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Many models of quintessence predict a time variation of the fundamental constants as well as a composition-dependent gravity like long-range force mediated by the cosmon. We present bounds for the cosmon coupling to matter and radiation…

High Energy Physics - Phenomenology · Physics 2009-11-07 C. Wetterich

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

We study the time variation of fundamental constants in the early Universe. Using data from primordial light nuclei abundances, CMB and the 2dFGRS power spectrum, we put constraints on the time variation of the fine structure constant…

The time variation of fundamental mass scales can have profound cosmological implications. We investigate a particular model of crossover quintessence which is compatible with all present cosmological observations. This model can also…

High Energy Physics - Phenomenology · Physics 2017-08-23 C. Wetterich

Recent experimental data indicates that the fine structure constant alpha may be varying on cosmological time scales. We consider the possibility that such a variation could be induced by a second order phase transition which occurs at late…

High Energy Physics - Phenomenology · Physics 2010-04-05 Z. Chacko , C. Grojean , M. Perelstein

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

Determination of the fine structure constant alpha and search for its possible variation are considered. We focus on a role of the fine structure constant in modern physics and discuss precision tests of quantum electrodynamics. Different…

Atomic Physics · Physics 2015-06-26 Savely G. Karshenboim

The possibility of variations of the values of fundamental constants is a phenomenon predicted by a number of scenarios beyond General Relativity. This can happen if ``our'' fundamental constants are not the actual constants of the…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Cosimo Bambi

Cosmological variation of the fine structure constant $\alpha$ due to the evolution of a spatially homogeneous ultra-light scalar field ($m \sim H_0$) during the matter and $\Lambda$ dominated eras is analyzed. Agreement of $\Delta…

Astrophysics · Physics 2009-11-07 Carl L. Gardner

We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from…

High Energy Physics - Phenomenology · Physics 2010-04-15 Thomas Dent , Steffen Stern , Christof Wetterich

We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-26 Thomas Dent

We propose to generalize Bekenstein model for the time variation of the fine structure "constant" $\alpha_{em}$ to QCD strong coupling constant $\alpha_S$. We find that, except for a ``fine tuned'' choice of the free parameters, the…

Astrophysics · Physics 2011-07-19 N. Chamoun , S. J. Landau , H. Vucetich

The cosmological implications of introducing a variation to the fine structure `constant', \alpha are examined within the context of Loop Quantum Cosmology. The evolution of \alpha is described using the model introduced by Bekenstein,…

General Relativity and Quantum Cosmology · Physics 2016-04-29 David Sloan

We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-16 Carsten van de Bruck , Jurgen Mifsud , Nelson J. Nunes

We make use of Dirac LNH and results for a time varying fine structure constant in order to derive possible laws of variation for speed of light, the number of nucleons in the Universe, energy density and gravitational constant. By…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Marcelo S. Berman , Luis A. Trevisan

We review some of the history and properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to…

General Relativity and Quantum Cosmology · Physics 2014-11-17 John D. Barrow

We review some string-inspired theoretical models which incorporate a correlated spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo;…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Thibault Damour

Changes in the values of the fundamental constants mu, the proton to electron mass ratio, and alpha, the fine structure constant due to rolling scalar fields have been discussed both in the context of cosmology and in new physics such as…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Rodger I. Thompson

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

We consider the problem of the evolution of the fine structure coefficient alpha under the assumption that the scalar field coupling to the Maxwell term satisfies the condition mt>>1 for coherent dark matter oscillations. In this case we…

Astrophysics · Physics 2009-11-10 M. G. Barnett , R. Dick , K. E. Wunderle