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Quantum spreading of polarization

  1. Feb 3, 2010 #1


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    After we measure the position of a particle fairly sharply, it “spreads out” or the uncertainty grows according to the Heisenberg uncertainty principle. After we measure the polarization of a photon, does it spread out, too? If not, why not? If so, how fast?
    Jim Graber
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  3. Feb 3, 2010 #2


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    The polarization, once known, does not independently evolve with time (other than continuing oscillation). There will be non-commuting polarization elements which will become completely uncertain as a result of the initial measurement. So if you measure photon polarization to be at 0 degrees, in principle you could measure it later and see it at the same polarization (assuming travel in a vacuum).
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