Informal Pizza Seminar

Averaging Quintessence Cosmologies

Iain Brom

Heidelberg

The so-called cosmological backreaction arises when one directly averages the Einstein equations to recover cosmology. While usually applied to avoid employing dark energy models, any cosmological model should strictly be built from such an averaging procedure rather than an assumed background. We apply the Buchert formalism to Einstein-de Sitter, Lambda CDM and quintessence cosmologies, and as a first approach to the full problem, evaluate numerically the discrepancies arising from linear perturbation theory between the averaged behaviour and the assumed behaviour.