Hello, sorry I am new to this forum, I hope I found the right category. I have a question about the momentum operator as in Sakurai's "modern quantum mechanics" on p. 196(adsbygoogle = window.adsbygoogle || []).push({});

If I let

[tex] 1-\frac{i}{\hbar} d\phi L_{z} = 1-\frac{i}{\hbar} d\phi (xp_{y}-yp_{x})[/tex]

act on an eigenket [itex]| x,y,z \rangle [/itex]

why do I get [itex]| x-yd\phi,y+xd\phi,z \rangle [/itex]

and not [itex]| x+yd\phi,y-xd\phi,z \rangle [/itex] ,

with the momentum operators

[tex] p_{x}=\frac{\hbar}{i}\frac{\partial}{\partial x} , p_{y}=\frac{\hbar}{i}\frac{\partial}{\partial y}[/tex]

Thanks for your help!

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# Homework Help: Orbital angular momentum operator

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