# Angular momentum Question

1. Mar 7, 2005

### Ed Quanta

Show that the following superposition state in the |l,m1;ms> basis:-(2/3)^1/2|1,-1;1/2> + (1/3)^1/2|1,0;-1/2> is an eigenstate of J^2 and L * S and determine the corresponding eigenvalues.

I have no clue how to start this. Any help would be appreciated.

2. Mar 7, 2005

### dextercioby

How do you determine the action of the operators
$$\hat{\vec{J}}^{2} ,\hat{\vec{L}}^{2},\hat{\vec{S}}^{2}$$

on any eigenstate...?

Daniel.

3. Mar 7, 2005

### Tom Mattson

Staff Emeritus
First note that:

$$\hat{\mathbf {J}}^2=\hat{\mathbf {J}} \cdot \hat {\mathbf {J}}=(\hat{\mathbf {L}} + \hat{\mathbf {S}}) \cdot (\hat{\mathbf {L}} + \hat{\mathbf {S}}) =\hat{\mathbf {L}}^2 + \hat{\mathbf {S}}^2+2 \hat{\mathbf {L}} \cdot \hat{\mathbf {S}}$$

Hit each term of your state vector with it.

edit: Bloody dexter, his LaTeX is faster than mine. :tongue2:

Last edited: Mar 7, 2005
4. Mar 7, 2005

### dextercioby

I used "hats" for operators,that's a reason for envy... :tongue:

Daniel.

P.S.BTW,i resent the boldface notation of vectors... :yuck: :tongue2:

Last edited: Mar 7, 2005
5. Mar 7, 2005

### Tom Mattson

Staff Emeritus
Nothing a quick edit can't fix. Now my operators don't have cold heads. :rofl:

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