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Related papers: The Apparent Universe

200 papers

In this work we present the cosmological dynamics of interacting dark energy models in the framework of particle creation mechanism. The particle creation mechanism presented here describes the true non equilibrium thermodynamics of the…

General Relativity and Quantum Cosmology · Physics 2017-06-07 Sujay Kr. Biswas , Wompherdeiki Khyllep , Jibitesh Dutta , Subenoy Chakraborty

Inspired by the entropy-area relation of black hole thermodynamics, we study the thermodynamics of cosmological apparent horizon in a spatially flat Friedmann-Robertson-Walker (FRW) universe in the framework of an Extended Uncertainty…

General Relativity and Quantum Cosmology · Physics 2024-08-29 Maryam Roushan , Narges Rashidi , Kourosh Nozari

We consider a simple physical model for an evolving horizon that is strongly interacting with its environment, exchanging arbitrarily large quantities of matter with its environment in the form of both infalling material and outgoing…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Alex B. Nielsen , Matt Visser

It is a remarkable fact that all processes occurring in the observable Universe are irreversible, whereas the equations through which the fundamental laws of physics are formulated are invariant under time reversal. The emergence of…

General Physics · Physics 2015-05-28 Gustavo E. Romero , Daniela Pérez

A novel idea that the cosmic acceleration can be understood from the perspective that spacetime dynamics is an emergent phenomena was proposed by T. Padmanabhan. The Friedmann equations of FRW universe can be derived from different gravity…

General Relativity and Quantum Cosmology · Physics 2014-03-04 Wen-Yuan Ai , Xian-Ru Hu , Hua Chen , Jian-Bo Deng

Starting from the first law of thermodynamics, $dE=T_hdS_h+WdV$, at apparent horizon of a FRW universe, and assuming that the associated entropy with apparent horizon has a quantum corrected relation, $S=\frac{A}{4G}-\alpha \ln…

High Energy Physics - Theory · Physics 2011-02-09 Ahmad Sheykhi

Astrophysical observations provide a picture of the universe as a 4-dim homogeneous and isotropic flat space-time dominated by an unknown form of dark energy. To achieve such a cosmology one has to consider in the early universe an…

Astrophysics · Physics 2009-11-10 F. Canfora , A. Troisi

In this note, we discuss how possible expansion histories of the universe can be inferred in a simple way, for arbitrary energy contents. No new physical results are obtained, but the goal is rather to discuss an alternative way of writing…

General Physics · Physics 2016-08-03 Edvard Mortsell

A simple quantum mechanical model of $N$ free scalar fields interacting with a dynamical moving mirror is formulated and shown to be equivalent to two-dimensional dilaton gravity. We derive the semi-classical dynamics of this system, by…

High Energy Physics - Theory · Physics 2010-11-01 Tze-Dan Chung , Herman Verlinde

We analyze the apparent horizon dynamics in the inhomogeneous Clifton-Mota-Barrow solution of Brans-Dicke theory. This solution models a central matter configuration embedded in a cosmological background. In certain regions of the parameter…

General Relativity and Quantum Cosmology · Physics 2013-03-01 Vincenzo Vitagliano , Valerio Faraoni , Thomas P. Sotiriou , Stefano Liberati

In this letter we construct a new time-periodic solution of the vacuum Einstein's field equations whose Riemann curvature norm takes the infinity at some points. We show that this solution is intrinsically time-periodic and describes a…

Mathematical Physics · Physics 2008-09-02 De-Xing Kong , Kefeng Liu , Ming Shen

For the centennial of quantum mechanics, we offer an overview of the central role played by quantum information and thermalization in problems involving fundamental properties of spacetime and gravitational physics. This is an open area of…

General Relativity and Quantum Cosmology · Physics 2026-01-26 C. R. Ordonez , A. Chakraborty , H. E. Camblong , M. O. Scully , W. G. Unruh

Recent observations show that our universe is accelerating by dark energy, so it is important to investigate the thermodynamical properties of it. The Undulant Universe is a model with equation of state $\omega(a)=-\cos(b\ln a)$ for dark…

Astrophysics · Physics 2010-06-18 Tian Lan , Tong-Jie Zhang , Bao-Quan Wang

The classic black hole mechanics and thermodynamics are formulated for stationary black holes with event horizons. Alternative theories of gravity of interest for cosmology contain a built-in time-dependent cosmological "constant" and black…

General Relativity and Quantum Cosmology · Physics 2018-10-12 Valerio Faraoni

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

Utilizing Kaniadakis entropy associated with the apparent horizon of the Friedmann-Robertson-Walker (FRW) Universe and applying the emergence of cosmic space paradigm, we deduce the modified Friedmann equation for a non-flat…

General Relativity and Quantum Cosmology · Physics 2024-05-08 Pranav Prasanthan , Sarath Nelleri , Navaneeth Poonthottathil , Sreejith E K

We show that the accelerated expansion of the Universe can be viewed as a crossover phenomenon where the Newton constant and the Cosmological constant are actually scaling operators, dynamically evolving in the attraction basin of a…

Astrophysics · Physics 2009-11-13 A. Bonanno , G. Esposito , C. Rubano , P. Scudellaro

There is sufficient amount of internal evidence in the nature of gravitational theories to indicate that gravity is an emergent phenomenon like, e.g, elasticity. Such an emergent nature is most apparent in the structure of gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 T. Padmanabhan

Based on Padmanabhan's theory, the spatial expansion of the Universe can be explained by the emergence of space as cosmic time progresses. To further explore this idea, we have developed fractional-fractal Friedmann and Raychaudhuri…

General Relativity and Quantum Cosmology · Physics 2023-09-29 P. F. da Silva Junior , E. W. de Oliveira Costa , S. Jalalzadeh

We study the Barrow cosmological model, which proposes that quantum gravity effects create a complex, fractal structure for the universe's apparent horizon. We leverage the thermodynamics - gravity conjecture. By applying the Clausius…

General Relativity and Quantum Cosmology · Physics 2025-01-22 Mahnaz Asghari , Alireza Allahyari , David F. Mota