Momentum eigenvalues and eigenfunctions

AI Thread Summary
The discussion focuses on demonstrating that the wave functions ψ_{x}, ψ_{y}, and ψ_{z} are eigenfunctions of the angular momentum operators Lx, Ly, and Lz, respectively, along with L^2. The user attempts to calculate Lz|ψ_{z}> and shows that it leads to the expected eigenvalue equation. They express concern about the explicit calculation of partial derivatives and whether their approach is correct. The calculations involve applying the angular momentum operators to the wave functions and confirming that the results align with the eigenvalue definitions. The user seeks clarification on their method and any potential oversights.
White_M
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Homework Statement



For the following wave functions:
ψ_{x}=xf(r)
ψ_{y}=yf(f)
ψ_{z}=zf(f)

show, by explicit calculation, that they are eigenfunctions of Lx,Ly,Lz respectively, as well as of L^2, and find their corresponding eigenvalues.

Homework Equations



I used:
L_{x}=-ih(y\partial/\partial z-z\partial/\partial y)
L_{y}=-ih(z\partial/\partial x-x\partial/\partial z)
L_{z}=-ih(x\partial/\partial y-y\partial/\partial x)

for solving:

L_{z}|ψ_{z}>=lz|ψ_{z}>
L_{x}|ψ_{x}>=lx|ψ_{x}>
L_{y}|ψ_{y}>=ly|ψ_{y}>


and
L^2|ψ>=l^2|ψ>

where:
L^2=L_{x}^2+L_{y}^2+L_{z}^2

The Attempt at a Solution



For instance for Lz:
ψ_{z}(r)=<r|z>=zf(r)

L_{z}|ψ_{z}>=-ih(x\partial/\partial y-y\partial/\partial x) zf(r)=lz|ψ_{z}>

Is that correct?
 
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I think they want you to "explicitly" take partial derivatives of the function z f(r) .
 
-ih (x(\partialz\\partialy f(r)+z \partialf(r)/\partialy)-y(\partialz\\partialx+z\partialf(r)\\partialx))=-ih (xz\partialf(r)\\partialy-yz \partialf(r)\\partialx)=-ih (x\partial\\partialy-y\partial\\partialx)zf(r)

Which is the same as the initial expression.

What am I missing?

Thanks
 
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