Non-linear cosmological collapse of quintessence

TL;DR

This paper investigates the relativistic spherical collapse of quintessence in cosmology using numerical relativity, comparing it to traditional models and exploring the effects of inhomogeneities on local expansion.

Contribution

It introduces a fully relativistic numerical method to study quintessence collapse and compares results with the top-hat model, highlighting the small impact of quintessence inhomogeneities.

Findings

Quintessence inhomogeneities remain small due to momentum transfer.

The method validates the impact of inhomogeneities on local expansion.

Comparison shows differences between relativistic and top-hat models.

Abstract

We present a study of the fully relativistic spherical collapse in presence of quintessence using on Numerical Relativity, following the method proposed by the authors in a previous article [arXiv:1409.3476]. We ascertain the validity of the method by studying the evolution of a spherically symmetric quintessence inhomogeneity on a de Sitter background and we find that it has an impact on the local expansion around the centre of coordinates. We then proceed to compare the results of our method to those of the more largely adopted top-hat model. We find that quintessence inhomogeneities do build up under the effect that matter inhomogeneities have on the local space-time yet remain very small due to the presence of momentum transfer from the over-dense to the background regions. We expect that these might have an even more important role in modified theories of gravitation.