Conformal Wave Equation for Graviton via Dimension Reduction

Symmetry is an important concept in modern physics which can be understood via studying the transformations in a physical system. Among the various types of transformations, conformal transformation and conformal symmetry (also referred to as conformal invariance), are of great importance. In this work, we first review the Kaluza-Klein theory through discussing the conformal invariance of the five-dimensional action. Then, by eliminating the extra dimensions of the consequent wave equations, four-dimensional equations are derived, to describe the graviton.