Evolution of the fine-structure constant in the non-linear regime

Abstract

We study the evolution of the fine-structure constant, α, induced by non-linear density perturbations in the context of the simplest class of quintessence models with a non-minimal coupling to the electromagnetic field, in which the two available free functions (potential and gauge kinetic function) are Taylor-expanded up to linear order. We show that the results obtained using the spherical infall model for an infinite wavelength inhomogeneity are inconsistent with the results of a local linearized gravity study and we argue in favour of the second approach. We also discuss recent claims that the value of α inside virialised regions could be significantly different from the background one on the basis of these findings.

Local experiments see cosmologically varying constants

“…As the local inhomogeneous energy density of the asymptotically FRW spacetime tends to zero, the local spacetime metric exterior to r = R s must tend to the Schwarzschild metric. Similar scenarios have been considered by Wetterich in [10] and in a very recent work by Avelino et al [11]. Whilst our conclusions will be similar to the ones claimed in both of these studies, we believe that neither study proves what is claimed.…”

Impact of the matter density uncertainty on the dark energy reconstruction

“…Hence, throughout this paper we shall assume that the dynamics of φ is fully driven by the scalar field potential, V (φ) (and damped by the expansion). Throughout this paper we shall also neglect the spatial variations of φ which was shown to be a good approximation in this context [40,51,52].…”

“…If the dark energy is described by a quintessence field, φ, non-minimally coupled to the electromagnetic field [29,30,31,32,33,34,35,36,37,38,39,40,41] then the dynamics of α is coupled to the evolution of φ. It was shown [42] that, under certain assumptions, varying couplings may be used to probe the nature of dark energy over a larger redshift range than that spanned by standard methods (such as supernovae [1,2,3,4] or weak lensing [43,44,45]).…”

Cosmological evolution ofαandμand the dynamics of dark energy

“…However, even more spectacular bounds (up to 10 −23 yr −1 [24]) may be available * Electronic address: ppavelin@fc.up.pt in the not too distant future. On a more theoretical front, it was realized that in models where the quintessence field is non-minimally coupled to the electromagnetic field [25,26,27,28,29,30,31,32,33,34,35,36,37] the dynamics of α is directly related to the evolution of the scalar field responsible for the dark energy. It was shown [38], that for a broad class of models, varying couplings may be used to probe the nature of dark energy over a larger redshift range than that spanned by standard methods (such as supernovae [39,40,41,42] or weak lensing [43]).…”

“…Throughout this paper we shall neglect the spatial variations of α and µ which is usually a good approximation [37,44]. These may be relevant in the context of chameleon-type models [45,46] where masses and coupling constants are strongly dependent on the local mass density or if there are domain walls separating regions with different values of the couplings [47].…”