Does GRT Really Allow Gravitational Radiation?

Abstract

The general view in General Relativity is that pure gravitational radiation corresponds to a situation in which curvature tensor equals to Weyl tensor. The problem is that gravitational radiation would correspond to vanishing energy momentum tensor and vanishing energy and momentum. This is additional argument against GRT space-time besides the loss of standard conservation laws assignable to Poincare symmetries, which led to TGD. In TGD framework the so called "massless extremals" (MEs) are extremals of practically any general coordinate invariant action such that curvature tensor reduces to Weyl tensor and interpretation as gravitational radiation is possible. Energy momentum tensor is however non-vanishing and light-like as expected and assigns well-defined four-momentum to gravitational radiation which is also classically quantized to massless quanta.