FLRW-Cosmology in Generic Gravity Theories

Abstract

We prove that for the Friedmann-Lemaitre-Robertson-Walker metric, the field equations of any generic gravity theory in arbitrary dimensions are of the perfect fluid type. The cases of general Lovelock and $\mathcal{F}(R,\mathcal{G})$ theories are given as examples.

9 pages, published version in Eur. Phys. J. C