Parametrization for the Scale Dependent Growth in Modified Gravity
Abstract
We propose a scale dependent analytic approximation to the exact linear growth of density perturbations in Scalar-Tensor (ST) cosmologies. In particular, we show that on large subhorizon scales, in the Newtonian gauge, the usual scale independent subhorizon growth equation does not describe the growth of perturbations accurately, as a result of scale-dependent relativistic corrections to the Poisson equation. A comparison with exact linear numerical analysis indicates that our approximation is a significant improvement over the standard subhorizon scale independent result on large subhorizon scales. A comparison with the corresponding results in the Synchronous gauge demonstrates the validity and consistency of our analysis.
Cite
@article{arxiv.1004.4905,
title = {Parametrization for the Scale Dependent Growth in Modified Gravity},
author = {Juan C. Bueno Sanchez and James B. Dent and Sourish Dutta and Leandros Perivolaropoulos},
journal= {arXiv preprint arXiv:1004.4905},
year = {2010}
}
Comments
10 pages, 5 figures. Minor modifications and references added to match published version