Master Thesis: Properties of mass distributions for discrete cosmology
by
Helena Engström(Stockholm University, Department of Physics)
→
Europe/Stockholm
A5:1041
A5:1041
Description
This thesis addresses the question of how well the FLRW solution of Einstein’s equations is able to describe the locally inhomogeneous observable universe. The effect of local inhomogeneities on the large scale geometry is called backreaktion and to study this effect we will construct discrete models of the universe containing a small number of black holes and solve the constraint equations without any approximations or averaging. To be able to solve the constraint equations exactly our models will consist of topological 3-spheres and we will find a momentarily static solution for which the equations are greatly simplified.
For the mass configurations considered here we will present the metric intrinsic to the hypersurface and construct and illustrate a cell structure dividing the 3-sphere in different regions and use this structure to discuss symmetries of the spacetimes. We will also present values for the Ricci tensor intrinsic to the hypersurface for points at high symmetry.
In the end we will compare the scale factors of the discrete models with the scale factors of the corresponding continuous FLRW models where we define the scale factors from a calculated value of the volume of the corresponding model.
