Modeling Background Radiation in Isotropic Cosmologies

TL;DR

This paper models cosmic background gravitational radiation using perturbations of isotropic cosmologies, deriving an isotropic tensor analogous to the Bel-Robinson tensor to explore energy-momentum properties.

Contribution

It introduces a novel approach to represent isotropic gravitational radiation in cosmological models via explicit perturbations and tensor construction.

Findings

Derived an isotropic tensor similar to the Bel-Robinson tensor

Provided a framework to associate energy-momentum with gravitational radiation

Addressed the analogy with cosmic microwave background radiation

Abstract

Using explicit perturbations of isotropic cosmological models which describe simple gravitational waves, an isotropic tensor having the algebraic symmetries of the Bel-Robinson tensor is derived as a model of cosmic background gravitational radiation and this is used to provide an answer to the question: in what sense can an energy-momentum-stress tensor similar to that describing the cosmic microwave background radiation (neglecting anisotropies) be associated with an isotropic background of gravitational radiation?