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The quantum field theory prediction of the cosmological constant is 120 orders of magnitude higher than the observed value. This is known as the cosmological constant problem. Here, we deal with the cosmological constant as a scalar field…

High Energy Physics - Theory · Physics 2010-11-29 Nicolas Avilan V. , Jose Rolando Roldan

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

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

With the basic cosmological relations that agree with the recent observations, simple expressions are suggested concerning the value of cosmological constant($\Lambda$). A large contribution of quantum vacuum to the energy momentum tensor…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ishwaree P. Neupane

Astrophysical bounds on the cosmological constant are examined for spherically symmetric bodies. Similar limits emerge from hydrostatical and gravitational equilibrium and the validity of the Newtonian limit. It is argued that the bound…

General Relativity and Quantum Cosmology · Physics 2007-08-27 Andres Balaguera-Antolinez , Christian G. Boehmer , Marek Nowakowski

Recent results indicate the presence of a cosmological constant (or related dark energy) in the universe. It has been conjectured recently that the interaction parameters of physical theories may be dependant on the size parameter of the…

Astrophysics · Physics 2007-05-23 N. Panchapakesan

We observe that the errors on the Hubble constant $H_0$, a universal parameter in any FLRW cosmology, can be larger in specific cosmological models than Gaussian Processes (GP) data reconstruction. We comment on the prior mean function and…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-09 E. Ó Colgáin , M. M. Sheikh-Jabbari

The present discussion contribution is some remarks concerning and review of the proposal by one of us (C. Balazs) to explain the cosmological constant by a/the principle of entropy. Used without further comment this principle of entropy…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-26 H. B. Nielsen , C. Balazs

The usage of the anthropic principle in modern cosmology is reviewed. It is argued that its recent use to explain the observedvalues of cosmological parameters as most probable values for an ensemble of universes, is not justified. However,…

Astrophysics · Physics 2016-11-23 Berndt Müller

Based on our previous attempt, we propose a better way to understand a small but nonzero cosmological constant, as indicated by a number of recent observational studies. We re-examine the assumptions of our model of two scalar fields,…

General Relativity and Quantum Cosmology · Physics 2011-05-23 Yasunori Fujii

A mathematical model of the Universe evolution, based on asymmetric doublet of classical and phantom dcalar Higgs fields with a kinetic connection between the components, has been constructed and studied. A detailed qualitative analysis was…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Yu. G. Ignat'ev , I. A. Kokh

This is a review article for The Review of Particle Physics 2006 (aka the Particle Data Book). It forms a compact review of knowledge of the cosmological parameters as at May 2006. Topics included are Parametrizing the Universe; Extensions…

Astrophysics · Physics 2007-05-23 Ofer Lahav , Andrew R Liddle

We construct a cosmological toy model in which a step-function ``cosmological constant'' is taken into consideration beside ordinary matter. We assume that $\Lambda$ takes two values depending on the epoch, and matter goes from a radiation…

Astrophysics · Physics 2008-11-26 Salvatore Capozziello , Ruggiero de Ritis , Alma Angela Marino

In this paper we discuss a possible cosmological time evolution of fundamental constants from the theoretical and experimental point of views. On the theoretical side, we explain that such a cosmological time evolution is actually something…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Xavier Calmet , Matthias Keller

There has been significant recent progress in observational cosmology. This, in turn, has provided an unprecedented picture of the early universe and its evolution. In this review I will present a (biased) view of how one can use these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Raul Jimenez

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

Cosmology contributes a good deal to the investigation of variation of fundamental physical constants. High resolution data is available and allows for detailed analysis over cosmological distances and a multitude of methods were developed.…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-28 M. Wendt , D. Reimers , P. Molaro

We are at a specific period of modern cosmology, during which the large increase of the amount of data leads to the idea that the determination of cosmological parameters has been achieved with a rather good precision. There is a large…

Astrophysics · Physics 2017-08-23 A. Blanchard

The cosmological constant problem is explained by a theory based on the discrete space-time hypothesis. The calculated cosmological constant value is of the order of 10^-52[m]^-2 or equivalent to about 0.7 of the critical mass density. It…

Astrophysics · Physics 2007-05-23 H. M. Mok

Various models are under consideration with metric type flat FRW whose energy-momentum tensor is described by a perfect fluid whose generic equation state and taking into account the conservation principle, but considering some of the…

General Physics · Physics 2007-05-23 J. A. Belinchon