Just your average layman here, wanting to understand the whole entanglement work for the Nobel prize. Why can't the entangled pairs have a fixed spin that we don't know? How do experiments prove otherwise? My understanding is that the results in testing showed always 25% different 75% same when measuring spin of entangled electrons on two different detectors when in two different configurations. I've thought about this and you can arrive exactly at these numbers, without the instant updates and wave function collapses. I guess it would be a thought experiment as you cannot prove it, but it is completely logical. Appreciate anyone who can help me understand and perhaps point me to some articles that support the hidden variables theory still, especially after this prize was awarded. Thanks

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    $\begingroup$ theconversation.com/… $\endgroup$
    – anna v
    Dec 22, 2022 at 19:43
  • $\begingroup$ Thanks for that. Read through it but still question why hidden variables cannot exist. If they do exist, the 25% 75% results can be fully explained, if we say they have a fixed spin, opposite to each other at creation, as would be expected. Seems like they just suggest the experiments prove they do not exist. My thinking is the results are just calculated incorrectly with hidden variables, as I arrive at the QE results. $\endgroup$
    – Paul
    Dec 22, 2022 at 20:32
  • $\begingroup$ Does this answer your question? Bell's theorem for dummies, how does it work? $\endgroup$ Dec 22, 2022 at 21:51
  • $\begingroup$ @Paul keep in mind that "hidden variables cannot exist"is used in mainstream physics within the existing mainstream mathematical models of quantum mechanics, which at present are considered a good model of nature. There exist very good physicists, among them G. 't Hooft a member here , who is working on a theory that will reproduce the results of the present main stream physics mathematical models. He has answered a Bells theorem question physics.stackexchange.com/questions/48066/… $\endgroup$
    – anna v
    Dec 23, 2022 at 4:42

1 Answer 1


It's correct that you can (with a bit of care) come up with a set of hidden variables that will work for a pair of EPR-type detectors in one fixed orientation. The trick is coming up with a set of hidden variables that will match the results of quantum mechanics if your detectors are in any orientation. The reason that the results of Aspect et al. were so striking is that they managed to come up with a setup where the "orientation of the detector" was (effectively) chosen randomly why the particles were in flight from their source, making it much less plausible that there was some secret collusion between the states of the detectors and any hidden variables that might have been dictating the measurement outcomes.

For careful but accessible account of why coming up with a set of variables that work for all detector orientations is impossible, I recommend "Quantum Mysteries for Anyone" by N. David Mermin. Your local library can probably get you a copy, either via a subscription to the JSTOR service or via interlibrary loan. It's also available in Boojums All The Way Through, a collection of his papers.

  • $\begingroup$ Thanks. I'll take a look and also post my thoughts on how the test doesn't prove the absence of hidden variables in a new post. $\endgroup$
    – Paul
    Dec 22, 2022 at 22:17

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