- #1
tarkin2
- 2
- 0
Homework Statement
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Parts (c) and (f) are the ones I'm having trouble with;
Homework Equations
The Attempt at a Solution
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For (c), I assume the problem is meant to involve using the result from part (b), which was H = g(J2 - L2 - S2)/2 .
I was trying just to do it by first showing that H commutes with J2 , and then was going to do the same for L2 and S2, and also I would have just stated that Jz commutes with J2 and therefore also with the Hamiltonian.
But I wasn't entirely sure how to show that this. I tried:
[H, J2] = (g/2) [ J2 - L2 - S2 , J2 ]
=(g/2) ([ J2 , J2] - [L2, J2 ] - [S2 , J2 ])
= (g/2) (0- [L2, J2 ] - [S2 , J2 ])
But I wasn't sure how to show that these last 2 terms are 0. Also I assume this isn't the best method, because it doing it this way you would be answering part (f) in the process. Is there a different method, for only 3 marks?
Any help is appreciated