3 ms·
Just to be clear, I'm not asking how we know quantum amplitudes are in C; I'm asking why, in the same sense as the question "why do we have 3+1 dimensions".
by cperciva 12y ago
Just to be clear, I'm not asking how we know quantum amplitudes are in C; I'm asking why, in the same sense as the question "why do we have 3+1 dimensions".
- gus_massa 12y agoA little late to reply... I should ask a specialist (In Physics, I only have a 50% major.) IIRC it's possible to use any Lie group, but they usually like simple connected groups. In particular, they prefer SU(2) to SO(3) in spite they have the same Lie algebra. (It's actually not an arbitrary preference, to describe spin 1/2 particles like the electron, proton, ... you need to use SU(2). The group SO(3) is useful only with integer spin particles.)