Classical electromagnetism as a consequence of Coulomb's law, special relativity and Hamilton's principle and its relationship to quantum electrodynamics**This paper is dedicated in the memory of Valentine Telegdi.

Abstract

It is demonstrated how all the mechanical equations of classical electromagnetism (CEM) may be derived from only Coulomb's inverse square force law, special relativity and Hamilton's principle. The instantaneous nature of the Coulomb force in the centre-of-mass frame of two interacting charged objects, mediated by the exchange of space-like virtual photons, is predicted by quantum electrodynamics (QED). The interaction Lagrangian of QED is shown to be identical, in the appropriate limit, to the potential energy term in the Lorentz-invariant Lagrangian of CEM. A comparison is made with the Feynman–Wheeler action-at-a-distance formulation of CEM.