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Spins as qubits

  1. Nov 2, 2009 #1

    I'm stuck with a simple and stupid question...

    We have a spin "up" and "down" as a qubit 1 and 0 states.
    Now can we consider a state perpendicular to this basis direction as a (0+1)/sqrt(2) state?

    If not then what is the sence of the phase shift x in the state (0+exp(ix)1)/sqrt(2)?
  2. jcsd
  3. Nov 3, 2009 #2


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    An electron has spin components in the x, y and z directions where x, y and z are mutually perpendicular. These components do not commute, so knowledge of one does not represent knowledge of another.

    A photon is different, as the perpendicular component is directly related.
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