2018/07/31 by C. M. S. Barbosa, Hermano Velten, H. Velten +2
Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Dark energy #Galaxies: Formation, Evolution, Phenomena #General relativity #Geometry #Mathematical physics #Newtonian fluid #Physics #Quantum #Quantum gravity #Quantum mechanics #Scalar (mathematics) #Sigma #Theoretical physics #astro-ph.CO #f(R) gravity #gr-qc
paper · pdf · doi:10.1103/physrevd.98.123522
published as Phys. Rev. D 98, 123522 (2018) · 10 pages, 6 figures. Matches PRD version
openalex publication_date 2018/12/19 · arxiv created 2018/12/26 · arxiv updated 2019/01/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Cosmological scalar perturbation theory studied in the Newtonian gauge depends on two potentials \mathrm\ensuremathΦ and \mathrm\ensuremathΨ. In general relativity (GR), they must coincide (\mathrm\ensuremathΦ=\mathrm\ensuremathΨ) in the absence of anisotropic stresses sourced by the energy-momentum tensor. On the other hand, it is widely accepted in the literature that potential deviations from GR can be parametrized by \mathrm\ensuremathΦ\ensuremath≠\mathrm\ensuremathΨ. The latter feature is therefore present in both GR cosmologies equipped with shear viscous fluids or modified gravity. We study the evolution of scalar matter density perturbations using the redshift-space-distortion-based f(z)\ensuremathσ8(z) data as a tool to differentiate and characterize the imprints of both scenarios. We show that in the f(z)\ensuremathσ8(z) evolution both scenarios yield to completely different imprints in comparison to the standard cosmology. While the current available data are not sensitive to distinguish modified gravity from viscous shear cosmologies, future precise data can be used to break this indistinguishability.