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The cosmological constant (lambda) of general relativity is a natural consequence of embedding Einstein's theory in a five-dimensional theory of the type needed for unification. The exact 5D solution for lambda less than 0 shows waves in…

General Relativity and Quantum Cosmology · Physics 2014-11-04 Paul S. Wesson

Lord Kelvin believed that the electromagnetic aether must also generate gravity. Presently, we have no methods to determine the density of the electromagnetic aether, or we say the $\Omega(1)$ substratum. Thus, we also suppose that vacuum…

General Physics · Physics 2022-09-22 Xiao-Song Wang

The quantum field theoretic prediction for the vacuum energy density leads to a value for the effective cosmological constant that is incorrect by between 60 to 120 orders of magnitude. We review an old proposal of replacing Einstein's…

General Relativity and Quantum Cosmology · Physics 2011-10-24 George F. R. Ellis , Henk van Elst , Jeff Murugan , Jean-Philippe Uzan

We discuss the cosmological constant problem, at the minisuperspace level, within the framework of the so-called normalized general relativity (NGR). We prove that the Universe cannot be closed, and reassure that the accompanying…

General Relativity and Quantum Cosmology · Physics 2014-02-03 Aharon Davidson , Shimon Rubin

In this paper we continue the investigations in \cite{1} concerning the origin of the cosmological constant. First of all, we generalise the results in \cite{1,2} by considering a continuum approximation for a radiation field in a…

General Relativity and Quantum Cosmology · Physics 2019-08-23 Stefano Viaggiu

Cosmological constant can always be considered as the on-shell value of a top form in gravitational theories. The top form is field strength of a gauge field, and the theory enjoys a gauge symmetry. We show that cosmological constant is the…

General Relativity and Quantum Cosmology · Physics 2018-05-29 Dmitry Chernyavsky , Kamal Hajian

We are at a specific period of modern cosmology, during which the large increase of the amount of data leads to the idea that the determination of cosmological parameters has been achieved with a rather good precision. There is a large…

Astrophysics · Physics 2017-08-23 A. Blanchard

Persistent tensions in the $\Lambda$CDM cosmological model underline the importance of tests of its basic assumptions. One such potential test arises from the fact that the surface of zero expansion around the collapsing object with…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-21 Jan J. Ostrowski , Ismael Delgado Gaspar

We examine a simple theoretical model to estimate (by fine tuning condition) the value of the cosmological constant. We assume, in analogy with holographic principle, that cosmological constant, like classical surface tension coefficient in…

Astrophysics · Physics 2008-01-21 V. Pankovic , S. Ciganovic , J. Ivanovic , R. Glavatovic , P. Grujic

The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in…

General Relativity and Quantum Cosmology · Physics 2016-11-14 Cláudio Nassif

We demonstrate that, in the context of the $\Lambda$CDM model, it is in principle possible to measure the value of the cosmological constant by tracing, across cosmic time, the evolution of the turnaround radius of cosmic structures. The…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-18 Dimitrios Tanoglidis , Vasiliki Pavlidou , Theodore Tomaras

In this year, in which we celebrate 100 years of the cosmological term, $\Lambda$, in Einstein's gravitational field equations, we are still facing the crucial question whether $\Lambda$ is truly a fundamental constant or a mildly evolving…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-27 Joan Sola , Adria Gomez-Valent , Javier de Cruz Perez

We discuss several issues related to a recent proposal for defining classical spatial averages to be used in the so-called cosmological backreaction problem. In the large averaging-volume limit all gauge dependence disappears and different…

General Relativity and Quantum Cosmology · Physics 2011-07-14 Giovanni Marozzi

A mechanism for suppressing the cosmological constant is described, using a superconducting analogy in which fermions coupled to gravitons are in an unstable false vauum. The coupling of the fermions to gravitons and a screened attractive…

High Energy Physics - Theory · Physics 2009-11-10 J. W. Moffat

We point out that for a large class of universes, holography implies that the most probable value of the cosmological constant is zero. In four spacetime dimensions, the probability distribution takes the Baum-Hawking form,…

High Energy Physics - Theory · Physics 2009-07-09 Petr Horava , Djordje Minic

How much can we know about our Universe? All of our observations are restricted to a finite volume, and therefore our estimates of presumably global cosmological parameters are necessarily based on incomplete information. Even assuming that…

Astrophysics · Physics 2008-04-11 T. P. Waterhouse , J. P. Zibin

Within conventional big bang cosmology, it has proven to be very difficult to understand why today's cosmological constant is so small. In this paper, we show that a cyclic model of the universe can naturally incorporate a dynamical…

Astrophysics · Physics 2009-09-01 Paul J. Steinhardt , Neil Turok

New, large, ground and space telescopes are contributing to an exciting and rapid period of growth in observational cosmology. The subject is now far from its earlier days of being data-starved and unconstrained, and new data are fueling a…

Astrophysics · Physics 2009-11-07 Wendy L. Freedman

The Hamiltonian structure of general relativity provides a natural canonical measure on the space of all classical universes, i.e., the multiverse. We review this construction and show how one can visualize the measure in terms of a…

High Energy Physics - Theory · Physics 2008-11-26 G. W. Gibbons , Neil Turok

Everpresent $\Lambda$ is a cosmological scenario in which the observed cosmological "constant" $\Lambda$ fluctuates between positive and negative values with a vanishing mean, and with a magnitude comparable to the critical density at any…

General Relativity and Quantum Cosmology · Physics 2018-10-17 Nosiphiwo Zwane , Niayesh Afshordi , Rafael D. Sorkin
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