Title:  Making massive dark particles from gravity during inflation

Abstract:  The phenomenon of cosmological gravitational particle production (CGPP) occurs during and after inflation as light fields “feel” the cosmological expansion and their mode functions evolve non-adiabatically.  CGPP is a compelling and minimal explanation for the origin of dark matter, which might only interact gravitationally, as well as other cosmological relics.  In this presentation, I’ll summarize some recent developments in the study of CGPP including our recent study of CGPP for massive spin-2 particles.  I’ll briefly discuss the embedding of massive spin-2 particles into the framework of bigravity, present our results for the spectrum of gravitationally produced particles, and discuss a related by-product of our analysis: an FRW-generalization of the Higuchi bound (ghost-avoidance of massive gravity on dS backgrounds).