Using QED, what happens, exactly, when light is created?
Let's say an electron loses energy by dropping to a lower orbital, causing quantum of energy to be "emitted." What is that energy quantum? A massless, size-less "particle" called a photon? But what does that actually mean?
I'm looking for an intuitive explanation, not a mathematical one.
My (limited and probably mistaken) understanding is that the emitted quantum of energy and its associated momentum interacts with the EM field, in such a way that the interaction and the momentum are propagated along a certain vector (ala Maxwell, though I don't understand exactly how it happens). It's those interactions that cause oscillations in the $B$ and $E$ fields, which we call light.
Due to its dual nature, light doesn't travel as a particle, and doesn't have a rest mass. Light is energetic oscillations of the EM field while in transit, observable as either waves or massless particles when it interacts with other things.
What I'm trying to understand better is what happens at the instant the energy quanta is released. From the electron's perspective, the emitted light travels at speed $c$. However, at that speed, time comes to a stop, and near-infinite distances can be traversed instantly. Practically, it's as though a micro wormhole opens at the origin point of the light, the excitation passes through it, and can instantly be on the other end of the Universe. Except those excitations traverse the entire distance, presumably with the $B$ and $E$ fields oscillating the entire time.
How is it that the instantaneous stimulation of the EM field in one location can be propagated indefinitely in the stationary frame, and instantly in the photon's frame, with oscillations visible in the stationary frame, but not in the photon's frame (yes, I understand the photon can't really have a frame, since it's massless -- but can't we just use an electron moving arbitrarily close to $c$ to discuss the same effect?).
What is it about the original energy quantum that makes it so much different in the inertial vs. stationary frames? Since time stops for the light, where do the $E$ and $B$ field oscillations come from? It must be something about the character of that original energy quantum, right?
