18.104.22.168 Solution complexsb-a
As an example of the orthonormality of the two-particle spin states, verify that is zero, so that and are indeed orthogonal. Do so by explicitly writing out the sums over and .
The inner product is by definition
or writing out the second sum explicitly
or writing out the first sum also explicitly
and noting that 0 and 0, you see that all terms are zero.