# Homework Help: Question regarding eigenvalues of angular momentum operator

1. Jan 5, 2009

### valy112

Hello! First of all let me wish you a happy new year!

This is not a homework problem, but rather a curiosity of mine.
In Schwabl's Quantum Mechanics, one can find the proof of the fact that all eigenvalues of the angular momentum Lz are either integers or half-integers, raging from -l to l(l is just a notation they use). My question is, do all these eigenvalues have algebraic multiplicity 1, and if this is true, why?(I guess the fact, if true, should be proved using some subtle physical condition, since using math doesn't seem to work)

Also, does anyone know of a book where I could find information on unitary representation of SU(2)(or of SU(2) in general) and its application to Quantum Mechanics.

Best regards,
Valentin