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We study the quantized Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) model minimally coupled to a free massless scalar field. In a previous paper, \cite{fab2}, solutions of this model were constructed as gaussian superpositions of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 N. Pinto-Neto , E. Sergio Santini

We consider ever-expanding Big Bang models with a cosmological constant, $\Lambda$, and investigate in detail the evolution of the observable part of the universe. We also discuss quintessence models from the same point of view. A new…

Astrophysics · Physics 2009-11-06 Einar H. Gudmundsson , Gunnlaugur Bjornsson

Most of the literature on general relativity over the last century assumes that the cosmological constant $\Lambda$ is zero. However, by now independent observations have led to a consensus that the dynamics of the universe is best…

General Relativity and Quantum Cosmology · Physics 2021-04-02 Abhay Ashtekar

We consider general relativity with a cosmological constant as a perturbative expansion around a completely solvable diffeomorphism invariant field theory. This theory is the $\Lambda\to\infty$ limit of general relativity. This allows an…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Rodolfo Gambini , Jorge Pullin

In `entropic cosmology', instead of a cosmological constant $\Lambda$, an extra driving term is added to the Friedmann equation and the acceleration equation, taking into account the entropy and the temperature on the horizon of the…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-14 Nobuyoshi Komatsu , Shigeo Kimura

We have investigated a cosmological model with variable speed of light (c), gravitational constant (G) and cosmological constant (Lambda). The model is shown to solve the horizon, flatness and monopole problems of the early universe. We…

Astrophysics · Physics 2007-05-23 Arbab I. Arbab

In 2007 Rindler and Ishak showed that, contrary to previous claims, the value of the cosmological constant does have an effect on light deflection by a gravitating object in an expanding universe, modeled by a Schwarzschild-de~Sitter…

General Relativity and Quantum Cosmology · Physics 2018-05-25 Mir Emad Aghili , Brett Bolen , Luca Bombelli

We review current observations of the homogeneous cosmological expansion which, because they measure only kinematic variables, cannot determine the dynamics driving the recent accelerated expansion. The minimal fit to the data, the flat…

Astrophysics · Physics 2015-05-13 Sidney Bludman

In this paper we present the equations of the evolution of the universe in $D$ spatial dimensions, as a generalization of the work of Lima \citep{lima}. We discuss the Friedmann-Robertson-Walker cosmological equations in $D$ spatial…

General Relativity and Quantum Cosmology · Physics 2012-07-09 R. F. L. Holanda , S. H. Pereira

It is observed that one of Einstein-Friedmann's equations has formally the aspect of a Sturm-Liouville problem, and that the cosmological constant, $\Lambda$, plays thereby the role of spectral parameter (what hints to its connection with…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-19 Artyom V. Yurov , Artyom V. Astashenok , E. Elizalde

We investigate the virialization of cosmic structures in the framework of flat FLRW cosmological models, in which the vacuum energy density evolves with time. In particular, our analysis focuses on the study of spherical matter…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 S. Basilakos , M. Plionis , J. Sola

The interpretation of the expanding universe as an expansion of space has recently been challenged. From the geodesic equation in Friedmann universe models and the empty Milne model, we argue that a Newtonian or special relativistic…

Astrophysics · Physics 2009-11-11 Oyvind Gron , Oystein Elgaroy

On the basis of qualitative analysis of the system of differential equations of the standard cosmological model it is shown that in the case of zero cosmological constant this system has a stable center corresponding to zero values of…

General Relativity and Quantum Cosmology · Physics 2016-09-29 Yurii Ignat'ev

The cascade relaxation of a polarized vacuum in the expanding Universe is a chain of evolutionary epochs of decreasing its density with the exit of dominant fields (each in its own time) from the initial zero states to nonzero values, from…

General Relativity and Quantum Cosmology · Physics 2025-06-05 V. N. Lukash , E. V. Mikheeva

Wheeler's conjectured "spacetime foam" -- large quantum fluctuations of spacetime at the Planck scale -- could have important implications for quantum gravity, perhaps even explaining why the cosmological constant seems so small. Here I…

General Relativity and Quantum Cosmology · Physics 2022-01-05 S. Carlip

Several recent papers have suggested that the cosmological constant Lambda directly influences the gravitational deflection of light. We place this problem in a cosmological context, deriving an expression for the linear potentials which…

Astrophysics · Physics 2012-01-16 Fergus Simpson , John A. Peacock , Alan F. Heavens

This paper deals with the cancellation mechanism, which identifies the energy density of space-time expansion in an empty universe with the zero-point energy density and avoids the scale discrepancy with the observed energy density…

General Physics · Physics 2018-06-12 Christian Henke

Recent observations of the Universe have led to a conclusion suppressing an up-to-now supposed deceleration of the Universe caused by attractive gravitational forces. Contrary, there is a renaissance of the cosmological member lambda and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jozef Sima , Miroslav Sukenik

The asymptotic structure of the gravitational field of isolated systems has been analyzed in great detail in the case when the cosmological constant $\Lambda$ is zero. The resulting framework lies at the foundation of research in diverse…

General Relativity and Quantum Cosmology · Physics 2015-10-21 Abhay Ashtekar , Beatrice Bonga , Aruna Kesavan

It has been proposed that the cosmological constant $\Lambda$ might be measured from geometric effects on large-scale structure. A positive vacuum density leads to correlation-function contours which are squashed in the radial direction…

Astrophysics · Physics 2015-06-24 W. E. Ballinger , J. A. Peacock , A. F. Heavens