Inhomogeneous High Frequency Expansion-Free Gravitational Waves
arXiv:0706.2556 · doi:10.1103/PhysRevD.75.124012
Abstract
We describe a natural inhomogeneous generalization of high frequency plane gravitational waves. The waves are high frequency waves of the Kundt type whose null propagation direction in space-time has vanishing expansion, twist and shear but is not covariantly constant. The introduction of a cosmological constant is discussed in some detail and a comparison is made with high frequency gravity waves having wave fronts homeomorphic to 2-spheres.
18 pages, Latex file, accepted for publication in Physical Review D