In this talk I present a study of scalar QED in (3+1)-dimensional de Sitter space. Building on recent technical advances in QFT on Anti–de Sitter space, we propose gauge‑invariant observables in de Sitter and compute them explicitly in perturbation theory, up  to one loop order. Along the way I will explain the analytic continuation to Euclidean AdS and time-permitting review a few interesting AdS phenomena for scalar QED with unusual boundary conditions. Back to dS, I will discuss a Debye‑screening–like effect in a cosmological setting.

Link to Zoom registration
https://zoom.us/meeting/register/A02wEI6WSdO9SBbA5FdJ7w