Might be trivial, but: In deriving it, I don't understand how the minus sign comes in to establish the [H,A] commutator. (it seems to me that both partial derivatives of ψ should come out positive)(adsbygoogle = window.adsbygoogle || []).push({});

For example, in

http://www.tcm.phy.cam.ac.uk/~bds10/aqp/handout_operator.pdf

on page 5.

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# Ehrenfest theorem

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