Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Spin Rotation

  1. Jul 8, 2010 #1
    Hi there!
    If I have an electron in the spin state |+> and I rotate it by an angle of 360°, then the state becomes -|+>. Now, if I want to find the probability of measuring the spin up, I have:
    P(|+>)=<+|(-|+>)=-1
    So after a rotation of 360° I have a negative probability??
     
  2. jcsd
  3. Jul 8, 2010 #2
    Ok.. I found the error!! I have to consider the square of -1 which is 1... really a stupid error :blushing:
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook