On the Energy-Momentum Density of Gravitational Plane Waves

By embedding Einstein’s original formulation of GR 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 space-time. For plane-fronted gravitational waves helicity-2 polarised (graviton) states can be identified carrying non-zero energy and momentum. MSC codes: 83D05, 83C40, 83C35