I'm getting confused with the idea of probability(Schrodinger) waves and photons. Is the wave side of a photon a probability wave or an electromagnetic wave or both? In the 2 slit experiment with 1 photon at a time, it seems like a photon is described by a probability wave with a probability of going through either slit. However we all know that light is made of electromagnetic radiation. How do these fit together in the case of photons?