How to calculate $\langle 1/r^2 \rangle$ for hydrogen using Hellmann-Feynmann Theorem? Wikipedia is wrong, isn't it?
62387
What are independent parameters in Hellmann–Feynman theorem?
151721
Uhlmann's Theorem: proof of $\text{tr}(A^{\dagger} B) = \langle m | A \otimes B |m\rangle $
128710
Prove that $\langle a^n \rangle \bigcap \langle a^k \rangle = \langle a^{lcm (n,k)} \rangle$
25262
Why can we apply the $E=hf$ equation for electrons?
45559
Why we use $L_2$ Space In QM?
134687
Is there a more elegant way of proving $\langle (1,2)(3,4), (1,2,3,4,5) \rangle = A_5$
156467
Does $\langle\Omega|\mathrm{e}^{\mathrm{i}Px}=\langle\Omega|\mathrm{e}^{\mathrm{i}0x}$? $(\langle\Omega| =$ ground state of the interacting theory)
103870
$3.\lim_{n\to\infty}\langle x,e_n\rangle=?$
77742
Queries about rotational groups $\mathrm{SO}(3)$ and $\mathrm{SU}(2)$ in QM
83183
Why is $\langle x| x' \rangle=\delta(x-x')$?
90818
Can't Prove formula from Sakurai's Modern QM @ Perturbation Theory
77758
Calculate the uncertainty in velocity of electron
60946
Find the matrix of $\langle f, g \rangle = \displaystyle\int_0^1 f(t) g(t) \, \mathrm dt$ with respect to the basis $\{1,t,\dots,t^n\}$
14274
Calculating de Broglie wavelength
112625
Reduced mass in quantum physics (Hydrogen Atom)
79647
Where does the term $|\psi\rangle\langle\psi|$ come from while calculating the expectation value?
87328
Expectation of momentum in the bound state