Uniqueness of Scalar Field Energy and Gravitational Energy in the Radiating Regime

Piotr T. Chruściel, Jacek Jezierski, Malcolm A. H. MacCallum
1998 Physical Review Letters  
The usual approaches to the definition of energy give an ambiguous result for the energy of fields in the radiating regime. We show that for a massless scalar field in Minkowski space-time the definition may be rendered unambiguous by adding the requirement that the energy cannot increase in retarded time. We present a similar theorem for the gravitational field, proved elsewhere, which establishes that the Trautman-Bondi energy is the unique (up to a multiplicative factor) functional, within a
more » ... unctional, within a natural class, which is monotonic in time for all solutions of the vacuum Einstein equations admitting a smooth "piece" of conformal null infinity Scri.
doi:10.1103/physrevlett.80.5052 fatcat:5ffyvd6kdnbe7jofe3cs5ryxl4