Why don't non-Hermitian operators with all real-eigenvalues correspond to observables?
26417
Why do we use Hermitian operators in QM?
141376
Why the dipole interaction term in the Hamiltonian has all diagonal elements to be zero in the energy eigenbasis?
94717
Systems in quantum mechanics solved by ladder operator method
139993
Quantum systems without a classical analogue?
26959
Why doesn't the uncertainty principle contradict the existence of definite-angular momentum states?
95481
The set of self-adjoint operators over a Hilbert space doesn't form a lattice
52935
Do eigenvectors of quantum operators span the whole Hilbert Space?
70455
Why are all nonzero eigenvalues of the skew-symmetric real matrices pure imaginary?
54668
Proof for the completeness of eigenfunctions of a self-adjoint operator
92744
These two operators commute...but their eigenvectors aren't all the same. Why?
29174
Trouble with operator-sum representation of a quantum operation
7965
Why isn't the eigenclass equivalent to self.class, when it looks so similar?
75536
every eigenvalue of $T$ has only one corresponding eigenvector up to a scalar multiplication
78075
Why can I apply $HS^\dagger$ and then measure in the computational basis to measure $Y$?
117499
Aufbau principle in modern quantum theory
130259
Is the S-Matrix the only quantum field observable?
123424
Must eigenvector be real?