Gravitational plane waves in a non-Riemannian description of Brans-Dicke gravity

Abstract

The gravitational field equations of Brans-Dicke theory are given in a 4-dimensional non-Riemannian space-time with torsion in the language of exterior differential forms A class of pp-wave metrics together with the Brans-Dicke scalar field are used to derive the autoparallel equations of motion for non-spinning test masses. These are compared with the geodesic equations of motion and the differences are pointed out. The effects of the gradient of the Brans-Dicke scalar on the geodesic deviation equations in this non-Riemannian setting are also discussed.