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EPR statements to agree/disagree with or to comment on:

  1. Oct 24, 2005 #1

    Hans de Vries

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    1) The origin: Conservation laws → Correlation

    It’s the laws of conservation of energy, momentum, angular momentum,
    that necessitates a correlation between the outcome of separated random
    quantum processes. Specifically, the random process which is known under
    various names as the projection, the Born rule, the collapse of the wave

    e.g: The Compton scattering of a photon on an electron is governed by the
    conservation of energy and momentum, once the direction of the scattered
    photon is detected we also know the direction of the electron hit by the

    2) Bell inequalities violate the laws of conservation

    They violate the conservation laws because they consider the separated
    random quantum processes as being independent. The Bell type local
    hidden variables can not be responsible for the required correlation because
    they are merely input parameters for independent random processes while
    they should actually override the randomness of the process.

    e.g: The polarization angle of a photon is used as an input parameter when
    the photon passes a polarizing filter or a Wollaston prism. Being merely an
    input parameter is not sufficient to override the randomness of the process
    and as a consequence the laws of conservation are violated. (There is not
    enough correlation)

    3) Locality vs non-locality

    The process responsible for the correlation can either be local or non-local.
    It is difficult to disprove locality (and prove non-locality) because there is
    always a common origin, (The physical interaction between the two particles)

    4) The full path history is required for the conservation laws

    It is not sufficient to have a “last moment non-local communication” in
    order to preserve the conservation laws. In general each particle can go
    through several devices which modify direction (momentum), the angle of
    polarization, et-cetera. All these changes must be accounted for.

    e.g: If one particle is detected with spin up then the other particle must be
    detected with spin down in certain experiments to conserve the angular
    momentum. However, if a “spin-flipper” is placed in the path of one of the
    particles then both particles must be detected with the same spin. The
    history of the particle along its entire path is required.

    Regards, Hans
    Last edited: Oct 24, 2005
  2. jcsd
  3. Oct 24, 2005 #2


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    Looks pretty good to me. I am interested to hear what others say since my opinions are well known.
  4. Oct 24, 2005 #3


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    I don't think conservation laws have anything to do with this, really. Of course, it's because of the conservation of ang mom that we believe certain pairs produced in certain decays must be in (something like) spin singlet states.

    But all of this EPR/Bell stuff just takes that initial state for granted. That orthodox QM violates Bell Locality, for example, is just a fact about how QM works -- it really has nothing to do with experiment or conservation laws or anything like that.
  5. Oct 24, 2005 #4

    Hans de Vries

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    What is your alternative then? What does determine the correlations?

    The conservation laws of energy, momentum and angular momentum need
    the correlations to coexist with the quantum randomness of Born's rule.
    What else should save the conservation laws then?

    Regards, Hans
    Last edited: Oct 24, 2005
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