Graviton, Boundaries, BMS Symmetry and its Cocycles (within the Beltrami Parametrization Scheme)

by Laurent Baulieu

Friday 10 Feb 2023, 11:30 → 13:30 Europe/Zurich

4/2-037 - TH meeting room (CERN)

Once suitably combined with selfdual properties, the Beltrami field parametrization of d=4 metrics illuminates various physical aspects of d=4 GR. Both graviton physical degrees of freedom are geometrically identified as a well defined subset of the 10 fundamental d=4 Beltrami fields. Their emission and absorption processes at the boundaries of asymptotically flat spacetimes gets a quite transparent formulation as well as the Bondi-Metzer-Sachs symmetry that constraints the celestial sphere distortions when they emit or absorb gravitons with non trivial fluxes to or from the spacetime bulk. Cocycles exists that indicates the possibilities of anomalies for the BMS symmetry.