English
Related papers

Related papers: Bound on the variation in the fine structure const…

200 papers

The constraints on the time variation of the fine structure constant at recombination epoch relative to its present value, $\Delta\alpha/\alpha \equiv (\alpha_{\mathrm{rec}} - \alpha_{\mathrm{now}})/\alpha_{\mathrm{now}}$, are obtained from…

Astrophysics · Physics 2014-11-18 Masahiro Nakashima , Ryo Nagata , Jun'ichi Yokoyama

Bekenstein's model of a scalar field, \phi, that affects the electromagnetic permeability (usually identified with ``changing \alpha'') predicts tiny variations of the effective fine structure constant up to very high red-shifts,…

High Energy Physics - Phenomenology · Physics 2009-09-15 Keith A. Olive , Maxim Pospelov

The effects of the variation of the dimensionless strong interaction parameter Xq=mq/Lambda{QCD} (mq is the quark mass, Lambda{QCD} is the QCD scale) are enhanced about 1.5 x 10**5 times in the 7.6 eV "nuclear clock" transition between the…

Nuclear Theory · Physics 2009-08-12 V. V. Flambaum , R. B. Wiringa

Various classes of exotic singularity models have been studied as possible mimic models for the observed recent acceleration of the universe. Here we further study one of these classes and, under the assumption that they are…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-15 Mariusz P. Dabrowski , Tomasz Denkiewicz , C. J. A. P. Martins , P. E. Vielzeuf

We calculate bounds on the variation of the fine structure constant at the time of primordial nucleosynthesis and at the time of neutral hydrogen formation. We use these bounds and other bounds from the late universe to test Bekenstein…

We discuss present and future cosmological constraints on variations of the fine structure constant $\alpha$ induced by an early dark energy component having the simplest allowed (linear) coupling to electromagnetism. We find that current…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-08 Erminia Calabrese , Eloisa Menegoni , C. J. A. P. Martins , Alessandro Melchiorri , Graca Rocha

We examine the variation of the fine structure constant in the context of a two-field quintessence model. We find that, for solutions that lead to a transient late period of accelerated expansion, it is possible to fit the data arising from…

Astrophysics · Physics 2009-11-10 M. C. Bento , O. Bertolami , N. M. C. Santos

We update the constraints on the time variation of the fine structure constant $\alpha$ and the electron mass $m_e$, using the latest CMB data, including the 7-yr release of WMAP. We made statistical analyses of the variation of each one of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Susana. J. Landau , Claudia G. Scóccola

Cosmological dark energy is a natural source of variation of the fine structure constant. Using a model-independent approach we show that once general assumptions about the alpha-varying interactions are made, astronomical probes of its…

Astrophysics · Physics 2015-06-24 David Parkinson , Bruce A. Bassett , John D. Barrow

We discuss how laboratory experiments can be used to place constraints on possible variations of the fine structure constant alpha in the observationally relevant redshift interval z ~= 0 - 5, within a rather general theoretical framework.…

Astrophysics · Physics 2009-10-30 Mario Livio , Massimo Stiavelli

The remarkable detection of a spatial variation in the fine-structure constant, alpha, from quasar absorption systems must be independently confirmed by complementary searches. In this letter, we discuss how terrestrial measurements of…

Atomic Physics · Physics 2012-09-11 J. C. Berengut , V. V. Flambaum

The bound on the time variation of the fine structure constant ($\alpha$) driven by the dynamics of quintessence scalar field which is coupled to electromagnetism is discussed using phenomenological quintessential models constrained by SNIa…

Astrophysics · Physics 2009-11-10 Da-Shin Lee , Wolung Lee , Kin-Wang Ng

We critically assess recent claims suggesting that upper limits on the time variation of the fine-structure constant tightly constrain the coupling of a dark energy scalar field to the electromagnetic sector, and, indirectly, the violation…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 P. P. Avelino

Laboratory and astrophysical tests of ''constant variation'' have so far concentrated on the dimensionless fine-structure constant $\alpha$ and on the electron or quark mass ratios $X_{e,q}=m_{e,q}/\Lambda_{\text{QCD}}$, treating the QCD…

High Energy Physics - Phenomenology · Physics 2025-11-20 V. V. Flambaum , A. J. Mansour

State-resolved laser spectroscopy at the 10$^{-12}$ precision level recently reported in $arXiv$:2406.18719 determined the fractional change in nuclear quadrupole moment between the ground and isomeric state of $^{229}\rm{Th}$, $\Delta…

Rolling tachyon field models are among the candidates suggested as explanations for the recent acceleration of the Universe. In these models the field is expected to interact with gauge fields and lead to variations of the fine-structure…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-28 C. J. A. P. Martins , F. M. O. Moucherek

We elaborate on a model of conformal dark energy (dynamical dark energy measured by the conformal age of the universe) recently proposed in [H. Wei and R.G. Cai, arXiv:0708.0884] where the present-day dark energy density was taken to be…

High Energy Physics - Theory · Physics 2008-11-26 Ishwaree P. Neupane

We forecast the ability of future CMB and galaxy lensing surveys to constrain variations of the fine structure constant. We found that lensing data, as those expected from satellite experiments as Euclid could improve the constraint from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Matteo Martinelli , Eloisa Menegoni , Alessandro Melchiorri

We compute primordial light-element abundances for cases with fine structure constant alpha different from the present value, including many sources of alpha dependence neglected in previous calculations. Specifically, we consider…

Astrophysics · Physics 2008-11-26 Kenneth M. Nollett , Robert E. Lopez

We study the cosmological constraints of the time variation of the electron mass $m_e$ and the fine-structure constant $\alpha$, using data of cosmic microwave background, supernovae light curve and baryon acoustic oscillation (BAO) data…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-15 Yo Toda , Osamu Seto