Abstract:
It is shown that in quantum electrodynamics with an external field the intensity
of spontaneous radiation of a charge (in the first order in the radiation field) can be
presented in a form of a functional of classical trajectory. The proof is given for the
case of spinless particles moving in periodic structures, using quasiclassical solutions
of the Klein–Gordon equation. As an example, the explicit calculation is performed
for a flat magnetic ondulator including the first order correction.