Talk:Quantum nonlocality
From Wikipedia, the free encyclopedia
| |||||||||||||
 | Text and/or other creative content from this version of Nonlocality was copied or moved into Quantum nonlocality with this edit. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists. |
| This is the talk page for discussing improvements to the Quantum nonlocality article. This is not a forum for general discussion of the subject of the article. |
Article policies
|
| Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
Archives (index): 1, 2Auto-archiving period: 3 months  |
 | This  level-5 vital article is rated C-class on Wikipedia's content assessment scale.It is of interest to the following WikiProjects: | ||||||||||
| |||||||||||
.jpg){kind=small}
"Local Realism"
It looks like Wikipedia no longer has an article on "local realism." Should that language in this article be reworded? Yoderj (talk) 15:52, 6 May 2024 (UTC)
- Local realism exists and redirects to Principle_of_locality#Quantum_mechanics. Johnjbarton (talk) 15:59, 6 May 2024 (UTC)
More Copenhagen OR
The section "Einstein, Podolsky and Rosen" says
However, according to the Copenhagen interpretation, Alice's measurement causes the state of the two particles to collapse,...
but this claim is unsourced. Section continues with the example then says
Schrödinger referred to this phenomenon as "steering".
citing a reliable source. That source says nothing about "Copenhagen", nor Bohr, Born, or Heisenberg the folks for whom "Copenhagen interpretation" was named. The assertion that the claims in this section are "Copenhagen interpretation" is unsourced. The only source makes reference to Schrodinger who refers to the overall issue as steering.
Bohr, the head of the institute in Copenhagen, never used "collapse" in any interpretation of an experiment. The connection between "collapse" and "Copenhagen interpretation" is original research that appears in many Wikipedia articles. Johnjbarton (talk) 15:20, 20 March 2025 (UTC)
- The sentence you object to is completely uncontroversial: measurement causes collapse in orthodox quantum mechanics. The less we talk about Copenhagen the better, so I've simply eliminated the mention to it.
- The sentence you inserted to replace it is incorrect: you are claiming that steering is merely wavefunction collapse, and this is not true, and also not supported by the source. Tercer (talk) 09:35, 21 March 2025 (UTC)
Everett local realism loophole is missing
History
What a mess. Look, it *should* be simple! Don't use symbols in an equation before you define/explain them. Don't use two or three DIFFERENT notation systems. |0>A IS NOT EXPLAINED. (same with the symbols 1 and B in the same equation). Then, don't switch (for zero reason, with zero explanation) to |+>A (etc.) as if there's ANY meaning in the change in notation. And then we have |±> added as if that's necessary or useful. It is neither! And that's not all. Oh, no. Let's add |←> (and 3 other arrows) without explanation too! Here's my attempt at cleaning it up, but I'm 30 years rusty on this stuff. Using the assumptions of QM, the state operator |ΨAB> can be expressed as a sum of two terms each a product of two terms. The term |0>A represents the 0 state of the particle A, similarly for the 1 state and for particle B. The equation [I'll not try to duplicate it but the rubbish starting at the 2nd (moving left to right) '=' sign, including the following line should be removed.] indicates that the states of A and B are correlated and binary. If A is in its '0' state then B is in its '1' state and vice versa. The equation expresses the statement that the state of the system is FULLY described by the 4 states present. (I'm not sure if it's correct to say |0>A is a state? maybe substate? component?, IDK). Then it claims that A is measured in the basis {.,.} and B exists in "one of the states" {.,.}. (I've left out the symbols inside the curly braces for brevity.) Look, if {.,.} is a basis set then it doesn't represent two states. That sentence should be "However, according to textbook quantum mechanics, Alice's measurement causes the state of the two particles to collapse. This means that if Alice performs a measurement of spin in the z-direction; that is, with respect to the basis {|0>A or |1>A}, then Bob's system will be left in one of the states |0>B or |1>B. NOTE That this is the first time "spin" is mentioned! ... Why bring spin in at this late date? Sigh. Why in the world would it seem reasonable to use 0&1 for one axis and +&- for another? Yeah, a mess. Needs a rewrite, imho.~2025-39446-09 (talk) 08:20, 28 December 2025 (UTC)