The position operator in coordinate representation is:(adsbygoogle = window.adsbygoogle || []).push({});

X_{ab}=aδ(a-b)

this is diagonal as expected

The momentum operator turns out to look like

P_{ab}=-ih∂_{a}δ(a-b)

Now, this is not supposed to be diagonal because it does not commute with X.

However it looks pretty diagonal to me.

What am I missing?

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# Coordinate representation of the momentum operator

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