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

Title: f(R) gravity and chameleon theories

Abstract

We analyze f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, the existence of a matter dependent mass and a thin-shell effect allows one to alleviate these constraints. The thin-shell condition also implies strong restrictions on the cosmological dynamics of the f(R) theories. As a consequence, we find that the equation of state of dark energy is constrained to be extremely close to -1 in the recent past. We also examine the potential effects of f(R) theories in the context of the Eoet-wash experiments. We show that the requirement of a thin shell for the test bodies is not enough to guarantee a null result on deviations from Newton's law. As long as dark energy accounts for a sizeable fraction of the total energy density of the Universe, the constraints that we deduce also forbid any measurable deviation of the dark energy equation of state from -1. All in all, we find that both cosmological and laboratory testsmore » imply that f(R) models are almost coincident with a {lambda}CDM model at the background level.« less

Authors:
 [1];  [2];  [3];  [4]
  1. Institut de Physique Theorique CEA, IPhT, F-91191 Gif/Yvette, France, CNRS, URA 2306, F-91191, Gif/Yvette (France)
  2. Department of Applied Mathematics, The University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom)
  3. Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, Cambridge CB2 0WA (United Kingdom)
  4. Astronomy Units, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)
Publication Date:
OSTI Identifier:
21250922
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 78; Journal Issue: 10; Other Information: DOI: 10.1103/PhysRevD.78.104021; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; EINSTEIN FIELD EQUATIONS; ENERGY DENSITY; EQUATIONS OF STATE; GRAVITATION; MASS; MODIFICATIONS; NONLUMINOUS MATTER; QUANTUM GRAVITY; SCALAR FIELDS; STRONG-COUPLING MODEL; UNIVERSE

Citation Formats

Brax, Philippe, Bruck, Carsten van de, Davis, Anne-Christine, and Shaw, Douglas J. f(R) gravity and chameleon theories. United States: N. p., 2008. Web. doi:10.1103/PHYSREVD.78.104021.
Brax, Philippe, Bruck, Carsten van de, Davis, Anne-Christine, & Shaw, Douglas J. f(R) gravity and chameleon theories. United States. doi:10.1103/PHYSREVD.78.104021.
Brax, Philippe, Bruck, Carsten van de, Davis, Anne-Christine, and Shaw, Douglas J. Sat . "f(R) gravity and chameleon theories". United States. doi:10.1103/PHYSREVD.78.104021.
@article{osti_21250922,
title = {f(R) gravity and chameleon theories},
author = {Brax, Philippe and Bruck, Carsten van de and Davis, Anne-Christine and Shaw, Douglas J.},
abstractNote = {We analyze f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, the existence of a matter dependent mass and a thin-shell effect allows one to alleviate these constraints. The thin-shell condition also implies strong restrictions on the cosmological dynamics of the f(R) theories. As a consequence, we find that the equation of state of dark energy is constrained to be extremely close to -1 in the recent past. We also examine the potential effects of f(R) theories in the context of the Eoet-wash experiments. We show that the requirement of a thin shell for the test bodies is not enough to guarantee a null result on deviations from Newton's law. As long as dark energy accounts for a sizeable fraction of the total energy density of the Universe, the constraints that we deduce also forbid any measurable deviation of the dark energy equation of state from -1. All in all, we find that both cosmological and laboratory tests imply that f(R) models are almost coincident with a {lambda}CDM model at the background level.},
doi = {10.1103/PHYSREVD.78.104021},
journal = {Physical Review. D, Particles Fields},
number = 10,
volume = 78,
place = {United States},
year = {Sat Nov 15 00:00:00 EST 2008},
month = {Sat Nov 15 00:00:00 EST 2008}
}