Talk:Bell's theorem

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A possible mistake?

Written by the author - A₀ A₁ + A₀A₃ + A₂A₁ - A₂A₃ . Obviously, the following equality is true: (A₀ + A₂)A₁ + (A₀ - A₂)A₃ etc. But the result of ONE MEASUREMENT can be ONLY 2 parameters. For example, A₀ and A₃ (if they have "heads" by flipping a coin for this ONE measurement). A₂ and A₁ are not determinated in this measure and are INDETERMINATE. Then what is it (A₀ + A₂) and (A₀ - A₂) - is unclear... Further construction is collapsing. Apparently, it would immediately move on to the average values and write a chain of equalities for them? 144.206.128.253 (talk) 18:16, 1 October 2024 (UTC)[reply]

In the text, uppercase letters refer to measurement results, while lowercase letters stand for the hidden properties. By assumption, the hidden properties exist whether or not they are measured. So, we can manipulate the lowercase variables by the regular rules of algebra however we like, without worrying about them being "indeterminate". The whole point is to deduce the consequences of that assumption and then show that those consequences conflict with the predictions of quantum mechanics. XOR'easter (talk) 19:00, 1 October 2024 (UTC)[reply]

Yes... Clearly.

Thanks. 144.206.128.253 (talk) 13:42, 2 October 2024 (UTC)[reply]

Recent review

I was surprised that this review was not cited.

Wharton, K. B., & Argaman, N. (2020). Colloquium: Bell’s theorem and locally mediated reformulations of quantum mechanics. Reviews of Modern Physics, 92(2), 021002.

Among many topics it mentions Everett's model, the subject of recent edits. Johnjbarton (talk) 17:20, 18 October 2024 (UTC)[reply]

Article is self contradictory re locality

Intro says experimental results are incompatible with local hidden variable theories, but Manyworlds section says Bell's doesn't apply and it is a dynamically local theory. This is clearly inconsistent with the intro. Suggest intro be changed to "*most* local hidden variable theories" Joncolvin (talk) 16:48, 31 October 2024 (UTC)[reply]

No. Hidden worlds don't seem to count as "hidden variables". So all local hidden variables are incompatible. Johnjbarton (talk) 17:16, 31 October 2024 (UTC)[reply]

The MWI (or rather, all the various versions of it proposed over the years) is not a hidden-variable model. In a hidden-variable model, either a wavefunction is a probability distribution over the true physical states, or the hidden variables exist in addition to the wavefunction. In MWI, the wavefunction is physical reality. XOR'easter (talk) 22:15, 31 October 2024 (UTC)[reply]