On the Relationship between Quantum, Random and Semiclassical Electrodynamics

Abstract

We investigate a form of random electrodynamics in which random electromagnetic fields are used in conjunction with a semiclassical treatment of the Dirac equation. We demonstrate that the S-matrix expansion of this theory is identical with the quantum electrodynamic expansion. We show how one can determine for a particular process whether or not a purely semiclassical calculation will suffice. In particular we show that the Lamb shift needs for its explanation both semiclassical interactions and random field fluctuations.