Quote by Dickfore
They are not. For example:
[tex]
\langle x  p \rangle = \frac{1}{(2\pi \hbar)^{1/2}} \, \exp{\left(\frac{i}{\hbar} \, p \, x\right)} \neq 0
[/tex]

Can you specify the eigenvectors of position and momentum? I just started learning it and I am not familiar with it.