Non locality of quantum mechanics

Click For Summary

Discussion Overview

The discussion revolves around the implications of Bell's theorem in quantum mechanics, particularly focusing on local hidden variable theories and the concept of non-locality. Participants explore various interpretations and implications of quantum entanglement, measurement, and memory, considering both theoretical and philosophical aspects.

Discussion Character

  • Debate/contested
  • Exploratory
  • Conceptual clarification

Main Points Raised

  • Some participants propose that a local hidden variable theory could explain Bell's theorem by suggesting that memories of measurements could be modified, leading to perceived correlations.
  • Others argue that adopting such a theory would require abandoning realism, as it would imply a non-realistic interpretation of quantum mechanics.
  • A participant suggests that detectors could record measurements in a physical manner, such as drilling holes in steel, to illustrate the concept of memory and measurement correlation.
  • There is a discussion about the possibility of distant regions remaining in superposition until they meet, at which point their states could adjust to satisfy Bell's theorem.
  • Some participants question whether the states of the particles could be fully defined before they meet, suggesting that memories and states could be rewritten after the fact.
  • One participant introduces the idea that fundamental space might not adhere to Euclidean-like topology, proposing concepts like tiny wormholes or higher-dimensional strings connecting entangled particles.
  • Another participant emphasizes the lack of proven interpretations of quantum mechanics, stating that no interpretation has been experimentally validated, and all interpretations remain speculative.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the implications of Bell's theorem and the nature of quantum states. There is no consensus on whether particles have defined states before measurement or how memory affects the interpretation of quantum mechanics.

Contextual Notes

Limitations include the speculative nature of the interpretations discussed, the dependence on definitions of realism and locality, and the unresolved status of various mathematical and theoretical claims related to Bell's theorem.

entropy15
Messages
38
Reaction score
0
Can we have a local hidden variable theory explanation for Bells theorem?

The outcomes of the mesurement (measuring the electron spin of an entangled electron pair as Red or Green) can be random initially without any correlation at all.

But by the time we compare the results of the two measurements, our memories could be modified such that we remember having made a particular of measurements which had correlation.

Would not such a explanation get rid of the non locality of quantum mechanics?
will have to give up our idea of a consistent memory for this.
 
Physics news on Phys.org
will have to give up our idea of a consistent memory for this.
That means, this theory will be non-realistic. This is indeed a possible interpretation of the Bell theorem.

The Bell theorem says that you can not have all of these at once:
- realism
- locality
- casuality
- Euclidean-like topology of space

You must sacrifice at least one of these. You've decided to give up on realism. That is one possible explanation.
 
entropy15 said:
Would not such a explanation get rid of the non locality of quantum mechanics?
will have to give up our idea of a consistent memory for this.

You would have to give up a lot more than just a consistent memory. The detector could, for example, record its findings by drilling a hole in a piece of hardened steel whenever it makes a spin-up measurement; we then could bring the two pieces of steel together in a machine that sounds a loud alarm if two holes ever line up.
 
haael said:
- Euclidean-like topology of space

How can it be explained by abondoning Euclidean-like topology of space?
 
You would have to give up a lot more than just a consistent memory. The detector could, for example, record its findings by drilling a hole in a piece of hardened steel whenever it makes a spin-up measurement; we then could bring the two pieces of steel together in a machine that sounds a loud alarm if two holes ever line up.
If I understand entropy15's intention well, then he thinks of a theory where distant regions remain in some kind of superposition until they meet, when they adjust themselves to satisfy the Bell theorem.
That means, two distant observers (or two distant steel bars) that record two distant experiments with entangled particles, don't have a fully defined state until they meet. Then, their memories become defined or rewritten.

How can it be explained by abondoning Euclidean-like topology of space?
Space on the fundamental level could for example be filled with lots of tiny wormholes that connect distant regions. These wormholes could transfer information between entangled particles.
Similar theory states that entangled particles are connected by some kind of string in higher dimension, which means that actually they are not that far away and communication between them is not superluminal.
 
haael said:
If I understand entropy15's intention well, then he thinks of a theory where distant regions remain in some kind of superposition until they meet, when they adjust themselves to satisfy the Bell theorem.

don't have a fully defined state until they meet. Then, their memories become defined or rewritten.

.
Thats what I had in my mind. But is it not possible that even before they meet, they have a fully defined state. After they meet they readjust themselves so as to satisfy Bells theorem.

After all, our past is stored in our present memories. So the present memory can be changed so that we remember things differently.
 
Last edited:
entropy15 said:
Thats what I had in my mind. But is it not possible that even before they meet, they have a fully defined state. After they meet they readjust themselves so as to satisfy Bells theorem.

After all, our past is stored in our present memories. So the present memory can be changed so that we remember things differently.

you refer to a fundamental principle of symmetry (present at the emision of photons pairs), each photon "knows" it orientation (spin mode).going to that, slowly but going (studying pair by pair)

http://jqi.umd.edu/news/photons-la-mode
http://pra.aps.org/abstract/PRA/v88/i1/e013822

"For instance, to study a pair of entangled photons (created by shooting light into a special crystal where one photon is converted into a pair of secondary, related photons) detection efficiency is all important; and folded into that detection efficiency is a requirement that the arrival of each of the daughter photons be matched to the arrival of the other daughter photon. In addition to this temporal alignment, the spatial alignment of detectors, (each oriented at a specific angle respect to the beamline) must be exquisite. To correct for any type of less-than-perfect alignment, it is necessary to know how many different light modes are arriving at the detector"
"and those that emit pairs of entangled photons---where the quantum relation between the two photons is exactly right"
----
http://arxiv.org/abs/1305.5708.
 
Last edited:
But is it not possible that even before they meet, they have a fully defined state.
Well, anything is possible. I know as much as you. No QM interpretation has been proven, nor even any of it make any experimental predictions.

You ask if the state before meeting is undefined, or is it defined but rewritten. Well, what is the difference? If both these views yield the same experimental results, then they are the same. Besides, we don't have any way to prove the existence of alternative histories, since they are already gone when we seek for them.

Let me state it once again: we don't have any explanation for Bell's theorem or any interpretation for QM that is any better than others. For now, we could speculate of anything.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
311
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 5 ·
Replies
5
Views
472
  • · Replies 2 ·
Replies
2
Views
2K