Speaker
Pietro Guarato
(Université de Genève)
Description
In this talk, a detailed analysis of the evolution of tensor perturbations in a cosmological background for a model of Hassan-Rosen theory of bigravity is presented. It is shown that gravitational waves are unstable in this setting, but also that in practice the amplitude of tensor perturbations generated during inflation is sufficiently suppressed to avoid this instability from showing up until today. Hence, this bigravity model cannot be excluded from a pure analysis of the tensor sector. However, stringent limits on inflation from vector and scalar perturbations are derived.
Author
Pietro Guarato
(Université de Genève)
Co-authors
Giulia Cusin
(University of Geneva)
Mariele Motta
(University of Geneva)
Ruth Durrer
(University of Geneva)
