Dispersion of growth of matter perturbations in f(R) gravity
- Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)
- IUCAA, Post Bag 4, Ganeshkhind, Pune 411 007 (India)
- Laboratoire de Physique Theorique et Astroparticules, CNRS, Universite Montpellier II, Place E. Bataillon, Case 70, 34095 Montpellier Cedex 05 (France)
We study the growth of matter density perturbations {delta}{sub m} for a number of viable f(R) gravity models that satisfy both cosmological and local gravity constraints, where the Lagrangian density f is a function of the Ricci scalar R. If the parameter m{identical_to}Rf{sub ,RR}/f{sub ,R} today is larger than the order of 10{sup -6}, linear perturbations relevant to the matter power spectrum evolve with a growth rate s{identical_to}dln{delta}{sub m}/dlna (a is the scale factor) that is larger than in the {lambda}CDM model. We find the window in the free parameter space of our models for which spatial dispersion of the growth index {gamma}{sub 0}{identical_to}{gamma}(z=0) (z is the redshift) appears in the range of values 0.40 < or approx. {gamma}{sub 0} < or approx. 0.55, as well as the region in parameter space for which there is essentially no dispersion and {gamma}{sub 0} converges to values around 0.40 < or approx. {gamma}{sub 0} < or approx. 0.43. These latter values are much lower than in the {lambda}CDM model. We show that these unusual dispersed or converged spectra are present in most of the viable f(R) models with m(z=0) larger than the order of 10{sup -6}. These properties will be essential in the quest for f(R) modified gravity models using future high-precision observations and they confirm the possibility to distinguish clearly most of these models from the {lambda}CDM model.
- OSTI ID:
- 21325388
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 80, Issue 8; Other Information: DOI: 10.1103/PhysRevD.80.084044; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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