If one wants to assess how an electron orbits in a hydrogen atom one uses the Schrodinger equation. Ditto for an electron in a magnetic well. However if one wants to assess how particles interact or decay one uses Feyman diagrams, amplitudehrons, or various formulae from Feynman diagrams. The latter is what we usually talk about in CERN or RHC experimental results.
Question: where does Schrodinger stop and Feynman diagrams start? Do we need both? Can I derive the hydrogen s,p orbital shapes from a Feynman diagram(s)?
An electron orbiting a proton is still an interaction; I guess the salient difference is the electron is fundamental and cannot decay. Here Schrodinger typically applies. But could one go Feynman? Both are dynamic over time ... Both seem to calculate probabilities of interaction, and yet have different purposes.