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Homework Help: Question on spin 1/2 states in arbitrary direction

  1. Feb 29, 2016 #1
    1. The problem statement, all variables and given/known data


    The problem is given above. I am struggling on the first two parts, where I am tasked with finding gamma and beta.

    2. Relevant equations

    For spin one half states in arbitrary directions, I know that psi = a*|n;+> + b*|n;-> .

    |n;+> = cos(theta/2)|+> +sin(theta/2)*ei*phi|->

    |n;-> = -sin(theta/2)e-i*phi|+> + cos(theta/2)|->

    3. The attempt at a solution

    I have attached my attempt at a solution. I am not sure what I am doing wrong at this point. Any help for the problem would be greatly appreciated :)

    Attached Files:

  2. jcsd
  3. Mar 1, 2016 #2


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    Homework Helper

    There are multiple mistakes in your calculation. I would suggest that you start over again from the first step by first normalizing the given ##|\psi\rangle##.
  4. Mar 1, 2016 #3
    I ended up getting the solution. I was making a mistake by splitting it up into |n;+> and |n;->. Instead, I factored out a phase and then normalized the whole thing. The answer came fairly quickly from there. Thanks.
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