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Hidden variables - Bell - The Law of Malus?

  1. Sep 6, 2013 #1

    Zafa Pi

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    Invariably in the lay literature when it comes time to show that EPR hidden variables are incompatible with QM, Bell's Theorem is invoked (e.g. Greene's "Fabric of the Cosmos", Zeilinger's "Dance of the Photons", Rosenblum's "Quantum Enigma", ...).

    I don't see why a simple application of Malus' Law (old as the hills) doesn't accomplish it, to wit:
    If we have a zillion vertically polarized photons beamed into a polarized lens whose axis is rotated 30° to the right of vertical (R30°), then about 3/4 get thru. So that 3/4 have been tagged (hidden) with the instruction to pass thru R30°. The same goes for L30°. Thus at least 1/2 of the zillion have been tagged to go thru both. But Malus tells us that only 1/4 go thru both.

    I haven't found a thread that mentions this. Nor do I see why this doesn't refute hidden variables.
    Admittedly to refute local realism one seems to need something like Bell's Theorem with entangled pairs.
  2. jcsd
  3. Sep 6, 2013 #2

    Zafa Pi

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    I'm sorry I didn't think this thru. Once a tagged photon passes thru R30° it's no longer vertically polarized so there is no tag for L30°.
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