TrickyDicky said:Sorry if it is a silly question: Photons have spin-1 and therefore they have theoretically three possible spin states (1,0,-1), For the ±1 case I can see the relation to the ±helicity, but what corresponds physically to the 0 state case?
stevendaryl said:The spin-0 case can be eliminated through a choice of gauge. So it's not considered physical.
stevendaryl said:This issue is discussed here:
http://isites.harvard.edu/fs/docs/icb.topic473482.files/08-gaugeinvariance.pdf (in Section 3.3)
Photon spin is a property of a photon, which is a quantum of light. It describes the intrinsic angular momentum of a photon and can take on three possible states: +1, 0, or -1.
Polarization is the direction of oscillation of the electromagnetic wave that makes up a photon. The polarization of a photon is directly related to its spin, with +1 spin corresponding to vertical polarization, -1 spin corresponding to horizontal polarization, and 0 spin corresponding to circular or elliptical polarization.
Understanding photon spin has many applications in various fields such as quantum computing, telecommunications, and medical imaging. For example, the spin of a photon can be used to encode information in quantum computing and to improve the resolution of medical imaging techniques.
Photon spin can be measured using several methods, including the Stern-Gerlach experiment, which involves passing a beam of photons through a magnetic field and observing the deflection of the beam. Other techniques include using polarizers and interferometers.
No, a photon can only have one of the three possible spin states (+1, 0, or -1). This is a fundamental property of photons and is a result of the quantization of angular momentum in quantum mechanics.