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

Rotation matrix for a Bloch sphere

  1. Jun 23, 2011 #1


    User Avatar
    Gold Member

    Reading about the general rotation of a single qubit, a rotation of [itex]\theta[/itex] in the horizontal plane and [itex]\phi[/itex]) in the vertical plane, is given as the matrix
    V( [itex]\theta[/itex] , [itex]\phi[/itex]) =

    cos([itex]\theta[/itex]/2) .................-i[itex]e^{-i \phi}[/itex] sin([itex]\theta[/itex]/2)

    -i[itex]e^{i\phi}[/itex] sin([itex]\theta[/itex]/2)...........cos([itex]\theta[/itex]/2)

    (The dots are just spacing.)
    Which would make sense to me except that I do not understand why the 1/2 factor for the angle in the horizontal plane is there. Could someone explain that for me? Thanks.
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted

Similar Discussions: Rotation matrix for a Bloch sphere
  1. Matrix in Rotation (Replies: 2)

  2. Rotational Matrix (Replies: 5)

  3. Rotation matrix (Replies: 4)