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The expansion of the observed universe appears to be accelerating. A simple explanation of this phenomenon is provided by the non-vanishing of the cosmological constant in the Einstein equations. Arguments are commonly presented to the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-07 Eugenio Bianchi , Carlo Rovelli

We discuss experiments and observations aimed at testing the possible space-time variability of fundamental physical constants, predicted by the modern theory. Specifically, we consider two of the dimensionless physical parameters which are…

Atomic Physics · Physics 2007-05-23 D. A. Varshalovich , A. Y. Potekhin , A. V. Ivanchik

A brief review of the search for variation of the fine structure constant in quasar absorption spectra is presented. Special consideration is given to the role of atomic calculations in the analysis of the observed data. A range of methods…

Atomic Physics · Physics 2015-05-13 V. A. Dzuba , V. V. Flambaum

We show that a slowly varying Newton's constant, consistent with existing bounds, can potentially explain a host of observations pertaining to gravitational effects or phenomena across distances spanning from planetary to the cosmological,…

General Relativity and Quantum Cosmology · Physics 2024-11-12 Saurya Das , Sourav Sur

The cosmological constant if considered as a fundamental constant, provides an information treatment for gravitation problems, both cosmological and of black holes. The efficiency of that approach is shown via gedanken experiments for the…

General Relativity and Quantum Cosmology · Physics 2021-04-08 V. G. Gurzadyan , A. Stepanian

We use Vaschy-Buckhingham Theorem as a systematic tool to build univocal n-dimensional extensions of the electric and gravitational fine structure constants and show that their ratio is dimensionally invariant. The results allow us to…

General Physics · Physics 2009-09-29 Fabricio Casarejos , Jaime F. Villas da Rocha , Roberto Moreira Xavier

We study the corrections to the fine-structure constant from the generalized uncertainty principle in the spacetime of a domain wall. We also calculate the corrections to the standard formula to the energy of the electron in the hydrogen…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-20 Luigi Tedesco

In this lecture, I explain the gauge-invariant formulation for perturbations of background spacetimes with untwisted homologous Einstein fibres, which include lots of practically important spacetimes such as static black holes, static black…

High Energy Physics - Theory · Physics 2009-01-28 Hideo Kodama

We derive formulae for the time variation of the gravitational ``constant'' and of the fine structure ``constant'' in various models with extra dimensions and analyze their consistency with the observational data.

General Relativity and Quantum Cosmology · Physics 2007-05-23 E. Garcia-Berro , Yu. A. Kubyshin , P. Loren-Aguilar

We review the observational information on the constancy of the fine structure constant alpha. We find that small improvements on the measurement of ^{187}Re lifetime can provide significant progress in exploring the range of variability…

Astrophysics · Physics 2009-11-07 G. Fiorentini , B. Ricci

We present a theoretical calculation on the time-variability of the fine-structure constant to fit the result of the recent precise analysis of the measurement of the QSO absorption lines. We find the parameters and initial values of the…

Astrophysics · Physics 2008-11-26 Yasunori Fujii

In extensions of general relativity and in theories aiming at unifying gravity with the forces of the Standard Model, the value of the "fundamental constants" is often determined by the vacuum expectation value of new fields, which may thus…

General Relativity and Quantum Cosmology · Physics 2014-03-19 Cosimo Bambi

One of the topical problems of contemporary physics is a possible variability of the fundamental constants. Here we consider possible variability of two dimensionless constants which are most important for calculation of atomic and…

Atomic Physics · Physics 2016-09-08 D. A. Varshalovich , A. Y. Potekhin , A. V. Ivanchik

The observed value of the cosmological constant poses large theoretical problems. We find that topology of the Universe provides a natural source for it. Restricting dynamically an Einstein-Cartan gravity to General Relativity in our…

General Relativity and Quantum Cosmology · Physics 2020-06-16 M. Le Delliou , J. Lorca Espiro

The gravitational force harbours a fundamental instability against collapse. In standard General Relativity without Quantum Mechanics, this implies the existence of black holes as natural, stable solutions of Einstein's equations. If one…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Gerard 't Hooft

In a previous work [1], it was speculated that the lack of homogeneity of the large-scale structure of the universe may be due to quantum fluctuations of space in the early universe. In [1], this was argued for a Friedmann-type universe for…

General Physics · Physics 2019-10-28 Benito Hernández-Bermejo

Evidence that the fine structure constant, alpha, was different in an early epoch has recently been found in quasar (QSO) absorption spectra. An accurate laboratory measurement of alpha variation could help to distinguish between space and…

Atomic Physics · Physics 2016-09-08 E. J. Angstmann , V. A. Dzuba , V. V. Flambaum

There are indications from the study of quasar absorption spectra that the fine structure constant $\alpha$ may have been measurably smaller for redshifts $z>2.$ Analyses of other data ($^{149}$Sm fission rate for the Oklo natural reactor,…

High Energy Physics - Phenomenology · Physics 2009-11-10 Luis Anchordoqui , Haim Goldberg

Speculation that the fine-structure constant $\alpha$ varies in spacetime has a long history. We derive, in 4-D general relativity and in isotropic coordinates, the solution for a charged spherical black hole according to the framework for…

General Relativity and Quantum Cosmology · Physics 2013-11-06 Jacob D. Bekenstein , Marcelo Schiffer

A method offering an order of magnitude sensitivity gain is described for using quasar spectra to investigate possible time or space variation in the fine structure constant, alpha. Applying the technique to a sample of 30 absorption…