Speaker
Description
There are two threads in the research on symmetries of space-time that originated in the 1960s but have been reinvigorated by the increased interest over the past few years: BMS symmetry (later extended by Barnich and Troessaert) and the kinematical symmetries other than Poincare or (anti-)de Sitter (especially the Carroll and Galilei ones). At their intersection, one may consider the Carrollian and Galilean contraction limits of BMS algebras. It turns out that we can consistently define such contractions for 3D BMS and (partially) 3D $\Lambda$-BMS algebras, while in the case of 4D BMS (in the sense of Barnich and Troessaert) we only obtain quasi-Carrollian/Galilean BMS algebras. This can be compared with the recent studies of contractions of the original BMS algebra, in which their authors came to quite different conclusions. Furthermore, in the context of quantum gravity, quantum-group deformations are being generalized to both BMS and various kinematical algebras and hence it should be worthy to also analyze the interplay between the deformations of BMS algebras and their Carrollian or Galilean contractions.
