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In case of 3d free particle Schrodinger equation solution, the angular momentum eigenvalue L-square =l(l+1) and a free particle has a wavefunction as the superposition of all 'l'(angular momentum) states.Now the difficulty is that when I will measure the L-square, is it true that I will endup with a result L-squrae=l(l+1) even for a free particle? Can anybody measure the anguler momentum directly?
 

malawi_glenn

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you measure the angular momentum with respect to some reference point.
 
ok......but without potential how can I expect the angular momentum quantization? Is it experimentally verified that the angular momentum of a free particle is quantized?
 

malawi_glenn

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you write the plane wave as series expansion of angular momenta.

in order to measure the angular momentum of a particle you need something to make it interact with, a potential ..

but yes scattering of particles against potentials include terms for all angular momentum components of the incoming particle.
 
So when I will measure the angular momentum, I can get all the L-square with different probability..Is it true?
 

malawi_glenn

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yes.
 
So, how can I know whether this is Boson or Fermion?
 

malawi_glenn

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what has that anything to do with angular momentum?
 
but Boson or Fermion depends on it's angular momentum.
 

malawi_glenn

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no, they depend on their INTRINSIC angular momentum; The Spin.

What you and me have discussed now is a particles orbital angular momentum.
 
OK thanks and sorry for the stupidity
 
But for the same reason, why is not energy quantized?
 
Last edited:

malawi_glenn

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the energy of a free particle is the initial energy...

have you learned about scattering theory yet? If not, you might want to study it.
 
just studying....
 
what is scattering theory?
 
It is not so clear to me but I only know that this is the quantum mechanical description of scattering of some incoming particles by some scatterer (potential).
 
and I only know the partial wave method.
 

malawi_glenn

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energy is conserved in inelastic scattering, i don't know where your "why is not energy quantized?" comes from - what makes you ask such question??

use "edit" feature.
 
ok thanks..
actually my mother tongue is Bengali that's why I have some problem in English.
 

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