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A cosmology with the growing cosmological term is considered. If there is no exchange of energy between vacuum and matter components, the requirement of general covariance implies the time dependence of the gravitational constant $G$.…

Astrophysics · Physics 2014-10-13 Hrvoje Stefancic

In this paper, it is the first time to construct a complete post-Newtonian (PN) model of a rigid body by means of a new constraint on the mass current density and mass density. In our PN rigid body model most of relations, such as spin…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Chongming Xu , Jin-he Tao , Xuejun Wu

The equations of motion describing all physical systems, except gravity, remain invariant if a constant is added to the Lagrangian. In the conventional approach, gravitational theories break this symmetry exhibited by all other physical…

General Relativity and Quantum Cosmology · Physics 2015-12-22 T. Padmanabhan

In this paper, we analyze the effects of expansion on large scale structure formation in our Universe. We do that by incorporating a cosmological constant term in the gravitational partition function. This gravitational partition function…

General Physics · Physics 2022-07-13 Mir Hameeda , Behnam Pourhassan , Syed Masood , Mir Faizal , Li-Gang Wang , Shohaib Abass

The purpose of this review it to present a renewed perspective of the problem of self-gravitating elastic bodies under spherical symmetry. It is also a companion to the papers [Phys. Rev. D105, 044025 (2022)], [Phys. Rev. D106, L041502…

General Relativity and Quantum Cosmology · Physics 2024-04-05 Artur Alho , José Natário , Paolo Pani , Guilherme Raposo

A holistic view of the cosmological appearance and development of space is obtained by studying space as a spherically closed surface of a 4-sphere in a zero energy balance between motion and gravitation. Such an approach re-establishes…

Astrophysics · Physics 2009-11-13 Tuomo Suntola

Starting with the relativistic Boltzmann equation for a system of particles defined by a distribution function, we have derived the virial relation for a spherical structure within an expanding background in the context of general…

General Relativity and Quantum Cosmology · Physics 2016-02-03 Reza Javadinezhad , Javad T. Firouzjaee , Reza Mansouri

We investigate structure that describes physical data in gravitational systems that is, to one degree or another, independent of the metric and affine structure. We dub such structure surplus structure and seek to incorporate it into our…

History and Philosophy of Physics · Physics 2023-04-11 Kyle Singh , Jenna Van Dyke

Loop quantum gravity and cosmology are reviewed with an emphasis on evaluating the dynamics, rather than constructing it. The three crucial parts of such an analysis are (i) deriving effective equations, (ii) controlling the theory's…

General Relativity and Quantum Cosmology · Physics 2011-01-31 Martin Bojowald

We quantify the physical memory of the cosmic density field using mutual information between $N$-body snapshots at different redshifts, removing a random baseline to isolate gravitational correlations. The shared mutual information rises…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-06 Biswajit Pandey , Anindita Nandi

We develop, in the context of general relativity, the notion of a geoid -- a surface of constant "gravitational potential". In particular, we show how this idea naturally emerges as a specific choice of a previously proposed, more general…

General Relativity and Quantum Cosmology · Physics 2016-06-10 Marius Oltean , Richard J. Epp , Paul L. McGrath , Robert B. Mann

A detailed analysis of dynamics of cosmological models based on $R^{n}$ gravity is presented. We show that the cosmological equations can be written as a first order autonomous system and analyzed using the standard techniques of dynamical…

General Relativity and Quantum Cosmology · Physics 2009-11-10 S. Carloni , P. K. S. Dunsby , S. Capozziello , A. Troisi

I investigate the relativistic mechanics of an extended "cable" in an arbitrary static, spherically symmetric spacetime. Such hypothetical bodies have been proposed as tests of energy and thermodynamics: by lowering objects toward a black…

General Relativity and Quantum Cosmology · Physics 2022-09-05 Colin MacLaurin

Non-linear electrodynamics coupled to general relativity is investigated. In general relativity, it is observed that the expansion of the universe is accelerating if the source of the gravitational field is the non-linear electromagnetic…

General Relativity and Quantum Cosmology · Physics 2018-10-05 Gauranga C. Samanta , Shantanu K. Biswal , Kazuharu Bamba

As the separation between galaxies increases owing to the expansion of the universe, galaxies themselves and smaller bound structures do not grow. An accurate description of the dynamics of cosmic structures requires the full apparatus of…

General Relativity and Quantum Cosmology · Physics 2013-07-23 Nivaldo A. Lemos

The "cosmic triangle" is introduced as a way of representing the past, present, and future status of the universe. Our current location within the cosmic triangle is determined by the answers to three questions: How much matter is in the…

Astrophysics · Physics 2009-09-15 N. Bahcall , J. P. Ostriker , S. Perlmutter , P. J. Steinhardt

There is now strong evidence that the current energy density of the Universe is dominated by dark energy with an equation of state w<-1/3, which is causing accelerated expansion. The build-up of structure within such Universes is subject to…

Astrophysics · Physics 2008-11-26 Will J. Percival

A new type of fluid matter model in general relativity is introduced, in which the fluid particles are subject to velocity diffusion without friction. In order to compensate for the energy gained by the fluid particles due to diffusion, a…

General Relativity and Quantum Cosmology · Physics 2015-06-04 Simone Calogero

In the last century, theoretical and experimental developments have established the General Relativity theory as the most successful theory for describing the gravitational phenomenon. On the other hand, in the last two decades, multiple…

General Relativity and Quantum Cosmology · Physics 2025-02-18 Raja Solanki

Assuming that the relativistic universe is homogeneous and isotropic, we can unambiguously determine its model and physical properties, which correspond with the Einstein general theory of relativity (and with its two special partial…

General Physics · Physics 2010-12-27 Vladimir Skalsky