Is expectation value of the Hamiltonian always the energy?
42186
When is the Hamiltonian of a system not equal to its total energy?
54548
Expectation value for $\frac{1}{r}$ in the $|nlm\rangle$ state of hydrogen
156863
Uncertainty Principle for a Totally Localized Particle
121389
Why is quantum mechancis is not content with symmetric operators, but wants self-adjoint operators?
128875
Expectation values of the position operator is equal to zero in case of even potentials?
41407
How to derive or justify the expressions of momentum operator and energy operator?
156019
Expectation formula of an integrable random variable
29728
Does the vacuum in QFT have nonzero energy or not?
28062
Something special about energy eigenstates when it comes to time evolution?
57051
Why does Quantum Field Theory use Lagrangians rather than Hamiltonians?
129170
Deriving the expectation of $[\hat X,\hat H]$
90716
Conservation of energy and wavefunctions
145136
When can we interchange the derivative with an expectation?
36380
Why not use the Lagrangian, instead of the Hamiltonian, in nonrelativistic QM?
141376
Why the dipole interaction term in the Hamiltonian has all diagonal elements to be zero in the energy eigenbasis?
51122
Lagrangian of Schrodinger field
118195
How does one prove that $e$ exists?