Hi Everybody, I'm currently working my way through Sakurai's second book, "Advanced Quantum Mechanics." I'm getting held up on a short several paragraphs on the connection between photon spin and polarization. On pages 42-43, Sakurai states: "Since the polarization transforms like a vector, the general theory of angular momentum encourages us to associate it with one unit of angular momentum. This is what is meant by the statement that they photon has one unit of spin angular momentum. [He then goes on to describe the circular polarization basis, and how individual photons are have spin parallel or antiparallel to the propagation direction.]" So does this mean that all photons taken individually, are always circularly polarized? I want to say that I'm missing something, but this seems to be what he is saying. If someone could clarify this discussion on pages 42-43 of Sakurai's AQM, I'd really appreciate the help.