Environmental Effects on Spontaneous Emission and Lamb Shift, According to Stochastic Electrodynamics

The environmental effects on the rate of radiative transitions, the Lamb shift and mass renormalization, produced by external modifications of the electromagnetic vacuum, are studied from the point of view of stochastic electrodynamics (SED), using the harmonic oscillator as an atomic model. The vacuum can be modified by adding external radiation to alter the energy content of its modes, or by introducing metallic objects that alter the mode distribution. General formulas are derived for the effects of these modifications on the radiative corrections and some specific cases are calculated yielding the same results as the quantum formalism. A fluctuation-dissipation theorem is obtained, which guarantees the independence of the quantum states from environmental changes; only the radiative corrections are affected by the surroundings. Some conceptual differences between this and the usual quantum approaches are discussed. SED is shown to offer a unified and physically clear explanation of the various external effects on the radiative corrections.