phy-521/griffiths/3.8

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2020-12-23 21:45:08 +00:00
3.8
a)
check that the eigenvalues of the hermitian operator in example 3.1 are real. show that the eigenfunctions are orthogonal.
Qf = if'
the eigenvalues are 0,+- 1, etc., which are obviously real.
pick two arbitrary eigenfunctions:
f = A exp(-i q phi)
g = A exp(-i q' phi)
<f|g> = A*A int[exp(i q phi) exp(-i q' phi)] dphi[0,2pi]
= A*A int[exp(i (q - q') phi)] dphi[0,2pi]
= A*A [i(q-q')]^-1 [exp(i(q-q') phi)]|[0,2pi]