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!

Finding spin state.

  1. Sep 9, 2012 #1
    1. The problem statement, all variables and given/known data
    [itex] |\psi >=a|z>+b|-z> [/itex]
    find [itex] <S_x > [/itex]
    3. The attempt at a solution


    So I just need to find
    [itex] <S_x>=({|<x|\psi >|}^2-{|<-x|\psi>|}^2)\frac{\hbar}{2} [/itex]
    right
     
  2. jcsd
  3. Sep 9, 2012 #2

    TSny

    User Avatar
    Homework Helper
    Gold Member

    Yes, that will get you the answer. If you know the matrix representations of [itex] S_x [/itex], [itex] |z> [/itex], and [itex] |-z> [/itex], then you can also just calculate directly [itex] <S_x>=<\psi |S_x|\psi > [/itex].
     
  4. Sep 9, 2012 #3
    An easy way to do this problem is to write Sx in terms of the raising and lowering operators. The expectation values of both the raising and lowering operators should be obvious.
     
  5. Sep 9, 2012 #4
    ok thanks for the posts.
    If I know what |+x> is. Can I construct |-x> by creating coefficients so that the probability of measuring spin up in the +x and -x equals 1.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Finding spin state.
Loading...