Why position and momentum operators are both continuous spectrum while angular momentum is discrete?
1584
Why does spin have a discrete spectrum?
88926
Why do we use operators in quantum mechanics?
41407
How to derive or justify the expressions of momentum operator and energy operator?
23115
Why is the spectrum of the $\beta$-decay continuous?
65859
How does wave function collapse when I measure position?
49759
Proving that $i\hbar\frac{\partial}{\partial \mathbf{p}}$ is the operator of $\mathbf{x}$ in momentum space
61484
Continuously invertible operators
77245
Angular momentum squared and Hamiltonian?
71820
Intuitive explanation of why momentum is the Fourier transform variable of position?
51392
What does it mean to Fourier transform a ladder operator (in the input-output formalism)?
93865
Where does the photon orbital angular momentum go in light-matter interactions?
69031
Square of angular momentum operator in spherical coordinates
26417
Why do we use Hermitian operators in QM?
26959
Why doesn't the uncertainty principle contradict the existence of definite-angular momentum states?
81480
What is wrong with this deduction to show that within a multiplet different state has different square angular momentum?
89004
Where does the partial derivative come from in Sakurai's derivation of the momentum operator?
52935
Do eigenvectors of quantum operators span the whole Hilbert Space?