Entanglement in QM interpretations

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Discussion Overview

The discussion revolves around the relationship between quantum mechanics (QM) interpretations and the concept of entanglement, particularly focusing on how deterministic theories can account for entanglement and instantaneous effects across vast distances. Participants explore various interpretations of QM, including Bohmian mechanics, and their implications for determinism and non-locality.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants express confusion about how deterministic theories can explain entanglement and instantaneous effects over large distances.
  • It is noted that deterministic theories belong to classical mechanics (CM), while entanglement is a feature of quantum mechanics (QM), suggesting a fundamental difference between the two.
  • Some argue that deterministic interpretations of QM, such as Bohmian mechanics, provide a non-local mechanism for entanglement through a universal pilot wave.
  • Others challenge the notion that deterministic interpretations imply instantaneous effects, suggesting alternatives like superdeterminism or many-worlds interpretations.
  • Concerns are raised about the lack of a clear deterministic mechanism for entanglement in various interpretations, with some asserting that Bohmian mechanics offers such a mechanism through the deterministic Schrödinger equation.
  • Participants discuss the analogy of Newtonian gravity, questioning whether it provides a clear mechanism for action at a distance, similar to the issues faced in QM interpretations.
  • There is a mention of the limitations of current interpretations and a desire for a more fundamental theory that could unify various aspects of QM and potentially incorporate gravity.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how deterministic theories relate to entanglement. Multiple competing views remain, particularly regarding the implications of determinism and the nature of non-locality in QM interpretations.

Contextual Notes

Some discussions highlight the dependence on definitions of determinism and non-locality, as well as the unresolved nature of certain mathematical and conceptual aspects of QM interpretations.

selfsimilar
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TL;DR
How can deterministic theory explain entanglement.
Going through QM interpretations theories I have a hard time understanding how entanglements fit in these theories. How can a deterministic theory explain instantaneous effects billions( or maybe trillions) of light years away. Can somebody clarify the issue for me?
 
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Determistic theory belongs to classical mechanics CM. Entanglement belongs to QM. I am afraid that QM is not explained by CM. CM is explained by QM in a kind of limit.
 
anuttarasammyak said:
Determistic theory belongs to classical mechanics CM. Entanglement belongs to QM. I am afraid that QM is not explained by CM. CM is explained by QM in a kind of limit.
But aren't QM interpretations which are suppose to be deterministic claim to explain QM.
 
Maybe I don't catch what you would like to mean. Could you show me some example or explanations on Deterministic QM Interpretations you find ?
 
selfsimilar said:
TL;DR Summary: How can deterministic theory explain entanglement.

Going through QM interpretations theories I have a hard time understanding how entanglements fit in these theories. How can a deterministic theory explain instantaneous effects billions( or maybe trillions) of light years away. Can somebody clarify the issue for me?
The experimental evidence shows that locally realistic theories are impossible. Any realistic interpretation of QM, such as Bohmian Mechanics, is non-local. There is a universal pilot wave that enables correlations at a distance - or, at least, that's what it amounts to.
 
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selfsimilar said:
TL;DR Summary: How can deterministic theory explain entanglement.

Going through QM interpretations theories I have a hard time understanding how entanglements fit in these theories. How can a deterministic theory explain instantaneous effects billions( or maybe trillions) of light years away. Can somebody clarify the issue for me?
Deterministic theories (in the sense of having still some hidden variables that determine everything) that are allowed by Bell's theorem are non-local theories (or superdeterministic theories but usually these not very scientific).
 
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selfsimilar said:
TL;DR Summary: How can deterministic theory explain entanglement.

Going through QM interpretations theories I have a hard time understanding how entanglements fit in these theories. How can a deterministic theory explain instantaneous effects billions( or maybe trillions) of light years away. Can somebody clarify the issue for me?
Same question for Newtonian gravity. It is deterministic and the force acts at a distance. How does the Sun affect instantaneously the planets, which are millions of miles away?
 
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selfsimilar said:
TL;DR Summary: How can deterministic theory explain entanglement.

Going through QM interpretations theories I have a hard time understanding how entanglements fit in these theories. How can a deterministic theory explain instantaneous effects billions( or maybe trillions) of light years away. Can somebody clarify the issue for me?
Deterministic interpretations do not necessarily imply instantaneous effects. See e.g. superdeterminism or many-worlds.
 
martinbn said:
Same question for Newtonian gravity. It is deterministic and the force acts at a distance. How does the Sun affect instantaneously the planets, which are millions of miles away?
To my knowledge that is why general relativity was invented and it says gravity is not instantaneous.
 
