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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

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

We derive strong observational limits on any possible large-scale spatial variation in the values of physical 'constants' whose space-time evolution is driven by a scalar field. The limits are imposed by the isotropy of the microwave…

Astrophysics · Physics 2009-11-10 John D. Barrow

The Cosmic Defect theory has been confronted with four observational constraints: primordial nuclear species abundances emerging from the big bang nucleosynthesis; large scale structure formation in the universe; cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 N. Radicella , M. Sereno , A. Tartaglia

New Hubble Space Telescope observations of Cepheid variable stars in the nearby galaxy M96 give a distance to the host galaxy group, Leo-I, of 11.6+/-0.8 Mpc. This value, used in conjunction with several reliable secondary indicators of…

Astrophysics · Physics 2009-10-28 N. R. Tanvir , T. Shanks , H. C. Ferguson , D. R. T. Robinson

The cosmological constant ($\Lambda$), i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However,…

Astrophysics · Physics 2007-05-23 J. S. Alcaniz , H. Stefancic

We phenomenologically put local constraints on the rotation of distant masses by using the planets of the solar system. First, we analytically compute the orbital secular precessions induced on the motion of a test particle about a massive…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Lorenzo Iorio

In a recent paper (Vigoureux et al. Int. J. Theor. Phys. 47:928, 2007) it has been suggested that the velocity of light and the expansion of the universe are two aspects of one single concept connecting space and time in the expanding…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-22 David Viennot , Jean-Marie Vigoureux

I limelight and review a potentially crucial aspect of MOND: The near equality of the MOND acceleration constant, $a_0$ -- as deduced from local, galactic phenomena -- and cosmological parameters. To wit, $a_0\sim c H_0\sim…

Astrophysics of Galaxies · Physics 2020-01-28 Mordehai Milgrom

Next year we will celebrate 100 years of the cosmological term, $\Lambda$, in Einstein's gravitational field equations, also 50 years since the cosmological constant problem was first formulated by Zeldovich, and almost about two decades of…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Joan Sola

A static non-singular 10-dimensional closed Friedmann universe of Planck size, filled with a perfect fluid with an equation of state with w = -2/3, can arise spontaneously by a quantum fluctuation from nothing in 11-dimensional spacetime. A…

General Relativity and Quantum Cosmology · Physics 2009-11-11 T. R. Mongan

A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The…

High Energy Physics - Theory · Physics 2007-05-23 Stephon Alexander , Manasse Mbonye , John Moffat

The observed value of the cosmological constant poses large theoretical problems. We find that topology of the Universe provides a natural source for it. Restricting dynamically an Einstein-Cartan gravity to General Relativity in our…

General Relativity and Quantum Cosmology · Physics 2020-06-16 M. Le Delliou , J. Lorca Espiro

The Hubble constant $H_0$, the current expansion rate of the universe, is one of the most important parameters in cosmology. The cosmic expansion regulates the mutually approaching motion of a pair of celestial objects due to their gravity.…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-30 Wangzheng Zhang , Ming-chung Chu , Shihong Liao , Shek Yeung , Hui-Jie Hu

We investigate the cosmological test recently proposed by B. Fort, Y. Mellier and M. Dantel-Fort (FMD), where the observed location of the critical line in gravitational lensing is used to determine the cosmological parameters, $\Omega$ and…

Astrophysics · Physics 2009-10-28 Hideki Asada

The uncertainty on measurements, given by the Heisenberg principle, is a quantum concept usually not taken into account in General Relativity. From a cosmological point of view, several authors wonder how such a principle can be reconciled…

General Relativity and Quantum Cosmology · Physics 2020-08-26 Salvatore Capozziello , Micol Benetti , Alessandro D. A. M Spallicci

In this paper we use and extend the results present in \cite{1,2,3,4} and in particular in \cite{4} to obtain a statistical description of the cosmological constant in a cosmological de Sitter universe in terms of massless excitations with…

General Relativity and Quantum Cosmology · Physics 2018-10-18 Stefano Viaggiu

I start by defining the cosmological parameters $H_0, \Omega_m$ and $\Omega_\Lambda$. Then I show how the age of the universe depends on them, followed by the evolution of the scale parameter of the universe for various values of the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Palash B. Pal

The Hubble constant sets the size and age of the Universe, and, together with independent determinations of the age, provides a consistency check of the standard cosmology. The Hubble constant also provides an important test of our most…

Astrophysics · Physics 2007-05-23 Michael S. Turner

A diverse set of observations now compellingly suggest that Universe possesses a nonzero cosmological constant. In the context of quantum-field theory a cosmological constant corresponds to the energy density of the vacuum, and the wanted…

Astrophysics · Physics 2014-10-13 Lawrence M. Krauss , Michael S. Turner