion and solve the…

High Energy Physics - Theory · Physics 2010-01-06 Ahmad Sheykhi

We study thermodynamics of the apparent horizon in $F(R)$ gravity. In particular, we demonstrate that a $F(R)$ gravity model with realizing a crossing of the phantom divide can satisfy the second law of thermodynamics in the effective…

High Energy Physics - Theory · Physics 2009-09-28 Kazuharu Bamba , Chao-Qiang Geng

The generalized second law of gravitational thermodynamics is applied to the present era of accelerated expansion of the Universe. In spite of the fact that the entropy of matter and relic gravitational waves inside the event horizon…

General Relativity and Quantum Cosmology · Physics 2009-11-11 German Izquierdo , Diego Pavon

Applying the Clausius relation, $\delta Q=TdS$, to the apparent horizon of FRW universe in brane world scenarios, we show that an explicit entropy expression associated with the apparent horizon can be obtained. On the apparent horizon, the…

High Energy Physics - Theory · Physics 2008-11-26 Rong-Gen Cai

The general relativistic cosmological Friedmann equations which describe how the scale factor of the universe evolves are expanded explicitly to include energy forms not usually seen. The evolution of the universe as predicted by the…

Astrophysics · Physics 2008-11-26 Robert J. Nemiroff , Bijunath Patla

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

In a recent paper [arXiv:1206.4916] by T. Padmanabhan, it was argued that our universe provides an ideal setup to stress the issue that cosmic space is emergent as cosmic time progresses and that the expansion of the universe is due to the…

General Relativity and Quantum Cosmology · Physics 2012-11-09 Rong-Gen Cai

We explore the thermodynamic and entanglement properties of dynamical black holes based on the recently proposed dynamical black hole entropy by Hollands-Wald-Zhang. We first provide direct proof that, under first-order perturbations, the…

High Energy Physics - Theory · Physics 2026-05-20 Weizhen Jia , Qiongyu Qi , Christina Gao

Cosmological adiabatic particle creation results in the generation of irreversible entropy. The evolution of this entropy is examined in a flat Friedmann--Robertson--Walker universe at late times, using a dissipative model with a power-law…

General Relativity and Quantum Cosmology · Physics 2020-09-16 Nobuyoshi Komatsu

The thermodynamic properties of loop quantum cosmology (LQC) without considering the Lorentz term were established in \cite{Zhu09}. In this paper, we extend this result to the recent proposed new model of LQC with the Lorentz term. We…

General Relativity and Quantum Cosmology · Physics 2021-11-11 Xiangdong Zhang