Nonsymmetric gravitation theories and local Lorentz invariance

We analyze the motion and internal structure of test bodies in theories of gravity which couple the antisymmetric part of a nonsymmetric-tensor gravitational field to the electromagnetic field. We establish that such theories necessarily violate the Einstein equivalence principle by breaking local Lorentz invariance. We also show how atomic-physics experiments designed to test the isotropy of space can be used to test these nonsymmetric theories of gravity. We comment briefly on the constraint such experiments are capable of imposing on Moffat's nonsymmetric gravitation theory, the prototype for the theories of gravity we study.