A non-linear approximation for perturbations in ΛCDM

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.

No reviews yet.

No comments yet.