Cosmological Effects of Scalar-Photon Couplings: Dark Energy and Varying-alpha Models

Abstract

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 temperature 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.

29 pages, 11 figures; v2: Matches published version (JCAP)

References in corpus (9)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• Cosmology and fundamental physics with the Euclid satellite
• Baryon Acoustic Oscillations in the Ly-α forest of BOSS quasars
• Measuring D_A and H at z=0.35 from the SDSS DR7 LRGs using baryon acoustic oscillations
• Is there Correlation between Fine Structure and Dark Energy Cosmic Dipoles?
• Time-variability of alpha from realistic models of Oklo reactors
• Probing dark energy with redshift-drift
• Constraining cosmologies with fundamental constants I. Quintessence and K-Essence

Cited by in corpus (18)

• Cosmology and Fundamental Physics with the Euclid Satellite
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• Quintessential Inflation with $\alpha$-attractors
• Euclid: Forecast constraints on the cosmic distance duality relation with complementary external probes
• Breaking of the equivalence principle in the electromagnetic sector and its cosmological signatures
• Constraining the evolution of the CMB temperature with SZ measurements from Planck data
• Machine Learning meets the redshift evolution of the CMB Temperature
• Fundamental cosmology in the E-ELT era: The status and future role of tests of fundamental coupling stability
• Constraining spatial variations of the fine structure constant using clusters of galaxies and Planck data
• Sub-percent constraints on cosmological temperature evolution
• Testing distance duality with CMB anisotropies
• Reappraisal of the limit on the variation in $\alpha$ implied by Oklo
• Fundamental Cosmology from Precision Spectroscopy: I. Varying Couplings
• Further consistency tests of the stability of fundamental couplings
• New Constraints on Spatial Variations of the Fine Structure Constant from Clusters of Galaxies
• Observables in theories with a varying fine structure constant
• Redshifting of cosmological black bodies in BSBM varying-alpha theories
• Fundamental Cosmology from Precision Spectroscopy: II. Synergies with supernovae