Backreaction and the Covariant Formalism of General Relativity
English
Magni, Stefano[University of Luxembourg > Luxembourg Centre for Systems Biomedicine (LCSB) > >]
1-Feb-2012
University of Pavia, Pavia, Italy
Master Degree in Theoretical Physics
Carfora, Mauro
Rasanen, Syksy
[en] General Relativity and Quantum Cosmology ; Astrophysics - Cosmology and Extragalactic Astrophysics
[en] This thesis is a review of backreaction, which is a possible alternative to dark energy and modified gravity. We describe in detail the 3+1 covariant formalism and Frobenius' theorem. We present the averaging procedure developed by Buchert, the Buchert equations and the generalization of these equations to the case of general matter. We then generalize to arbitrary number of spatial dimensions. We focus on the case of 2+1 dimensions, where the relation between the topology and the geometry of a surface imposes a global constraint on backreaction.