I’ve seen references on here to photons being “excitations of the EM field”. I have a few questions about those “excitations”. I assume they are eigen-solutions of the 1D wave equation? What are the boundary conditions on the solutions? Is a single photon a single eigen-mode, or a supper-position of more than one mode? Are the solutions normal or complex modes? The reason for some of the questions is that I don’t see how a SINGLE NORMAL mode can transmit information, energy, momentum, or whatever from one place to another. Recommended references appreciated.