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Cosmic microwave background constraints on the strong equivalence principle

V. Boucher·J. -M. Gerard·P. Vandergheynst·Y. Wiaux
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Abstract

We study the effect of a violation of the strong equivalence principle (SEP) on the cosmic microwave background (CMB). Such a violation would modify the weight of baryons in the primordial gravitational potentials and hence their impact in the establishment of the photon-baryon plasma acoustic oscillations before recombination. This cosmological Nordtvedt effect alters the odd peaks height of the CMB temperature anisotropy power spectrum. A gravitational baryonic mass density of the universe may already be inferred at the first peak scale from the analysis of WMAP data. Experimental constraints on a primordial SEP violation are derived from a comparison with the universe's inertial baryonic mass density measured either in a full analysis of the CMB, or in the framework of the standard big bang nucleosynthesis (BBN).

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V. Boucher, J. -M. Gerard, P. Vandergheynst, Y. Wiaux. 2004-10-26. Cosmic microwave background constraints on the strong equivalence principle. https://doi.org/10.1103/physrevd.70.103528

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