Nonlinear evolution of f(R) cosmologies. II. Power spectrum

Journal Article · Mon Dec 15 04:00:00 EST 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.78.123524· OSTI ID:21251113

Oyaizu, Hiroaki; Hu, Wayne ^[1]; Lima, Marcos ^[1]

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1. Kavli Institute for Cosmological Physics, and Enrico Fermi Institute, University of Chicago, Chicago Illinois 60637 (United States)

We carry out a suite of cosmological simulations of modified action f(R) models where cosmic acceleration arises from an alteration of gravity instead of dark energy. These models introduce an extra scalar degree of freedom which enhances the force of gravity below the inverse mass or Compton scale of the scalar. The simulations exhibit the so-called chameleon mechanism, necessary for satisfying local constraints on gravity, where this scale depends on environment, in particular, the depth of the local gravitational potential. We find that the chameleon mechanism can substantially suppress the enhancement of power spectrum in the nonlinear regime if the background field value is comparable to or smaller than the depth of the gravitational potentials of typical structures. Nonetheless power spectrum enhancements at intermediate scales remain at a measurable level for models even when the expansion history is indistinguishable from a cosmological constant, cold dark matter model. Simple scaling relations that take the linear power spectrum into a nonlinear spectrum fail to capture the modifications of f(R) due to the change in collapsed structures, the chameleon mechanism, and the time evolution of the modifications.

• OSTI ID: 21251113
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 12 Vol. 78; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATION
CAPTURE
COSMOLOGICAL CONSTANT
COSMOLOGICAL MODELS
COSMOLOGY
DEGREES OF FREEDOM
DEPTH
EVOLUTION
EXPANSION
GRAVITATION
MASS
NONLINEAR PROBLEMS
NONLUMINOUS MATTER
POTENTIALS
SCALING
SIMULATION
SPECTRA