Centro de Astrofísica U.Porto

Fine-structure constant constraints on dark energy

C. J. A. P. Martins, A. M. M. Pinho

Abstract
We use astrophysical and atomic clock tests of the stability of the fine-structure constant α $α$ , together with type Ia supernova and Hubble parameter data, to constrain the simplest class of dynamical dark energy models where the same degree of freedom is assumed to provide both the dark energy and (through a dimensionless coupling ζ $ζ$ to the electromagnetic sector) the α $α$ variation. We show how current data tightly constrain a combination of ζ $ζ$ and the dark energy equation of state w0 $w0$ . At the 95% confidence level and marginalizing over w0 $w0$ we find |ζ|<5×10−6 $|ζ|<5×10−6$ , with the atomic clock tests dominating the constraints. The forthcoming generation of high-resolution ultrastable spectrographs will enable significantly tighter constraints.

Keywords
Observational cosmology, Modified theories of gravity, Determination of fundamental constants, Dark energy

Physical Review D
Volume 91, Page 103501
May 2015

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