1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Angluar momentum J values.

  1. Jan 7, 2009 #1
    A pair of spin half particles in a bound state. Spin angular momentum operators S1 and S2. In l= 0, no orbital component, the operator for total angular momentum is J = S1+S2

    Possible ang mom states can be denoted by |J, M> where J and M are quantum numbers for J^2 and Jz respectively. Write down the two possible values of J and corresponding eigenvalues of J^2. For each J list allowed M.


    J^2 eigenvalue for a given J is J(J+1)hbar^2. The two possible values of are J=1 eigenvalue 2hbar^2 and J=0 eigenvalue 0

    Sorry long question! Why is J = 1 and J=0. Couldn't it also be J=-1? Or can S1 and S2 only be 1/2 or 0?

  2. jcsd
  3. Jan 7, 2009 #2
    you just said two spin half particles. therefore s1 and s2 are either +1/2 or -1/2
    but we add them using the addition of angular momentum theorem

    classically you just add them and the possibilities are -1,0 or 1

    quantum mechanically j takes values ranging from |s1|+|s2|,.....,||s1|-|s2||

    so if s1,s2 are either 1/2 or -1/2 then |s_i|= 1/2
    and so j ranges from 1 to 0
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Angluar momentum J values.