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  • #10
Morbert said:
Deterministic interpretations do not necessarily imply instantaneous effects.
That was my complaint. Not only that, but non of the interpretations show any thing remotely as to the deterministic mechanism for entanglement.
 
  • #11
selfsimilar said:
Not only that, but non of the interpretations show any thing remotely as to the deterministic mechanism for entanglement.
I don't follow. Even if a deterministic interpretation does not imply instantaneous action at a distance, entanglement still obtains, and would be explained by dynamics and earlier conditions
 
  • #12
selfsimilar said:
That was my complaint. Not only that, but non of the interpretations show any thing remotely as to the deterministic mechanism for entanglement.
That's not true. Bohmian mechanics gives a deterministic mechanism for entanglement. The key part of this mechanism is the Schrödinger equation, which is deterministic.

Other interpretations also use this deterministic mechanism, but some of them are not entirely deterministic, because, in addition to the deterministic Schrödinger equation, they also postulate some fundamentally non-deterministic elements. Bohmian mechanics does not postulate any fundamentally non-deterministic elements, so it's completely deterministic. But all interpretations are at least partially deterministic by using the Schrödinger equation, and the deterministic Schrödinger equation is one of the key parts of any mechanism of entanglement.
 
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  • #13
selfsimilar said:
instantaneous effects billions( or maybe trillions) of light years away.
There are no such things, so there is no reason for a theory to have to explain them.

What a theory does have to explain is correlations between measurements on entangled systems that violate the Bell inequalities. But that is not the same thing as what you describe in the quote above.
 
  • #14
Demystifier said:
That's not true. Bohmian mechanics gives a deterministic mechanism for entanglement. The key part of this mechanism is the Schrödinger equation, which is deterministic.

Other interpretations also use this deterministic mechanism, but some of them are not entirely deterministic, because, in addition to the deterministic Schrödinger equation, they also postulate some fundamentally non-deterministic elements. Bohmian mechanics does not postulate any fundamentally non-deterministic elements, so it's completely deterministic. But all interpretations are at least partially deterministic by using the Schrödinger equation, and the deterministic Schrödinger equation is one of the key parts of any mechanism of entanglement.
Demystifier said:
Schrödinger equation, which is deterministic.
in the sense of evolution . But not the particle position. Otherwise we would not have this discussion.
Demystifier said:
Bohmian mechanics does not postulate any fundamentally non-deterministic elements, so it's completely deterministic.
particle position is still determined by the magical guiding wave which amounts to a postulate but does not give clear mechanism how particles affect each other.
 
  • #15
selfsimilar said:
in the sense of evolution . But not the particle position.
In Bohmian mechanics, which is what @Demystifier was talking about, particle positions do evolve deterministically.

selfsimilar said:
particle position is still determined by the magical guiding wave
That plus the initial particle positions, yes. Note the bolded word.

selfsimilar said:
does not give clear mechanism how particles affect each other.
In Bohmian mechanics, particles do not affect each other directly. There are no particle-particle interactions.
 
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  • #16
selfsimilar said:
particle position is still determined by the magical guiding wave which amounts to a postulate but does not give clear mechanism how particles affect each other.
Would you say that Newtonian gravity gives a clear mechanism how particles affect each other?
 
  • #17
Demystifier said:
Would you say that Newtonian gravity gives a clear mechanism how particles affect each other?
certainly not, not even general relativity. QFT particle interaction I have some sympathy for, like the "virtual particle" and intuitive concept of momentum. But QM and interpretations are really awkward, that is why there is so much talk about them, just seems something missing. I am hoping for a theory that is constructed in such a way that all aspects of QM are emergent and related by a fundamental concept and so non-locality is one such important aspect/result, then such theory can be truly considered the right interpretation. And if Gravity falls out of it so much better and some fundamental constants would be icing on the cake. Ok, forget about the last two requests:smile:.
 
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  • #18
PeterDonis said:
In Bohmian mechanics, particles do not affect each other directly. There are no particle-particle interactions.
I agree. I am familiar with the general concept.
 

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