Holography for Flat Spacetimes - A Carrollian Adventure

I will review the Carrollian approach to holography in
asymptotically flat spacetimes (AFS). The Carroll group arises in the
vanishing speed of light limit of the Poincare group and its conformal
cousin has been put forward as a possible holographic dual to AFS. In a
nutshell, Carrollian holography states D-dimensional AFS is dual to a
(D-1) dim Carroll CFT. I will highlight past successes in lower dimensions
before focusing on recent work in 4d AFS/3d Carroll CFT, where I will
contrast this to the other popular approach, Celestial holography. I will
also discuss how the Carrollian picture emerges as a limit of AdS/CFT
through Witten diagrams.