- #1
LagrangeEuler
- 717
- 20
For every operator ##A##, ##[A,A^n]=0##. And if operators commute they have complete eigen- spectrum the same. But if I look for ##p## and ##p^2## in one dimension ##sin kx## is eigen- function of ##p^2##, but it isn't eigen-function of ##p##.
[tex]p^2 \sin kx=number \sin kx[/tex]
[tex]p\sin kx \neq number \sin kx[/tex]
where
[tex]p=-i\hbar\frac{d}{dx}[/tex]
[tex]p^2=-\hbar^2\frac{d^2}{dx^2}[/tex]
[tex]p^2 \sin kx=number \sin kx[/tex]
[tex]p\sin kx \neq number \sin kx[/tex]
where
[tex]p=-i\hbar\frac{d}{dx}[/tex]
[tex]p^2=-\hbar^2\frac{d^2}{dx^2}[/tex]