We first investigate the form the general relativity theory would have taken had the gravitational mass and the inertial mass of material objects been different. We then extend this analysis to electromagnetism and postulate an equivalence principle for the electromagnetic field. We argue that to each particle with a different electric charge-to-mass ratio in a gravitational and electromagnetic...

Abstract We propose a general model where quintessence couples to electromagnetism via its kinetic term. This novelty generalizes the linear dependence of gauge function on ϕ , commonly adopted in literature. The interaction naturally induces time variation fine-structure constant that can be formulated within disformally coupled framework, akin Gordon metric. Through suitable parametrization s...

Standard formulae of classical electromagnetism for the forces between electric charges in motion derived from retarded potentials are compared with those obtained from a recently developed relativistic classical electrodynamic theory with an instantaneous inter-charge force. Problems discussed include small angle Ruther-ford scattering, Jackson's recent 'torque paradox' and circular Keplerian ...