On the energy–momentum density of gravitational plane waves

Abstract

By embedding Einstein's original formulation of general relativity into a broader context, we show that a dynamic covariant description of gravitational stress–energy emerges naturally from a variational principle. A tensor TG is constructed from a contraction of the Bel tensor with a symmetric covariant second degree tensor field Φ and has a form analogous to the stress–energy tensor of the Maxwell field in an arbitrary spacetime. For plane-fronted gravitational waves helicity-2 polarized (graviton) states can be identified carrying non-zero energy and momentum.