Speaker
Description
I begin with a pedagogical introduction to cosmological particle production during and after inflation, reviewing the theoretical framework of inflaton dynamics, gravitational particle production, and numerical techniques. I discuss various production scenarios studied in different cosmological contexts, with emphasis on computational methods and challenges. I then present our recent work on massive vector dark matter with non-minimal couplings to gravity. Recent studies revealed "runaway" instability in such theories within the effective field theory (EFT) framework. We show this is an artifact of pushing the EFT beyond its validity regime. We construct explicit UV-complete models where non-minimal couplings arise from heavy scalars or Kaluza-Klein gravitons. These completions yield form-factors that automatically satisfy stringent constraints and eliminate all instabilities. We numerically reproduce the dark photon production and delineate the validity boundary, showing that the runaway instability appears only outside the EFT's regime of validity.