
#1
Feb2512, 08:31 PM

P: 21

We know from classical mechanics that angular momentum [itex]L = r \times p[/itex] depends on your choice of origin. My question is: How does this work quantum mechanically? We know we get certain eigenvalues, but does this apply only in a certain choice of origin? How do we calculate angular momentum at some other point? I had a similar problem concerning torque on a magnetic dipole, [itex]\tau = \mu \times B = r \times F[/itex]. About what point do we measure the moment arm?
Do we just assume our origin is at the "center" of the orbit? Thanks for the help. 



#2
Feb2612, 04:40 AM

Sci Advisor
P: 3,376





#3
Feb2612, 07:46 AM

P: 343

In quantum mechanics, orbital angular momentum usually describes electron orbitals, where orbitals are located in an atom. When we regarding to an atom, I don't think choosing an arbitrary axis, say the tree trunk outside, would mean any thing to solving problems.
Therefore, it has no necessity to specify the axis, since we all know what we are referring to 



#4
Feb2612, 04:29 PM

P: 21

Orbital Angular Momentum Origin
Yeah, that's what I was thinking, but just wanted to make sure since I couldn't find it explicitly stated anywhere. Thanks!



Register to reply 
Related Discussions  
Angular Velocity and Spin/Orbital Angular Momentum of Jupiter  Astrophysics  2  
orbital angular momentum  Chemistry  3  
Orbital angular momentum of O2  Atomic, Solid State, Comp. Physics  5  
Angular momentum and orbital angular momentum problems  Introductory Physics Homework  3  
orbital angular momentum  Quantum Physics  10 