resource-phys-phd-qualify

Phys PhD Qualification Exam

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pdf test is here,

\[\left[-\frac{\hbar^2 \nabla^2}{2m} + v_s(\textbf{r}) \right] \psi_i(\textbf{r}) = \epsilon_i \psi_i(\textbf{r})\] \[x+y=z\]

Here is $a+b$