Hello. I am new to this forum, and certainly no expert in quantum physics. I am here to try to learn new things, if possible.
The thing that really struck me after viewing all four of the Feynman lectures was how blatantly it all seems to violate Special Relativity. The Feynman diagrams seem to utterly disregard whether interacting particles are within each other's light cone. Apparently, an electron can be affected by a photon it hasn't met yet, at least in some reference frames, but has met in others. Is this correct?
Maxwell's Equations are relativity-friendly, being preserved under a Lorentz transformation. I would have hoped that the broader theory of QED would be similarly preserved, but maybe I'm wrong.
In the first two lectures, Feynman attributed wavelength as an attribute of the photon, but in the middle of the third lecture he stated this was not really true. There is only one kind of photon, with only the distribution of amplitudes that can vary. This is approximately the point where I got totally lost. Is there a simple explanation of what he meant?
Any comments anyone can offer would be appreciated.