Licentiate: Cosmological tests of massive bigravity

by Mr Jonas Enander (OKC/CoPS)

Friday 7 Dec 2012, 13:15 → 15:00 Europe/Stockholm

FA31

This licentiate thesis investigates phenomenological consequences of the massive bigravity theory formulated in 2011. The massive bigravity theory is the completion of the work started by Fierz and Pauli in 1939 which addressed the question of massive spin-2 fields. Most notably, it allows for the non-linear and consistent formulation of a mass potential for general relativity. As such, it is naturally extended to include two dynamical rank-2 fields. The phenomenological aspect addressed in this work is the question of how cosmological background expansion histories and growth of structure are modified as compared to the standard ΛCDM model. We show that for certain parameter choices the theory is degenerate with ΛCDM at the background expansion level, but that perturbations will invariably break the degeneracy.