2013/12/31 by Philippe Brax, Carsten van de Bruck, Sébastien Clesse +3 · 2 citations
Physics and Astronomy · #Astrophysics #Big Bang (financial markets) #Big Bang nucleosynthesis #Black Holes and Theoretical Physics #Classical mechanics #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Equivalence principle (geometric) #General relativity #Nucleosynthesis #Physics #Quantum mechanics #Theoretical physics #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.89.123507
published as Phys. Rev. D 89, 123507 (2014) · 22 pages, 7 figures
arxiv created 2014/05/21 · openalex publication_date 2014/06/13 · arxiv updated 2014/06/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the effects of modifications of gravity after big bang nucleosynthesis which would manifest themselves mainly before recombination. We consider their effects on the cosmic microwave background (CMB) radiation and on the formation of large scale structure. The models that we introduce here represent all screened modifications of general relativity which evade the local tests of gravity such as the violation of the strong equivalence principle as constrained by the Lunar Ranging experiment. We use the tomographic description of modified gravity which defines models with screening mechanisms of the chameleon or Damour-Polyakov types and allows one to relate the temporal evolution of the mass and the coupling to matter of a scalar field to its Lagrangian and also to cosmological perturbations. The models with early modifications of gravity all involve a coupling to matter which is stronger in the past leading to effects on perturbations before recombination while minimizing deviations from \mathrm\ensuremathΛCDM structure formation at late times. We find that a new family of early transition models lead to discrepancies in the CMB spectrum which could reach a few percent and appear as both enhancements and reductions of power for different scales.