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Cosmological effects of scalar-photon couplings: dark energy and varying-? models

Avgoustidis, Anastasios; Martins, C.J.A.P.; Monteiro, A.M.R.V.L.; Vielzeuf, P.E.; Luzzi, G.


C.J.A.P. Martins

A.M.R.V.L. Monteiro

P.E. Vielzeuf

G. Luzzi


We study cosmological models involving scalar fields coupled to radiation and discuss their effect on the redshift evolution of the cosmic microwave background temperature, focusing on links with varying fundamental constants and dynamical dark energy. We quantify how allowing for the coupling of scalar fields to photons, and its important effect on luminosity distances, weakens current and future constraints on cosmological parameters. In particular, for evolving dark energy models, joint constraints on the dark energy equation of state combining BAO radial distance and SN luminosity distance determinations, will be strongly dominated by BAO. Thus, to fully exploit future SN data one must also independently constrain photon number non-conservation arising from the possible coupling of SN photons to the dark energy scalar field. We discuss how observational determinations of the background temper- ature at different redshifts can, in combination with distance measures data, set tight constraints on interactions between scalar fields and photons, thus breaking this degeneracy. We also discuss prospects for future improvements, particularly in the context of Euclid and the E-ELT and show that Euclid can, even on its own, provide useful dark energy constraints while allowing for photon number non-conservation.


Avgoustidis, A., Martins, C., Monteiro, A., Vielzeuf, P., & Luzzi, G. (2014). Cosmological effects of scalar-photon couplings: dark energy and varying-? models. Journal of Cosmology and Astroparticle Physics, 2014(6),

Journal Article Type Article
Acceptance Date Jun 9, 2014
Publication Date Jun 27, 2014
Deposit Date Jul 14, 2016
Publicly Available Date Jul 14, 2016
Journal Journal of Cosmology and Astroparticle Physics
Electronic ISSN 1475-7516
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 2014
Issue 6
Public URL
Publisher URL


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