Inspired by another https://www.physicsforums.com/showthread.php?t=176823", where the discussion drifts toward the (Schroedinger) wave function of photons, I rather like to focus on the electromagnetic (EM) field and its relation to photon(s): What actually is the relation between an EM field and one or more photons. Which, if any, of the following statements comes anywhere near a true statement? A photon is best described by an EM field. Entangled photons share the same EM field. An EM field gives rise to a photon when it interacts with, say, an electron. In the latter case the EM field ceases to exist. No, it depends: if all its energy is used up, it disappears, but if there is energy left, it continues to exist, and this is where the rest of it represents a photon that what previously entangled with the photon swallowed by the electron. Thanks, Harald.