- #1
kof9595995
- 679
- 2
Say, I want to couple the angular momenta of a electron spin angular momentum, and a photon's momentum. I guess in terms of representations it's:
[itex]SU(2) \otimes [U(1) \oplus U(1)] = [SU(2) \otimes U(1)] \oplus [SU(2) \otimes U(1)][/itex]
But I'm not at all certain if this is correct, one thing for example, U(1) represents liittle group SO(2), but SU(2) represents SO(3), I probably shouldn't just put them together by a direct product, etc.
[itex]SU(2) \otimes [U(1) \oplus U(1)] = [SU(2) \otimes U(1)] \oplus [SU(2) \otimes U(1)][/itex]
But I'm not at all certain if this is correct, one thing for example, U(1) represents liittle group SO(2), but SU(2) represents SO(3), I probably shouldn't just put them together by a direct product, etc.