The Coupling effects of f(R,Tϕ) gravity on axial gravitational waves

Abstract

The motive of this paper is to study the axial type gravitational waves within flat FRW universe and in the context of f ( R , T ϕ ) gravity (where T ϕ corresponds to the trace of stress energy tensor of ϕ , a scalar field). For this purpose, we consider the famous Regge–Wheeler axial perturbation scheme for geometry as well as assume the corresponding perturbations in the scalar field. We derived the field equations for both unperturbed and axially perturbed scenarios. The simultaneous solution of both sets of field equations lead to some expressions for unknown perturbation parameters. In view of these expressions, we concluded that the propagation of axial gravitational waves is influenced by the scalar field potential and the coupling of geometry and scalar field. The plots of conformal time function emanating from axial metric perturbations, for different values of λ and β , indicate this impact. • Our work is in Modified gravity. • Many researchers which are working in GR not appreciated the Modified gravity.