Symmetries of Asymptotically Flat Four-Dimensional Spacetimes at Null Infinity Revisited
Symmetries of Asymptotically Flat Four-Dimensional Spacetimes at Null Infinity Revisited
It is argued that the symmetry algebra of asymptotically flat spacetimes at null infinity in 4 dimensions should be taken as the semi-direct sum of supertranslations with infinitesimal local conformal transformations and not, as usually done, with the Lorentz algebra. As a consequence, two dimensional conformal field theory techniques will …