Gravitational Causality

par Giulia Isabella (IJCLab)

jeudi 28 avr. 2022, 16:00 → 17:00 Europe/Paris

Bât.210 - Amphi 1 (IJCLab)

I will introduce the Eikonal approximation in gravity from the partial waves expansion of particles with arbitrary spins and masses, which allows us to extract observables such as the time delay or the deflection angle from scattering amplitudes.  I will discuss a notion of causality in gravity usually referred to as "asymptotic causality”, which forbids resolvable time advance and consequent closed time-like loops. I will discuss how asymptotic causality can be satisfied at loop level, by presenting the case of the "photon self-stress", where quantum corrections to the time delay of a photon are obtained by considering 1-loop corrections to its coupling to gravity. I will conclude by considering alternative causality definitions.