English
Related papers

Related papers: Revised fits to $\Delta\alpha/\alpha$ in consisten…

200 papers

We briefly review the recent experimental results on possible variations of the fine structure constant $\alpha$ on the cosmological time scale and its position dependence. We outline the theoretical grounds for the assumption that $\alpha$…

General Relativity and Quantum Cosmology · Physics 2012-05-11 K. A. Bronnikov , S. A. Kononogov

We show that the Supernovae results, implying evidence for an accelerating Universe, may be closely related to the recent discovery of redshift dependence in the fine structure constant $\alpha$. The link is a class of varying speed of…

Astrophysics · Physics 2009-10-31 John D. Barrow , Joao Magueijo

We introduce a model which allows the fine structure constant (alpha) to vary throughout space and time due to a coupling to a scalar field with a non-canonical kinetic structure. This provided a new extension of the…

General Relativity and Quantum Cosmology · Physics 2015-01-20 Alexander A. H. Graham

I review recent constraints on and claimed detections of a time-varying fine-structure constant $\alpha$. Our results are consistent with no variation in $\alpha$ from the epoch of recombination to the present day, and restrict any such…

High Energy Physics - Phenomenology · Physics 2016-09-06 C. J. A. P. Martins

We propose a new method to probe a possible time evolution of the fine structure constant $\alpha$ from X-ray and Sunyaev-Zeldovich measurements of the gas mass fraction ($f_{gas}$) in galaxy clusters. Taking into account a direct relation…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-01 R. F. L. Holanda , S. J. Landau , J. S. Alcaniz , I. E. Sanchez G. , V. C. Busti

Dynamical models of dark energy can imply that the fine structure constant $\alpha$ varies over cosmological time scales. Data on shifts in resonance energies $E_r$ from the Oklo natural fission reactor have been used to place restrictive…

Nuclear Theory · Physics 2015-10-13 Leila Hamdan , Edward D. Davis

We use recent astrophysical and local tests of the stability of the fine-structure constant, $\alpha$, to constrain a particular phenomenological but physically motivated class of models in which the dark energy equation of state can…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-12 C. J. A. P. Martins , M. Prat Colomer

Assuming a Friedmann universe which evolves with a power-law scale factor, $a=t^{n}$, we analyse the phase space of the system of equations that describes a time-varying fine structure 'constant', $\alpha$, in the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John D. Barrow , David F. Mota

Recent astrophysical observations of quasar absorption systems indicate that the fine structure constant $\alpha$ and the proton-electron mass ratio $\mu$ may have evolved through the history of the universe. Motivated by these…

Astrophysics · Physics 2008-11-26 Seokcheon Lee

Most of the successful physical theories rely on the constancy of few fundamental quantities (such as the speed of light, $c$, the fine-structure constant, \alpha, the proton to electron mass ratio, \mu, etc), and constraining the possible…

Astrophysics · Physics 2008-11-26 Raghunathan Srianand , Hum Chand , Patrick Petitjean , Bastien Aracil

We discuss how existing astrophysical measurements of various combinations of the fine-structure constant $\alpha$, the proton-to-electron mass ratio $\mu$ and the proton gyromagnetic ratio g$_{p}$ towards the radio source PKS1413+135 can…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-01 A. M. R. V. L. Monteiro , M. C. Ferreira , M. D. Julião , C. J. A. P. Martins

Absorption-line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine-structure constant, alpha, and the proton-to-electron mass ratio, mu = m_p/m_e, as…

We analyse the constraints obtained from new atomic clock data on the possible time variation of the fine structure `constant' and the electron-proton mass ratio and show how they are strengthened when the seasonal variation of Sun's…

High Energy Physics - Phenomenology · Physics 2008-11-26 John D. Barrow , Douglas J. Shaw

This letter explores how a reinterpretation of the generalized uncertainty principle as an effective variation of Planck's constant provides a physical explanation for a number of fundamental quantities and couplings. In this context, a…

General Physics · Physics 2024-09-02 Ahmed Farag Ali , Jonas Mureika , Elias C. Vagenas , Ibrahim Elmashad

The cosmological evolution of a quintessence-like scalar field, phi, coupled to matter and gauge fields leads to effective modifications of the coupling constants and particle masses over time. We analyze a class of models where the scalar…

Astrophysics · Physics 2009-09-15 Seokcheon Lee , Keith A. Olive , Maxim Pospelov

Recent key observational results on the variation of fine structure constant, the proton to electron mass ratio and the gravitational constant are reviewed. The necessity to substantiate the dark sector of cosmology and to test gravity on…

Astrophysics · Physics 2015-06-24 Jean-Philippe Uzan

Calculation of the Dirac hydrogen atom spectrum in the framework of dynamical fine structure constant (alpha) variability discloses a small departure in the laboratory from Sommerfeld's formula for the fine structure shifts, possibly…

Astrophysics · Physics 2007-05-23 Jacob D. Bekenstein

We study the space-time evolution of the fine structure constant, $\alpha$, inside evolving spherical overdensities in a lambda-CDM Friedmann universe using the spherical infall model. We show that its value inside virialised regions will…

Astrophysics · Physics 2011-05-05 D. F. Mota , J. D. Barrow

Current analyses of VLT/UVES quasar spectra disagree with the Keck/HIRES evidence for a varying fine-structure constant, alpha. To investigate this we introduce a simple method for calculating the minimum possible uncertainty on…

Astrophysics · Physics 2015-06-24 M. T. Murphy , J. K. Webb , V. V. Flambaum

In their Letter [Phys. Rev. Lett. 92, 121302 (2004)] (also [Astron. Astrophys. 417, 853 (2004)]), Srianand et al. analysed optical spectra of heavy-element species in 23 absorption systems along background quasar sight-lines, reporting…

Astrophysics · Physics 2009-06-23 Michael T. Murphy , John K. Webb , Victor V. Flambaum