Effect of inhomogeneities on the expansion rate of the universe

By E. Kolb, S. Matarrese, A. Notari, A. Riotto. Physical Review D, 2004

172 citations recorded by the source corpus.

While the expansion rate of a homogeneous isotropic universe is simply proportional to the square-root of the energy density, the expansion rate of an inhomogeneous universe also depends on the nature of the density inhomogeneities. In this paper we calculate to second order in perturbation variables the expansion rate of an inhomogeneous universe and demonstrate corrections to the evolution of the expansion rate. While we find that the mean correction is small, the variance of the correction on the scale of the Hubble radius is sensitive to the physical significance of the unknown spectrum of density perturbations beyond the Hubble radius.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/89e97d92077f8d76d39b7c8dd23e68f9479c85f0

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Citations in the corpus

The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity (2012, background): “If we assume that GR holds, but take inhomogeneities into account, it can be shown that backreaction can cause a global cosmic acceler- ation, without any additional dark energy component (see e.g. Schwarz 2002; Kolb et al. 2005; Räsänen 2006; Wiltshire 2007a; Buchert 2008; Räsänen 2011).”
Backreaction in Late-Time Cosmology (2011, background): “At second order, the effect on the average expansion rate is small [85].”
On the Growth of Perturbations as a Test of Dark Energy and Gravity (2006, background): “General relativity is correct but our understanding of it is not; e.g., long-wavelength density perturbations modify the Friedmann equation (Kolb et al. 2005, 2006).”