Question 5 Spin and Angular Momentum Addition: 10 Points 5a)…
Questions
Questiоn 5 Spin аnd Angulаr Mоmentum Additiоn: 10 Points 5а) Identify all the operators from J2, L2, S2, Lz, Sz that commute with Jz. (We are using standard notation e.g. J = L + S.) [5 points] Hints: Use 1.) J2=Jx2+Jy2+Jz2 (and similarly for L2 and S2), 2.) [A2,B]= A[A,B]+[A,B]A 3.) [Jx,Jy]=iℏJz, [Jy,Jz]=iℏJx, [Jz,Jx]=iℏJy (and similarly for L and S) 5b) Write |j = 5/2, mj= 3/2〉as a sum over |l = 2, ml〉|s = 1/2, ms〉states using Clebsch-Gordon coefficients. [5 points] Hints: ml can take values of -2,-1,0,1,2 and ms can take values of -1/2, +1/2, with the restriction that mj=3/2=ml+ms The only two combinations that satisfy mj=3/2=ml+ms are ml=2, ms=-1/2 and mj=1 and ms=+1/2. Use the j=5/2 and mj=3/2 vertical line in the CG table to get the appropriate CG coefficients.