Conveners
Monday Session 2
- Nezihe Uzun (Ústav teoretické fyziky MFF UK)
Pierre Mourier
(Centre de Recherche Astrophysique de Lyon, École Normale Supérieure de Lyon)
17/09/2018, 11:00
Properties and dynamics of an inhomogeneous Universe can be described through regional spatial averaging of scalar observables. In relativistic cosmology, the resulting averaged quantities will depend on the choice of space-like hypersurfaces defining the spatial slices of averaging. I will present a general averaging framework that applies to any choice for such a foliation, and the resulting...
Asta Heinesen
(University of Canterbury)
17/09/2018, 11:30
We investigate extremal-foliations and foliation-(in)dependence of averaged space-time quantities, appearing in Buchert's scheme and generalisations hereof. For this purpose we introduce a generalised window-function for spatial hyper surface averaging, and investigate variation of the associated hypersurface-scalar. Surprisingly we find that there are foliation-independent statements to be...
Quentin Vigneron
(CRAL, ENSL, Université Lyon 1)
17/09/2018, 12:00
In Inhomogeneous Cosmology, restricting attention to an irrotational dust matter model, backreaction arises in terms of the deviation of the averaged spatial scalar curvature from a constant-curvature model, $\mathcal{W_D}$, and the kinematical backreaction, $\mathcal{Q_D}$. The resulting cosmological equations can be written in Friedmannian form featuring an effective scalar field in place of...
