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Experimental covariance curve

  1. Dec 26, 2012 #1
    Some experimental covariance curve for entangled photons gives abs(Cov(0)) less than 1.
    For example : Violation of Bell inequalities by photons more than 10km apart by Gisin's group in Geneva.

    Does this mean that experimentally we cant predict with certainty in this case ?

    In order to explain that curve I made a quantum calculation that leads to Cov(theta) equals -7/8*cos(theta) but i find it a bit weird and dont know if i can put it in this forum.
     
    Last edited: Dec 26, 2012
  2. jcsd
  3. Dec 26, 2012 #2

    mfb

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    Knowing one value, we cannot predict the other with 100% certainty in this case, right.
     
  4. Dec 26, 2012 #3
    However standard qm gives -cos(theta) and hence predict with certainty at theta equals 0.

    So is the theory with something to be changed in order to get nearer to the experimental result or is it the experiment which is not accurate enough ?
     
  5. Dec 26, 2012 #4

    mfb

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    I don't know which specific experiment you mean, but no experiment is perfect. You always have uncorrelated background (or even background correlated in the wrong way), which reduces correlation.
     
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