Flat Space Holography as a limit of AdS/CFT
We construct flat-space holography as a limit of usual AdS/CFT concentrating on the 3d bulk/2d boundary example. The asymptotic group of symmetries at null infinity of flat spacetimes is the infinite dimensional Bondi-Metzner-Sachs (BMS) group. We show how this emerges in the flat-space limit of AdS symmetries. The flat limit also induces a contraction on the CFT which in 2d reduces to the Galilean Conformal Algebra (GCA), studied previously in the context of non-relativistic systems. Quantum gravity in flat space would be described by the representations of the GCA. We comment on the relevant representations of the GCA and correlation functions. We also mention some intriguing results in ongoing work on the "flat" BTZ.