Homework Statement [/b]
The attempt at a solution[/b]
I have done the first bit but don't know how to show that phi(r,t) is a solution to the equation of motion.
Relationship: it's a postulate of QM that every dynamical observable is represented by a linear hermitian operator.
A*A ket(n) = ? but not sure what will be on the right hand side
Q: Using Dirac notation, show that if A is an observable associated with the operator A then the eigenvalues of A^2 are real and positive.
Ans: I know how to prove hermitian operators eigenvalues are real:
A ket(n) = an ket(n)
bra(n) A ket(n) = an bra(n) ket(n) = an
[bra(n) A ket(n)]* =...