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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

The experimental data, as well as theoretical considerations allow (and, in some cases, require) the Universe at present to rest in a false vacuum, whose approximate stability imposes constraints on the model parameters. Under very general…

High Energy Physics - Phenomenology · Physics 2014-11-17 Alexander Kusenko , Paul Langacker

Cosmology struggles with the theoretical problems generated by the observed value and recent emergence of a cosmological constant, in the standard model of cosmology, i.e. the concordance model. We propose to provide a more natural…

General Relativity and Quantum Cosmology · Physics 2019-05-08 J. Lorca Espiro , Morgan Le Delliou

We discuss from the condensed-matter point of view the recent idea that the Poisson fluctuations of cosmological constant about zero could be a source of the observed dark energy. We argue that the thermodynamic fluctuations of Lambda are…

General Relativity and Quantum Cosmology · Physics 2009-11-10 G. E. Volovik

The cosmological constant presents one of the most fascinating and confounding problems in physics. A straightforward, seemingly robust prediction of quantum mechanics and general relativity is that the vacuum energy gravitates. Therefore,…

High Energy Physics - Theory · Physics 2023-08-16 Suman Kumar Kundu , Arnab Pradhan , Carl Rosenzweig

A new vision of the beginning and expansion of our universe has produced a solution to the vacuum energy problem (also known as "cosmological constant problem"). A new dynamic of cellular spaces and a discrete time has space being produced…

Astrophysics · Physics 2007-05-23 Charles B. Leffert

In cosmology, the cosmic curvature $K$ and the cosmological constant $\Lambda$ are two important parameters, and the values have strong influence on the behavior of the universe. In the context of normal cosmology, under the ordinary…

General Relativity and Quantum Cosmology · Physics 2017-08-11 Ying-Qiu Gu

Standard quantum field theory arguments predict an enormous cosmological constant. But what would this mean observationally? For a homogeneous universe the answer is clear, but if the universe is inhomogeneous at the Planck scale, the…

General Relativity and Quantum Cosmology · Physics 2025-10-30 Steven Carlip

Dynamical dark energy (DE) has been proposed to explain various aspects of the cosmological constant (CC) problem(s). For example, it is very difficult to accept that a strictly constant Lambda-term constitutes the ultimate explanation for…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Javier Grande , Joan Sola , Hrvoje Stefancic

In this work a satisfactory, simple theoretical prediction of the data corresponding to observationally (by fine tuning condition) estimated value of the cosmological constant is given. It is supposed (in conceptually analogy with…

Astrophysics · Physics 2007-12-27 Vladan Pankovic , Simo Ciganovic , Jovan Ivanovic , Rade Glavatovic , Petar Grujic

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

Self tuning is one of the few methods for dynamically cancelling a large cosmological constant and yet giving an accelerating universe. Its drawback is that it tends to screen all sources of energy density, including matter. We develop a…

General Relativity and Quantum Cosmology · Physics 2018-08-01 Stephen Appleby , Eric V. Linder

With cooling of the cosmological plasma during phase transitions in the early Universe vacuum condensates of quantum fields were produced with negative energy density. Probably these condensates have compensated the initial vacuum energy.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Vladimir Burdyuzha

When the cosmological constant of spacetime is derived from the 5D induced-matter theory of gravity, we show that a simple gauge transformation changes it to a variable measure of the vacuum which is infinite at the big bang and decays to…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Bahram Mashhoon , Paul S. Wesson

In the more recent literature on cosmological evolutions of the universe the cosmic vacuum energy has become a non-renouncable ingredient. The cosmological constant $\Lambda$, first invented by Einstein, but later also rejected by him,…

General Relativity and Quantum Cosmology · Physics 2016-10-28 H. J. Fahr , M. Heyl

This contribution reviews recent work on a new approach to the cosmological constant problem, which starts from the macroscopic behavior of a conserved relativistic microscopic variable q. First, the statics of the vacuum energy density is…

General Relativity and Quantum Cosmology · Physics 2008-11-11 F. R. Klinkhamer

The cosmological constant problem is turned around to argue for a new foundational physics postulate underlying a consistent quantum theory of gravity and matter, such as string theory. This postulate is a quantum equivalence principle…

High Energy Physics - Theory · Physics 2008-11-26 Vishnu Jejjala , Djordje Minic

A huge value of cosmological constant characteristic for the particle physics and the inflation of early Universe are inherently related to each other: one can construct a fine-tuned superpotential, which produces a flat potential of…

General Relativity and Quantum Cosmology · Physics 2015-06-03 V. V. Kiselev , S. A. Timofeev

The standard formulation of the cosmological constant problem is based on one critical assumption---the spacetime is homogeneous and isotropic, which is true only on cosmological scales. However, this problem is caused by extremely small…

General Relativity and Quantum Cosmology · Physics 2020-08-05 Qingdi Wang

A new kind of evolution for cyclic models in which the Hubble parameter oscillates and keeps positive has been explored in a specific $f(R,T)$ gravity reconstruction. A singularity-free cyclic universe with negative varying cosmological…

General Relativity and Quantum Cosmology · Physics 2019-02-11 Nasr Ahmed , Sultan Z. Alamri
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