Averaging in Cosmology
摘要
In this paper we discuss the effect of local inhomogeneities on the global expansion of nearly FLRW universes, in a perturbative setting. We derive a generic linearized averaging operation for metric perturbations from basic assumptions, and we explicify the issue of gauge invariance. We derive a gauge invariant expression for the back-reaction of density inhomogeneities on the global expansion of perturbed FLRW spacetimes, in terms of observable quantities, and we calculate the effect quantitatively. Since we do not adopt a comoving gauge, our result incorporates the back-reaction on the metric due to scalar velocity and vorticity perturbations. The results are compared with the results by other authors in this field.
引用
@article{arxiv.gr-qc/9711057,
title = {Averaging in Cosmology},
author = {Jelle Boersma},
journal= {arXiv preprint arXiv:gr-qc/9711057},
year = {2009}
}
备注
24 pages, Latex, accepted for publication in Phys. Rev. D