# Expectation value of X and Y component of angular momentum

by xinoki
Tags: angular, component, expectation, momentum
 P: 6 1. The problem statement, all variables and given/known data Show: ==0 2. Relevant equations Jx=1/2(J++J-) Jy=1/2(J+-J-) 3. The attempt at a solution = < jm l 1/2 J+ l jm> + < jm l j- l jm > = < jm l h/2 sqrt [(j-m)(j+m+1)] + h/2sqrt[(j+m)(j+m+1) l jm > i am not sure how to apply the next step
 P: 1,937 Note that |j,m> is NOT an eigenstate of either J+ or J-. In fact, J+|j,m>=k|j,m+1>, etc. Additionally note that $$=\delta_{m,n}$$