Charge conservation in metric–torsion gravitational theories

Abstract

The concepts of charge conservation and dimensional consistency are employed to derive conditions which uniquely characterize the field equations of electromagnetism and gravitation in a vector–metric–torsion field theory which contains no cosmological constant. Using these results, it is shown that the Einstein–Maxwell field equations are unique among all possible field equations of gravitation and electromagnetism involving a vector field in a metric gravitational theory.