Speaker
Roberto Sussman
(Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (ICN-UNAM), Mexico D.F., Mexico)
Description
Averaging the fully tensorial Einstein equations and their solutions (spacetimes) is an open problem in General Relativity. I present and discuss the proper 3-volume scalar averaging formalism endowed with a non-trivial weight factor, and its application to inhomogeneous cosmologies (LTB and Szekeres models). This formalism leads to a fully determined system of evolution equations for the averaged covariant scalars and their fluctuations and perturbations, allowing for a deeper coordinate independent theoretical understanding of the deviation from FLRW homogeneity, either in terms of a rigorous formalism of exact perturbations over an FLRW abstract background, or through a definition of gravitational entropy in a phase space made by weighed averages of the density and Hubble scalar velocity. I discuss how this weighed scalar averaging can be applied to more general geometries and to various theoretically relevant issues in GR.
Primary author
Roberto Sussman
(Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (ICN-UNAM), Mexico D.F., Mexico)
