Backreaction of Cosmological Perturbations in Covariant Macroscopic Gravity

Abstract

The problem of corrections to Einstein's equations arising from averaging of inhomogeneities ("backreaction") in the cosmological context, has gained considerable attention recently. We present results of analysing cosmological perturbation theory in the framework of Zalaletdinov's fully covariant Macroscopic Gravity. We show that this framework can be adapted to the setting of cosmological perturbations in a manner which is free from gauge related ambiguities. We derive expressions for the backreaction which can be readily applied in \emph{any} situation (not necessarily restricted to the linear perturbations considered here) where the \emph{metric} can be brought to the perturbed FLRW form. In particular these expressions can be employed in toy models studying nonlinear structure formation, and possibly also in N-body simulations. Additionally, we present results of example calculations which show that the backreaction remains negligible well into the matter dominated era.

17 pages, 5 figures, revtex4; v2 -- typos fixed, 1 reference updated, to appear in Phys Rev D

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Cited by in corpus (11)

• What is dust? - Physical foundations of the averaging problem in cosmology
• Cosmological equivalence principle and the weak-field limit
• Applicability of the linearly perturbed FRW metric and Newtonian cosmology
• Cosmic Inhomogeneities and the Average Cosmological Dynamics
• Position and frequency shifts induced by massive modes of the gravitational wave background in alternative gravity
• Averaging Robertson-Walker Cosmologies
• Effect of inhomogeneities on high precision measurements of cosmological distances
• Expansion and Growth of Structure Observables in a Macroscopic Gravity Averaged Universe
• Nonlinear Structure Formation, Backreaction and Weak Gravitational Fields
• The effect of cosmic inhomogeneities on the average cosmological dynamics
• An Almost-FLRW Universe as the Averaged Geometry in Macroscopic Gravity