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I Scientific American Entanglement Movie

  1. Sep 29, 2016 #1

    Zafa Pi

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    Scientific American created a short movie purporting to explain entanglement and the Bell experiment at:
    http://www.scientificamerican.com/video/quantum-entanglement-the-movie-2012-01-30/

    The part that interests me is near the end when explaining what is possible with entangled photons, which I believe is fatally flawed. I am wondering if the QM community here agrees.
     
  2. jcsd
  3. Sep 29, 2016 #2

    Doc Al

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    I haven't watched the video, but the description states "In this dramatized film, Scientific American editors George Musser and John Matson try to fool a colleague into thinking their brains are quantum-entangled."

    Are you sure it's meant to be serious? What claim are they making that you question?
     
  4. Sep 29, 2016 #3

    Zafa Pi

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    It is meant to be serious. The claim starts at 7:20.
     
  5. Sep 30, 2016 #4

    Strilanc

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    Here's a youtube link (the site you linked to has overlay spam):



    It's just a framing device for the video. They build up from "look we're doing the same thing!" to being forced (and failing) to violate Bell inequalities as a skeptical colleague keeps not believing them.

    The worst mistake is they basically say quantum systems pass the CHSH test 100% of the time. That's wrong. The actual pass rate is at most 85-ish percent of the time. If they wanted 100% quantum success then they should have used a more complicated test, like the mermin-peres magic square game.

    Also I don't like that they implied that entanglement was a permanent state of affairs, as if you could keep re-using entanglement to pass tests again and again. But... after fixing that CHSH-100% issue, I think the more pressing issue would have been improving the cinematography. The pacing and the acting leave a lot to be desired.
     
  6. Sep 30, 2016 #5

    Zafa Pi

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    Exactly, "the CHSH test 100% of the time" was my concern. It violates Tsirelson's inequality. To set it right for the video it becomes cumbersome because they would then need to show that without QM 75% is max. Thank you for validating.

    What you call the "mermin-peres magic square game", which I've heard called by the more colorful "quantum pseudo-telepathy" might actually be easier to present correctly due to the lack of difficulties that arise from the 85% vs 75% issue. It is quite spectacular, and makes for a great math problem that no one (unless s/he knows of a QM solution) can solve.

    Also the "re-using entanglement" is a bother, yet is easily fixed by continually using fresh pairs of entangled photons.

    Work up a sophisticated video critique and send to the Newyorker. :-)
     
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