Minimal Electromagnetic Coupling of Spin-Two Fields

Abstract

The apparent increase in the number of degrees of freedom of a massive spin-two field upon introduction of minimal electromagnetic coupling is considered. It is shown that if one gives up the usual formulation of such a system in favor of one possessing fewer dependent field components such a problem does not occur. It is consequently suggested that minimal coupling may be a useful concept only within the framework of theories which are described with a minimal number of components.