Since we know that Anticipating the result, let
Form the raising and lowering operators and
Find the commutators
Frompart (a) we know that We now ask what is the eigen-
value of for the states
So, these states have the same eigenvalue of Now, examine the eigen-
value of for these states:
In (S.5.23.3) we see that has the effect of raising or lowering the
of the states so that
where are the corresponding coefficients. As determined above, we
knowthat so cannot be applied indefinitely to the state
there must be an such that
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