Sunday, June 27, 2010

You know nothing

It is common for physics grad students to remember the angular momentum operator . Many will even remember that it commutes with and we can therefore form a set of simultaneous eigenfunctions to describe a particle in angular momentum space. Some may even recall that the standard conventions yield the following eigenequations.



But do you know how to demonstrate that and are the eigenvalues for and ?

for Stache:

2 comments:

  1. I must know nothing. I thought that m was the eigenvalue of Lz by definition. But in my memory, the eigenvalue of L squared follows from the commutation relations. Right?

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  2. You can of course always renormalize the quantum numbers to make one of them whatever you wish. However you still must show that m ranges from -j to j and moves in integer steps. Of course you begin with J_z|j,m> = \mu |j,m> and J^2|j,m>=\lambda|j,m>. Then later you relate \lambda to \mu and then decide to take \mu = m which in turn forces \lambda = j(j+1)

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Keep it to Physics, please.