skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Cosmological perturbations and structure formation in nonlocal infrared modifications of general relativity

Abstract

We study the cosmological consequences of a recently proposed nonlocal modification of general relativity, obtained by adding a term m{sup 2}R □{sup −2}R to the Einstein-Hilbert action. The model has the same number of parameters as ΛCDM, with m replacing Ω{sub Λ}. At the background level, after fixing m so to reproduce the observed value of Ω{sub M}, we get a pure prediction for the equation of state of dark energy as a function of redshift, w{sub DE}(z), with w{sub DE}(0) in the range [−1.165,−1.135] as Ω{sub M} varies over the broad range Ω{sub M} element of [0.20,0.36]. We find that the cosmological perturbations are well-behaved, and the model fully fixes the dark energy perturbations as a function of redshift z and wavenumber k. The nonlocal model provides a good fit to supernova data and predicts deviations from General Relativity in structure formation and in weak lensing at the level of 3-4%, therefore consistent with existing data but readily detectable by future surveys. For the logarithmic growth factor we obtain γ ≅ 0.53, to be compared with γ ≅ 0.55 in ΛCDM. For the Newtonian potential on subhorizon scales our results are well fitted by Ψ(a;k) = [1+μ{sub s}a{sup s}]Ψ{sub GR}(a;k)more » with a scale-independent μ{sub s} ≅ 0.09 and s ≅ 2, while the anisotropic stress is negligibly small.« less

Authors:
; ; ;  [1];  [2]
  1. Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland)
  2. School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
Publication Date:
OSTI Identifier:
22373515
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2014; Journal Issue: 06; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; EQUATIONS OF STATE; FORECASTING; GENERAL RELATIVITY THEORY; NONLUMINOUS MATTER; PERTURBATION THEORY; POTENTIALS; RED SHIFT

Citation Formats

Dirian, Yves, Foffa, Stefano, Kunz, Martin, Maggiore, Michele, and Khosravi, Nima. Cosmological perturbations and structure formation in nonlocal infrared modifications of general relativity. United States: N. p., 2014. Web. doi:10.1088/1475-7516/2014/06/033.
Dirian, Yves, Foffa, Stefano, Kunz, Martin, Maggiore, Michele, & Khosravi, Nima. Cosmological perturbations and structure formation in nonlocal infrared modifications of general relativity. United States. https://doi.org/10.1088/1475-7516/2014/06/033
Dirian, Yves, Foffa, Stefano, Kunz, Martin, Maggiore, Michele, and Khosravi, Nima. 2014. "Cosmological perturbations and structure formation in nonlocal infrared modifications of general relativity". United States. https://doi.org/10.1088/1475-7516/2014/06/033.
@article{osti_22373515,
title = {Cosmological perturbations and structure formation in nonlocal infrared modifications of general relativity},
author = {Dirian, Yves and Foffa, Stefano and Kunz, Martin and Maggiore, Michele and Khosravi, Nima},
abstractNote = {We study the cosmological consequences of a recently proposed nonlocal modification of general relativity, obtained by adding a term m{sup 2}R □{sup −2}R to the Einstein-Hilbert action. The model has the same number of parameters as ΛCDM, with m replacing Ω{sub Λ}. At the background level, after fixing m so to reproduce the observed value of Ω{sub M}, we get a pure prediction for the equation of state of dark energy as a function of redshift, w{sub DE}(z), with w{sub DE}(0) in the range [−1.165,−1.135] as Ω{sub M} varies over the broad range Ω{sub M} element of [0.20,0.36]. We find that the cosmological perturbations are well-behaved, and the model fully fixes the dark energy perturbations as a function of redshift z and wavenumber k. The nonlocal model provides a good fit to supernova data and predicts deviations from General Relativity in structure formation and in weak lensing at the level of 3-4%, therefore consistent with existing data but readily detectable by future surveys. For the logarithmic growth factor we obtain γ ≅ 0.53, to be compared with γ ≅ 0.55 in ΛCDM. For the Newtonian potential on subhorizon scales our results are well fitted by Ψ(a;k) = [1+μ{sub s}a{sup s}]Ψ{sub GR}(a;k) with a scale-independent μ{sub s} ≅ 0.09 and s ≅ 2, while the anisotropic stress is negligibly small.},
doi = {10.1088/1475-7516/2014/06/033},
url = {https://www.osti.gov/biblio/22373515}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 06,
volume = 2014,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2014},
month = {Sun Jun 01 00:00:00 EDT 2014}
}