ABSTRACT
In a world designed specifically to make easy the learning of quantum physics, the simplest example would be states of position of a free particle or of a particle confined in an atom. Photons allow us to develop the essential formal ideas of quantum physics with an absolute minimum of complexity. A satisfactory theory of photons requires quantum electrodynamics, a branch of advanced quantum theory. The simplest photon polarization state to produce and describe is a state of "linear polarization". It is easy enough to determine whether or not the photons in a beam are in a state of linear polarization. For a linearly polarized beam the state can be exactly specified in terms of the orientation of the polarizer transmission axis for maximum transmission. The behavior of photons in a beam is independent of the intensity of the beam; the photons behave—most conveniently—in a manner independent of one another.
