Uncertainties & Total Angular Momentum

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The discussion revolves around calculating an uncertainty quantity using total angular momentum operators in the x, y, and z directions, focusing on their commutation relations. The user attempts to apply the commutator of the angular momentum operators to an eigenstate |m> of J(z), leading to the equation [J_x, J_y]|m> = iħ J_z|m> = iħ m|m>. There is uncertainty about whether this approach is correct and how to proceed further. The user acknowledges a mistake in the notation, clarifying that the correct ket is |m> instead of |n>. The thread seeks guidance on the proper methodology for addressing uncertainties in angular momentum.
Sekonda
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Hey,

My question is on determining an 'uncertainty' quantity using total angular momentum operators in the x,y and z directions where we know the commutation relations between the x,y and z directions of the total angular momentum operators.

Uncertainty_Q.png


I'm not really sure where to go with this at all, I let the commutator given act on a state |m> i.e. an eigenfunction of J(z)

[\hat{J_{x}},\hat{J_{y}}]|m>=i\hbar\hat{J_{z}}|n>=i\hbar m|m>

So the commutator must equal i*hbar*m, right? Anyway I'm not sure if this is even a correct way to begin, but it should be pretty straightforward however I haven't really come across a question like this before.

By the way I replaced subscripts 1,2,3 with x,y and z repsectively.

Thanks for any help!
SK
 
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Woops, the equation should read:

Sekonda said:
[\hat{J_{x}},\hat{J_{y}}]|m>=i\hbar\hat{J_{z}}|m>=i\hbar m|m>

not 'n' ket but 'm' ket.

Sorry...

SK
 

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