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The cosmological constant problem [PDF]

open access: yesReviews of Modern Physics, 1989
A review of the cosmological term problem is presented. Baby universe model and the compensating field model are discussed. The importance of more accurate data on the Hubble constant and the Universe age is stressed.
Steven Weinberg
exaly   +4 more sources

The cosmological constant is back [PDF]

open access: yesGeneral Relativity and Gravitation, 1995
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 value for the cosmological constant corresponds to a very tiny vacuum energy density.
Lawrence M Krauss, Michael S Turner
exaly   +4 more sources

Relaxation of the cosmological constant [PDF]

open access: yesPhysical Review D, 2019
We present a model that naturally tunes a large positive cosmological constant to a small cosmological constant. A slowly rolling scalar field decreases the cosmological constant to a small negative value, causing the universe to contract, thus reheating it. An expanding universe with a small positive cosmological constant can be obtained, respectively,
David E. Kaplan, Peter W. Graham
exaly   +3 more sources
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The Cosmological Constants

Nature, 1937
THE fundamental constants of physics, such as c the velocity of light, h Planck's constant, e the charge and m mass of the electron, and so on, provide for us a set of absolute units for measurement of distance, time, mass, etc. There are, however, more of these constants than are necessary for this purpose, with the result that certain dimensionless ...
openaire   +2 more sources

The cosmological constant and cosmological change

Physics Today, 1977
Is the Universe of infinite extent, or is it a finite system? Will it expand forever, or will it reach some maximum size before turning and collapsing upon itself like an inverse Big Bang? Just a few years ago, models of the conventional Friedman types were showing consistent, albeit tentative, evidence for an open, ever-expanding Universe. Since then,
openaire   +1 more source

ON THE COSMOLOGICAL CONSTANT AS A CONSTANT OF INTEGRATION

Modern Physics Letters A, 1991
The possibilities to construct a modification of General Relativity (MGR), where the cosmological constant appears as a constant of integration are considered. A class of new constraints on the metric is found, such that their inclusion in the Hilbert–Einstein action before its variation leads to MGR.
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ANOTHER “COSMOLOGICAL” CONSTANT

International Journal of Modern Physics A, 1992
Capovilla, Jacobson and Dell have found a one-parameter family of field equations which coincides with Einstein’s equations when the parameter is set to zero. The basic variable is an SO(3) vector potential. For generic values of the parameter, we show that the solutions of the field equations may be interpreted in terms of Riemannian geometry.
Bengtsson, Ingemar, Peldán, Peter
openaire   +2 more sources

EFFECTIVE COSMOLOGICAL CONSTANT IN BRANE COSMOLOGY

International Journal of Modern Physics D, 2006
We consider a brane-world of co-dimension one without reflection symmetry. Through it, we give a possible explanation of the great discrepancy between the vacuum energy and the observed cosmological constant without contradiction to the knowledge we have about our Universe. We also show the gravity observed will be standard four-dimensional gravity as
Hu, Sen, Wang, Jing-Rong
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THE COSMOLOGICAL CONSTANT PROBLEM

International Journal of Modern Physics D, 1992
The cosmological constant is a macroscopic parameter which controls the large-scale structure of the Universe. All observations to date have shown that it is very small. However, our modern microscopic theory of particle physics and gravity suggests that the cosmological constant should be very large.
openaire   +1 more source

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