Results 241 to 250 of about 7,599,029 (258)

Possible solution to the cosmological-constant problem

Physical Review Letters, 1990
Summary: Classically the unimodular theory of gravity with a constrained determinant \(g_ {\mu\nu}\) is equivalent to general relativity augmented by an arbitrary cosmological constant \(\Lambda\) which arises as an integration constant. At the quantum level we argue that an integration over \(\Lambda\) should be included in the Euclidean path integral
Ng, Y. Jack, van Dam, H.
openaire   +2 more sources

The Cosmological Constant Problems

2001
The old cosmological constant problem is to understand why the vacuum energy is so small; the new problem is to understand why it is comparable to the present mass density. Several approaches to these problems are reviewed. Quintessence does not help with either; anthropic considerations offer a possibility of solving both.
openaire   +1 more source

ON THE COSMOLOGICAL CONSTANT AND THE COSMIC COINCIDENCE PROBLEM

International Journal of Modern Physics A, 2002
According to a recently proposed idea the indirectly observed negative pressure of our present universe might be explained by the trace anomaly of quantum chromo-dynamics (QCD) as a non-perturbative effect of quantum fields in curved space-times. Examining some of the consequences of the proposed mechanism for the cosmic evolution yields no apparent ...
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A new approach to the "cosmological constant" problem

1996
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Capozziello, Salvatore, de Ritis, Ruggiero, Marino, Alma Angela   +2 more
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Anthropic Approach to the Cosmological Constant Problems

International Journal of Theoretical Physics, 2003
The notion ``anthropic principle'' is used for decades already for a large number of theories which have as their common property: They make use of the fact that an observation can be done only if an observer exists. In cosmology, this means, that one ``explains'' the initial conditions near the ``big bang'' by the additional condition that at present,
openaire   +2 more sources

Bootstrapped Newtonian Cosmology and the Cosmological Constant Problem

Symmetry, 2021
Roberto Casadio, Andrea Giusti
exaly  

The Cosmological Constant

Living Reviews in Relativity, 2001
Sean M. Carroll
exaly  

IS THE COSMOLOGICAL CONSTANT A PROBLEM ?

The Tenth Marcel Grossmann Meeting, 2006
openaire   +1 more source

Categorizing Different Approaches to the Cosmological Constant Problem

Foundations of Physics, 2006
Stefan Nobbenhuis
exaly  

A Solution to the Cosmological Constant Problem in Two Time Dimensions ()

Journal of High Energy Physics Gravitation and Cosmology, 2020
Christoph Köhn
exaly