Nonlocality of the Effective Interaction of the Radiation Field with a Strong External Electromagnetic Field

摘要

We investigate the problem of nonlocality of the effective interaction of the radiation field with a strong externalfield. It is shown that the use of a Lagrangian or Hamiltonian interaction density with a nonlocal form-factor forparametrizing this interaction is inconsistent. An interaction operator that allows one to take into account thenatural the natural nolocality of this interaction is derived from the analysis of the relevant Feynman diagramsof quantum electrodynamics.