The discussion revolves around the physical interpretation of the spin-0 state in relation to photons, which are understood to have spin-1. Participants explore the implications of this spin classification and its connection to helicity, as well as the role of gauge choice in determining physical states.
Participants express differing views on the physical relevance of the spin-0 state, with some asserting it is non-physical while others seek clarification on its implications. The discussion remains unresolved regarding the interpretation of the spin-0 state.
Participants reference gauge choice as a factor in the discussion, indicating that assumptions about gauge invariance may influence the understanding of spin states. The distinction between massive and massless particles is also noted but not fully explored.
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)