BMS flux-balance equations as constraints on the gravitational radiation


Presenting author: Ali Seraj


Asymptotically flat spacetimes admit and infinite dimensional symmetry algebra known as BMS, which in particular includes Poincare symmetries. We derive their associated flux-balance laws in terms of radiative multipole moments at null infinity to all orders in post-Minkowskian expansion. The ten Poincare balance equations agree with previous results, while completing them in the PM expansion. The BMS balance equations are novel and impose infinite number of constraints on the gravitational waveforms, as also proposed recently by Ashtekar et al. We show that the quadrupolar super-translation and super-Lorentz flux-balance laws give non-trivial constraints at 3PN and 2.5PN order, respectively. Our analysis also confirms the surface charge expression for the angular momentum at null infinity derived previously from the sub- leading soft graviton theorem.

Oral presentation: yes. Poster: no.