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We examine the definition S = ln Omega as a candidate "gravitational entropy" function. We calculate its behavior for gravitationl and density perturbations in closed, open and flat cosmologies and find that in all cases it increases…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Tony Rothman

In this thesis, we study the Hamiltonian and covariant phase space description of gravitational theories. The phase space represents the allowed field configurations and is accompanied by a closed nondegenerate 2 form- the symplectic form.…

High Energy Physics - Theory · Physics 2016-03-09 Ali Seraj

Along recent decades, an intensive worldwide research activity is focusing both black holes and cosmos (e.g. the dark-energy phenomenon) on the basis of entropic approaches. The Boltzmann-Gibbs-based Bekenstein-Hawking entropy…

Statistical Mechanics · Physics 2024-08-19 Constantino Tsallis , Henrik Jeldtoft Jensen

A general ansatz for gravitational entropy can be provided using the criterion that, any patch of area which acts as a horizon for a suitably defined accelerated observer, must have an entropy proportional to its area. After providing a…

General Relativity and Quantum Cosmology · Physics 2011-05-05 T. Padmanabhan

We show that the concept of entropy and the dynamics of gravitation provide the linchpin in a unified scheme to understand the physics of black hole computers, space-time foam, dark energy, dark matter and the phenomenon of turbulence. We…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Y. Jack Ng

We derive a formula for the nonequilibrium entropy of a classical stochastic field in terms of correlation functions of this field. The formalism is then applied to define the entropy of gravitational perturbations (both gravitational waves…

General Relativity and Quantum Cosmology · Physics 2009-10-22 R. Brandenberger , T. Prokopec , V. Mukhanov

We propose a thermodynamically motivated measure of gravitational entropy based on the Bel-Robinson tensor, which has a natural interpretation as the effective super-energy-momentum tensor of free gravitational fields. The specific form of…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Timothy Clifton , George F R Ellis , Reza Tavakol

In this work we investigate the thermodynamic properties of conformal gravity in four dimensions. We compute the \emph{area(or entropy) functional} relation for this black hole. We consider both de-Sitter (dS) and anti de-Sitter (AdS)…

General Relativity and Quantum Cosmology · Physics 2017-05-02 Parthapratim Pradhan

In the context of averaging an inhomogeneous cosmological model, we propose a natural measure identical to the Kullback-Leibler relative information entropy, which expresses the distinguishability of the local inhomogeneous density field…

General Relativity and Quantum Cosmology · Physics 2011-07-28 Masaaki Morita , Thomas Buchert , Akio Hosoya , Nan Li

The spontaneous violation of Lorentz and diffeomorphism invariance in a phase near the big bang lowers the entropy, allowing for an arrow of time and the second law of thermodynamics. The spontaneous symmetry breaking leads to…

General Relativity and Quantum Cosmology · Physics 2016-03-08 J. W. Moffat

We provide a formulation and proof of the gravitational entropy bound. We use a recently given framework which expresses the measurable quantities of a quantum theory as a weighted sum over paths in the theory's phase space. If this…

High Energy Physics - Theory · Physics 2024-12-04 Artem Averin

We apply a recent proposal to define "gravitational entropy" to the expansion of cosmic voids within the framework of non-perturbative General Relativity. By considering CDM void configurations compatible with basic observational…

General Relativity and Quantum Cosmology · Physics 2014-08-15 Roberto A. Sussman

The log-periodic equation for the entropy $S = - (k/a) \sum_{i=1}^{N} p_{i} \sin(a \ln p_{i})$, based on the forgotten Sharma-Taneja entropy measure, is studied for the first time with $N$ the total number of system states and $p_{i}$ the…

Data Analysis, Statistics and Probability · Physics 2014-01-21 E. Canessa

We propose a method to associate a differentiable Riemannian manifold to a generic many degrees of freedom discrete system which is not described by a Hamiltonian function. Then, in analogy with classical Statistical Mechanics, we introduce…

Mathematical Physics · Physics 2015-10-08 Roberto Franzosi , Domenico Felice , Stefano Mancini , Marco Pettini

It has been pointed out by Bekenstein and Mayo that the behavior of the Black hole's entropy or information flow is similar to that through one-dimensional channel. Here I analyse the same issue with the use of gravitational anomalies. The…

General Relativity and Quantum Cosmology · Physics 2015-12-18 Bibhas Ranjan Majhi

We show that under certain technical assumptions, including the existence of a constant mean curvature (CMC) slice and strict positivity of the scalar field, general relativity conformally coupled to a scalar field can be quantised on a…

General Relativity and Quantum Cosmology · Physics 2013-04-25 Norbert Bodendorfer , Alexander Stottmeister , Andreas Thurn

One of the few accepted dynamical foundations of non-additive "non-extensive") statistical mechanics is that the choice of the appropriate entropy functional describing a system with many degrees of freedom should reflect the rate of growth…

Statistical Mechanics · Physics 2017-09-22 Nikolaos Kalogeropoulos

We compute the gravitational entropy of 'spherical Rindler space', a time-dependent, spherically symmetric generalization of ordinary Rindler space, defined with reference to a family of observers traveling along non-parallel, accelerated…

High Energy Physics - Theory · Physics 2013-11-06 Vijay Balasubramanian , Bartlomiej Czech , Borun D. Chowdhury , Jan de Boer

In classical Hamiltonian theories, entropy may be understood either as a statistical property of canonical systems, or as a mechanical property, that is, as a monotonic function of the phase space along trajectories. In classical mechanics,…

General Relativity and Quantum Cosmology · Physics 2016-10-14 Marius Oltean , Luca Bonetti , Alessandro D. A. M. Spallicci , Carlos F. Sopuerta

We suggest a new explanation for the observed large scale flatness, homogeneity and isotropy of the universe. The basic ingredients are elementary and well-known, namely Einstein's theory of gravity and Hawking's method of computing…

High Energy Physics - Theory · Physics 2022-01-20 Neil Turok , Latham Boyle
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