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The cosmological constant problem is a fundamental issue that has puzzled researchers in the fields of theoretical physics and cosmology for a long time. It arises from the discrepancy between the observed value of the cosmological constant…

General Relativity and Quantum Cosmology · Physics 2024-01-10 Alexander I Nesterov

For a universe presently dominated by static or dynamic vacuum energy, cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of vacuum energy to clustered…

Astrophysics · Physics 2016-11-03 Sidney Bludman

The accelerating expansion of the Universe points to a small positive value for the cosmological constant or vacuum energy density. We discuss recent ideas that the cosmological constant plus LHC results might hint at critical phenomena…

High Energy Physics - Phenomenology · Physics 2015-07-09 Steven D. Bass

Within thermodynamic models of gravity, where the universe is considered as a finite ensemble of quantum particles, cosmological constant in the Einstein's equations appears as a constant of integration. Then it can be bounded using…

General Physics · Physics 2018-05-15 Merab Gogberashvili , Ucha Chutkerashvili

We use general arguments to examine the energy scales for which a quantum coherent description of gravitating quantum energy units is necessary. The cosmological dark energy density is expected to decouple from the Friedman-Lemaitre energy…

Astrophysics · Physics 2007-05-23 James V. Lindesay , H. Pierre Noyes

Within the framework of the minimum quadratic Poincare gauge theory of gravity in the Riemann-Cartan spacetime we study the influence of gravitational vacuum energy density (a cosmological constant) on the dynamics of various gravitating…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Nguyen Hong Chuong , Nguyen Van Hoang

We explore the extended framework of the generalized quantum mechanics and discuss various aspects of neighborhood in the construction of space in search of origin of cosmological constant. We propose to expand definition of the volume of…

General Physics · Physics 2009-01-09 Aalok Pandya

We consider a possibility that the cosmological constant may not be a constant, but a free thermodynamical variable. To this end we construct a microscopic model of a spacelike two-sphere just inside of the cosmological horizon of the de…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Jarmo Mäkelä

The Cosmological Constant Problem emerges when Quantum Field Theory is applied to the gravitational theory, due to the enormous magnitude of the induced energy of the vacuum. The unique known solution of this problem involves an extremely…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ilya L. Shapiro , Joan Sola

In this work we suggest a simple model of the cosmological constant as the coefficient of the quantum tunneling of vacuum fluctuations (with wave length larger than Planck length) at tiny, boundary spherical shell of the universe (with…

General Relativity and Quantum Cosmology · Physics 2009-01-06 Vladan Pankovic , Miodrag krmar , Sima Ciganovic

For a flat universe presently dominated by smooth energy, either cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of smooth energy to matter energy…

Astrophysics · Physics 2009-10-31 Sidney Bludman , Matts Roos

The cosmological constant is treated as a thermodynamical parameter in the framework of two-dimensional dilaton gravity. We find that the cosmological constant behaves as a U(1) charge with a confining potential, and that such potentials…

High Energy Physics - Theory · Physics 2014-08-20 Daniel Grumiller , Robert McNees , Jakob Salzer

The cosmological constant $\Lambda$ is a measure of the energy density of the vacuum. Therefore properties of the energy of the system in the metastable vacuum state reflect properties of $\Lambda = \Lambda(t)$. We analyze properties of the…

General Relativity and Quantum Cosmology · Physics 2022-03-23 Krzysztof Urbanowski

Standard cosmology has long been plagued by a number of persistent problems. The origin of the apparent acceleration of the cosmic expansion remains enigmatic. The cosmological constant has been reintroduced as a free parameter with a value…

General Physics · Physics 2023-02-28 Jan O. Stenflo

In this essay we offer a comprehensible overview of the gravitational aether scenario. This is a possible extension of Einstein's theory of relativity to the quantum regime via an effective approach. Quantization of gravity usually faces…

General Relativity and Quantum Cosmology · Physics 2017-05-19 Michael Florian Wondrak

The cosmological constant, 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, despite its…

Astrophysics · Physics 2008-11-26 S. Carneiro , M. A. Dantas , C. Pigozzo , J. S. Alcaniz

The accelerating expansion of the Universe points to a small positive vacuum energy density and negative vacuum pressure. A strong candidate is the cosmological constant in Einstein's equations of General Relativity. The vacuum dark energy…

High Energy Physics - Phenomenology · Physics 2012-10-12 Steven D. Bass

Einstein introduced Cosmological Constant in his field equations in an ad hoc manner. Cosmological constant plays the role of vacuum energy of the universe which is responsible for the accelerating expansion of the universe. To give…

General Physics · Physics 2015-06-15 B. Raychaudhuri , F. Rahaman , M. Kalam

We consider further consequences of recently [1] revealed role of cosmological constant \Lambda as of a physical constant, along with the gravitational one to define the gravity i.e. the General Relativity and its low-energy limit. We now…

General Physics · Physics 2019-03-13 V. G. Gurzadyan , A. Stepanian

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…

Astrophysics · Physics 2007-05-23 Steven Weinberg
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