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The paper deals with the scale discrepancy between the observed vacuum energy in cosmology and the theoretical quantum vacuum energy (cosmological constant problem). Here, we demonstrate that Einstein's equation and an analogy to particle…

General Physics · Physics 2019-02-08 Christian Henke

This article presents a simple model that reproduces key concepts of modern cosmology within the framework of special relativity, at a level that is suitable for an undergraduate or high school setting. The model includes cosmic expansion…

General Relativity and Quantum Cosmology · Physics 2019-01-14 Markus Pössel

We consider Friedmann-Lema\^{\i}tre-Robertson-Walker flat cosmological models in the framework of general Jordan frame scalar-tensor theories of gravity with arbitrary coupling function and potential. For the era when the cosmological…

General Relativity and Quantum Cosmology · Physics 2011-01-06 Laur Järv , Piret Kuusk , Margus Saal

The Cosmological General Relativity (CGR) of Carmeli, a 5-dimensional (5-D) theory of time, space and velocity, predicts the existence of an acceleration a_0 = c / tau due to the expansion of the universe, where c is the speed of light in…

General Physics · Physics 2015-06-04 Firmin J. Oliveira

An accelerating flat universe with a variable cosmological term is obtained in the Robertson-Walker metric. The variable cosmological term is defined by the correction terms of the metric tensor field. Simple solutions of the scale factor…

Astrophysics · Physics 2015-06-24 Takao Fukui

A generalized scalar-tensor theory is investigated whose cosmological term depends on both a scalar field and its time derivative. A correspondence with solutions of five-dimensional Space-Time-Matter theory is noted. Analytic solutions are…

General Relativity and Quantum Cosmology · Physics 2009-11-07 T. Fukui , J. M. Overduin

The acceleration parameter defined through the local volume expansion is negative for a pressureless, irrotational fluid with positive energy density. In the presence of inhomogeneities or anisotropies the volume expansion rate results from…

In this paper, dark energy is modelled via a spherically symmetric quintessence scalar field $\varphi$, the dynamics of which are found to be analogous to a pendulum. This is due to a driving axion potential $V(\left|\varphi\right|)$, whose…

General Relativity and Quantum Cosmology · Physics 2014-05-30 M. P. Pierpoint , F. V. Kusmartsev

The concordance model of cosmology suffers from the major theoretical problems surrounding the observed value and recent emergence of a cosmological constant. In this paper we present a novel approach, which explains more naturally its…

General Relativity and Quantum Cosmology · Physics 2020-03-18 J. Lorca Espiro , M. Le Delliou

We study a $(4+D)$-dimensional Kaluza-Klein cosmology with a Robertson-Walker type metric having two scale factors $a$ and $R$, corresponding to $D$-dimensional internal space and 4-dimensional universe, respectively. By introducing an…

General Relativity and Quantum Cosmology · Physics 2009-02-12 F. Darabi

We consider flat Friedmann-Lema\^{\i}tre-Robertson-Walker cosmological models in the framework of general scalar-tensor theories of gravity with arbitrary coupling functions, set in the Jordan frame, in the cosmological epoch when the…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Laur Järv , Piret Kuusk , Margus Saal

The common nature of dark matter and dark energy is argued in [1] based on the approach that the cosmological constant \Lambda enters the weak-field General Relativity following from Newton theorem on the "sphere-point mass" equivalency…

General Physics · Physics 2019-02-27 V. G. Gurzadyan , A. Stepanian

Carmeli's 5D brane cosmology has been applied to the expanding accelerating universe and it has been found that the distance redshift relation will fit the data of the high-z supernova teams without the need for dark matter. Also the vacuum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. G. Hartnett

A complete analysis of the dynamics of the Hu-Sawicki modification to General Relativity is presented. In particular, the full phase-space is given for the case in which the model parameters are taken to be n=1, c1=1, and several stable de…

General Relativity and Quantum Cosmology · Physics 2015-11-03 Sulona Kandhai , Peter K. S. Dunsby

Cosmological models with two interacting fluids, each satisfying the strong energy condition, are studied in the framework of classical General Relativity. If the interactions are phenomenologically described by a power law in the scale…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Nelson Pinto-Neto , Bernardo M. O. Fraga

The theoretical framework of cosmology is mainly defined by gravity, of which general relativity is the current model. Recent tests of general relativity within the \Lambda Cold Dark Matter (CDM) model have found a concordance between…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-30 Radoslaw Wojtak , Steen H. Hansen , Jens Hjorth

The cosmological constant problem represents a profound conflict between quantum field theory and general relativity. Unimodular gravity offers a compelling starting point by de-gravitating the vacuum energy of the Standard Model, but this…

High Energy Physics - Phenomenology · Physics 2025-11-18 David E. Kaplan , Surjeet Rajendran

The velocity of the Hubble expansion has been added to General Relativity by Moshe Carmeli and this resulted in new equations of motion for the expanding universe. For the first time the observational magnitude-redshift data derived from…

Astrophysics · Physics 2007-05-23 John G. Hartnett

A general-relativistic theory of cosmology, the dynamical variables of which are those of Hubble's, namely distances and redshifts, is presented. The theory describes the universe as having a three-phase evolution with a decelerating…

Astrophysics · Physics 2007-05-23 S. Behar , M. Carmeli

The standard model of elementary particle physics and the theory of general relativity can be extended by the introduction of a vacuum variable which is responsible for the near vanishing of the present cosmological constant (vacuum energy…

High Energy Physics - Theory · Physics 2014-11-20 F. R. Klinkhamer , G. E. Volovik