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arXiv · 1203.2796

A non-linear approximation for perturbations in ΛCDM

Gerasimos Rigopoulos·Wessel Valkenburg
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Abstract

We describe inhomogeneities in a ΛCDM universe with a gradient series expansion and show that it describes the gravitational evolution far into the non-linear regime and beyond the capacity of standard perturbation theory at any order. We compare the gradient expansion with exact inhomogeneous ΛLTB solutions (Lemaître-Tolman-Bondi metric with the inclusion of a cosmological constant) describing growing structure in a ΛCDM universe and find that the expansion approximates the exact solution well, following the collapse of an over-density all the way into a singularity.

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Gerasimos Rigopoulos, Wessel Valkenburg. 2012-10-18. A non-linear approximation for perturbations in ΛCDM. https://doi.org/10.1103/physrevd.86.043523

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