We review and elaborate upon a thought experiment of Aharonov and Carmi concerning the inertial and electromagnetic vector potentials. We discuss several conclusions suggested by this experiment which involve extensions of the equivalence principle, and then emphasize the use of the experiment as a predictive tool.

This is the first in a series of papers in which a method of harmonic analysis in terms of functions over the groupSU(2) is applied to the description of interaction between matter and the electromagnetic field. Carmeli'sSU(2) formulation of Maxwell's equations is extended to anSU(2) formulation of the equations for the electromagnetic vector potential. The four functions which describe the vector potential are expanded in a generalized Fourier series [SU(2) harmonic analysis] and the equations for the coefficients are derived. These (...) equations are not independent of each other, but in a given order they can be solved consecutively one at a time. (shrink)