The general structure of electromagnetic interactions in the so-called response representation of quantum electrodynamics(QED)is analysed. A formal solution to the general quantum problem of the electromagnetic fieldinteracting with matter is found. Independently, a formal solution to the corresponding problem in classical stochastic electrodynamics(CSED)is constructed. CSED and QED differ only in the replacement of stochastic averages of c-number fields and currents by time-normal averages of the corresponding Heisenbergoperators. All relations of QED connecting quantum field to quantum current lack Planck's constant, and thus coincide with their counterparts in CSED. In Feynman's terms, one encounters complete disentanglement of the potential and current operators in response picture.
- Macroscopic quantum electrodynamics
- Phase-space methods
- Quantum field theory
- Quantum fluctuations
- Quantum-statistical response problem