Electric dipole interaction in quantum optics
L. Mandeļ · Physical Review A · 1979
It is pointed out that the electromagnetic interaction $\ensuremath{-}\stackrel{^}{\ensuremath{\mu}}\ifmmode\cdot\else\textperiodcentered\fi{}\stackrel{^}{E}$ between an atom and a field, in which the atom is modelled as a point dipole of moment $\stackrel{^}{\ensuremath{\mu}}$ interacting with the electric field $\stackrel{^}{E}$, is not strictly consistent with both quantum mechanics and Maxwell's equations. Quantum mechanics allows magnetic point dipoles but not electric point dipoles.