Abstract
We define the energy of a perfectly isolated system at a given retarded time as the suitable null limit of the quasilocal energy . The result coincides with the Bondi-Sachs mass. Our is the lapse-unity shift-zero boundary value of the gravitational Hamiltonian appropriate for the partial system contained within a finite topologically spherical boundary . Moreover, we show that with an arbitrary lapse and zero shift the same null limit of the Hamiltonian defines a physically meaningful element in the space dual to supertranslations. This result is specialized to yield an expression for the full Bondi-Sachs four-momentum in terms of Hamiltonian values.
- Received 25 September 1996
DOI:https://doi.org/10.1103/PhysRevD.55.1977
©1997 American Physical Society