Show operator is diag in second basis

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Homework Statement


Show explicitly using Pauli matrices that the S2 operator is diagonal in the second basis.


Homework Equations


S2=S^{2}_{1}+S^{2}_{2}+2S_{1}S_{2}

3. The Attempt at a Solution [/b]
In the last term, 1 and 2 are supposed to be subscripts, and the two S's should be shown as a dot product.

Treat as a 2-particle system; what are they looking for? What does "in the second basis" mean? There is also a chance that the probelm statement is incorrect; in the instructor's superscripts, it's often impossible to distinguish a 2 from a z. Thanks in advance.







 
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