High Energy Particle Theory Seminar: Rachel A Rosen - “On Causality Conditions in de Sitter Spacetime”

Causality conditions provide powerful constraints on low energy theories. In this talk, I will discuss how standard causality conditions of AdS and flat spacetimes can be extended to de Sitter. In particular, I will consider the Shapiro time delay experienced by a particle in a black hole or shockwave background and discuss how “fastest null geodesics” can be defined using spatial shifts on the boundary of de Sitter and the relevance of the “stretching” of the de Sitter Penrose diagram. I will discuss the case of a photon with a non-canonical coupling as an illustrative example.
Host: Yuan Xin (yuan.xin@yale.edu)