Classical Soft Graviton Theorem due to Scalar Fields on 4-D Minkowski Background

The classical soft graviton theorem expresses the behavior of low-frequency gravitational radiation. In this paper, simplistic proofs of the classical soft graviton theorem for massless and massive scalar fields on $4$-D Minkowski background are presented without considering the correction to the behavior of scalar fields and gravitational stress-energy tensor due to the perturbation in the background.