Abstract
It is shown that the symmetry algebra of asymptotically flat spacetimes at null infinity in 4 dimensions should be taken as the semidirect 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 play as fundamental a role in this context of direct physical interest as they do in three-dimensional anti–de Sitter gravity.
- Received 18 May 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.111103
© 2010 The American Physical Society