Coupled two-quantum-transition probability for laser photons and microwave plasmons.
The introduction of a plasmon-state vector analogous to a photon-field oscillator allows, within the rotating-wave approximation, transformation to a time-independent interaction Hamiltonian, so that Fermi's golden rule can be applied to the two-quantum transition. Although the existence of a vector potential is necessary for the oscillator state vectors, only the multipolar Hamiltonian need be used for the off-resonant frequencies.
Hildebrandt
J
J