Abstract: The holographic principle provides a very powerful relation between quantum field theories and theories of quantum gravity. While its most famous avatar, the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, has been extensively studied during the past 25 years, extensions of holography to quantum gravity in de-Sitter or flat space are still under active development. In this talk, I will introduce the main ideas and concepts used to establish holography for asymptotically flat spacetimes in three spacetime dimensions.
A particular focus will be on the basic concepts of the dual Bondi-Metzner-van der Burg-Sachs invariant quantum field theories (possibly with additional u(1) charges) and how to set up a holographic dictionary involving these quantum field theories and asymptotically flat spacetimes.