Math: classical to quantum locality

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Discussion Overview

The discussion revolves around the concepts of quantum locality and nonlocality, particularly in relation to the Planck scale and its implications for Einstein's spacetime theories. Participants explore the nature of quantum phenomena, the relationship between object size and wavelength, and the implications of quantum mechanics on locality.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants propose that at the Planck scale, all points in space and time are local, suggesting that nonlocality does not exist at this scale.
  • Others argue that if nonlocality exists, it does not disappear at the Planck scale and that the Planck scale does not explain General or Special Relativity.
  • There is a claim that objects experience quantum phenomena because their size is smaller than their wavelength, which some participants challenge, stating that this is a misconception.
  • One participant mentions that quantum phenomena can occur in macroscopic objects, countering the idea that quantum mechanics is only relevant at microscopic scales.
  • Another participant highlights that the de Broglie equation relates wavelength to momentum, not size, and emphasizes that decoherence, rather than wavelength, explains why quantum phenomena are not observed at macroscopic levels.
  • Some participants discuss the implications of Quantum Field Theory and its locality, referencing the Cluster Decomposition property and Bell's inequalities.

Areas of Agreement / Disagreement

Participants express multiple competing views on the relationship between size, wavelength, and quantum phenomena, as well as the nature of locality and nonlocality. The discussion remains unresolved with no consensus on these points.

Contextual Notes

Participants note that the understanding of locality and nonlocality is complex and may depend on various interpretations of quantum mechanics and relativity. The discussion includes references to specific theories and equations, but these are not universally accepted or agreed upon.

awcrowe
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Does anybody know if there is work being done on quantum locality vs nonlocality.

Specifically, approaching the Planck scales there is no nonlocality. That is all points in space and time are local. This would also provide an explanation for Einstein Minkowsky's space time.

Any material / talks would be appreciated.
 
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awcrowe said:
Any material / talks would be appreciated.
Talks? Here's a forum search:
https://www.physicsforums.com/search/91620209/?q=nonlocality&o=relevance
https://www.physicsforums.com/search/91620242/?q=nonlocality%2C+locality&o=relevance

Not sure how many actual valid references there will be included, but there is definitely enough to read.
 
awcrowe said:
Specifically, approaching the Planck scales there is no nonlocality. That is all points in space and time are local. This would also provide an explanation for Einstein Minkowsky's space time.

A note: If there is nonlocality, it does not disappear at the Planck scale. Also: the Planck scale does not "explain" General or Special Relativity.
 
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fresh_42 said:
Talks? Here's a forum search:
https://www.physicsforums.com/search/91620209/?q=nonlocality&o=relevance
https://www.physicsforums.com/search/91620242/?q=nonlocality%2C+locality&o=relevance

Not sure how many actual valid references there will be included, but there is definitely enough to read.

Thanks
 
DrChinese said:
A note: If there is nonlocality, it does not disappear at the Planck scale. Also: the Planck scale does not "explain" General or Special Relativity.

Objects experience quantum phenomena because the object's size is smaller than its wave length. This same rule may be part of how locality works in space.
 
awcrowe said:
Objects experience quantum phenomena because the object's size is smaller than its wave length. This same rule may be part of how locality works in space.

Nope. Physical size has nothing to do with it. At least not directly.
There are plenty of demonstrations of macroscopic objects exhibiting "quantumness"
The idea that QM is somehow only relevant at the microscopic (or even subatomic) scale is a common misconception.
 
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awcrowe said:
1. Objects experience quantum phenomena because the object's size is smaller than its wave length.

2. This same rule may be part of how locality works in space.

1. As f95toli already indicated, this is not correct - at many levels. And none of these have anything to do with the Planck scale.

2. Locality is fairly well understood, and described in various ways by relativity. It is nonlocality that is a bit trickier, although the quantum mechanical descriptions are well tested.
 
DrChinese said:
A note: If there is nonlocality, it does not disappear at the Planck scale. Also: the Planck scale does not "explain" General or Special Relativity.

Objects experience quantum phenomena because the object's size is smaller than its wave length. This same rule may be part of how locality works in space.
 
Sorry you are just wrong the de-Broglie equation shows the relationship between size of an object and wavelength which is related to whether it experiences quantum phenomena.

We do not experiece quantum phenomena at the macroscopic level because of the wave length. How nonlocality happens at the microscopic level may have more to do with the effects of particles on and the nature of space time than the particles themselves.
 
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awcrowe said:
Objects experience quantum phenomena because the object's size is smaller than its wave length. This same rule may be part of how locality works in space.

As already explained, this is wrong. Quantum objects don't even possesses something you might call "size" at all times. What is the size of a photon? What is the size of an electron? What is the size of a molecule? Their quantum properties do not cease (nor begin) to exist at scales related to their wavelength.
 
  • #11
awcrowe said:
We do not experiece [sic] quantum phenomena at the macroscopic level because of the wave length. How nonlocality happens at the microscopic level may have more to do with the effects of particles on and the nature of space time than the particles themselves.

As a simple example of how wrong this is, consider the quantum phenomena called entanglement. Quantum nonlocality has been demonstrated over very large distances (many miles). Experiment demonstrates it has nothing to do with effect of the particles on space time, and certainly is not limited by wavelength.

You should not make up ideas and post them here. Cite a source to back up your speculations. Else expect a report to the moderators. If you have a question, ask it. You made a reference in the OP to non-locality, and there is substantial work being done to describe and demonstrate quantum nonlocality. What would you like to know?
 
  • #12
awcrowe said:
Sorry you are just wrong the de-Broglie equation shows the relationship between size of an object and wavelength which is related to whether it experiences quantum phenomena.
The de Broglie equation shows the relationship between the wavelength and the momentum, not the size, of a particle. "Size" doesn't appear anywhere in it.
We do not experience quantum phenomena at the macroscopic level because of the wave length.
Decoherence is the issue here, not the wavelength.
 
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  • #13
As far as locality goes remember our most fundamental theory is Quantum Field Theory which being relativistic has locality. It doesn't resolve anything about the Bell inequalities etc but it is always wise to remember the so called Cluster Decomposition property of Weinberg:
https://www.physicsforums.com/threads/cluster-decomposition-in-qft.547574/

I will let you think about it's implications, but personally I am a bit of a maverick in that I exclude correlations from discussions on locality. Doing that renders much of the 'confusion' surrounding FTL, Bell etc moot. It doesn't disprove it or anything like that - but to me everything is much simpler without it.

And of course one should always read Bell's original paper:
https://hal.archives-ouvertes.fr/jpa-00220688/document

Thanks
Bill
 
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