Localism v Realism: Exploring Bohm's Model & Beyond

  • Thread starter maline
  • Start date
In summary, Bell and Aspect proved you can't have local realism. Bohm set up a model that is realistic but not local. Is there a meaningful model that is local but not realistic? How would it explain the way measurement choices affect distant outcomes?There are a number of interpretations that are local but not realistic in the usual sense. Some people would classify these as "many worlds" while others would say they are a type of "time symmetric/retro-causal/block world". Neither excludes future setup/context from contributing to the present. The answer to the question of "where are the hidden variables": in the future.
  • #1
maline
436
69
Bell & Aspect proved you can't have local realism. Bohm set up a model that is realistic but not local. Is there a meaningful model that is local but not realistic? How would it explain the way measurement choices affect distant outcomes?
 
  • Like
Likes 1 person
Physics news on Phys.org
  • #2
maline said:
Bell & Aspect proved you can't have local realism. Bohm set up a model that is realistic but not local. Is there a meaningful model that is local but not realistic? How would it explain the way measurement choices affect distant outcomes?

There are a number of interpretations that are local but not realistic in the usual sense. Not all people classify these the same as I, but here are a couple:

- Many Worlds

- Time Symmetric/Retro-causal/Block world - these do not not exclude future setup/context from contributing to the present. The answer to the question of "where are the hidden variables": in the future.
 
  • #3
maline said:
Bell & Aspect proved you can't have local realism. Bohm set up a model that is realistic but not local. Is there a meaningful model that is local but not realistic? How would it explain the way measurement choices affect distant outcomes?

The ignorance ensemble interpretation is usually considered local and not realistic - although that would not be my classification. The issue of locality depends on your view of the status of breaking entanglement when entanglement is simply a mathematical device to describe correlations. I personally don't look at it that way and say its both non local and not realistic - but opinions vary.

As you can see, and as Dr Chinese correctly pointed out, not everyone classifys things the same way. Many would classify MW as real because the only thing that exists in it is the universal wavefunction that is as real as they come - in that interpretation that is. So how does MW evade Bell? Its not counterfactual definite - you can't predict the outcome of observations. It's subtle like a lot of this stuff.

The other day I was trying to think of a theory that is real but not couterfactual definite - MW was the only one I could think of and even that required a bit of thought and reading of some literature.

Thanks
Bill
 
Last edited:
  • #4
In many worlds the worlds " can " be infinity worlds but some of them colapst by the viewer , and the numbers of the many world depend on stabilizesion on the viewer , so in bell when you check one side , it stabilize , colapst and afect on the ather side . It come from mulltiply worlds to feu and it some kind of geometry for the particle
 
  • #5
maline said:
Bell & Aspect proved you can't have local realism. Bohm set up a model that is realistic but not local. Is there a meaningful model that is local but not realistic? How would it explain the way measurement choices affect distant outcomes?
See e.g.
http://lanl.arxiv.org/abs/1112.2034 [Int. J. Quantum Inf. 10 (2012) 1241016]
which represents a model in which only observers are real, while the observed objects are not.
 
  • #6
Water nosfim said:
In many worlds the worlds " can " be infinity worlds but some of them colapst by the viewer , and the numbers of the many world depend on stabilizesion on the viewer , so in bell when you check one side , it stabilize , colapst and afect on the ather side . It come from mulltiply worlds to feu and it some kind of geometry for the particle

I don't know what you mean.

But the situation in MW is that after decoherence, which is a purely quantum process, each outcome of an observation in the mixed state that results from decoherence, is interpreted as a new world. Its entirely real because the wavefunction in that interpretation is real, its local because the wavefunction is local, however you can't predict which world you will find yourself in so its not couterfactual definite.

Thanks
Bill
 
  • #7
You find yourself at the world you stabilize in , and it depend on the force you have use to fit in
 
  • #8
bhobba said:
you can't predict which world you will find yourself in

Wouldn't the answer be "definitely both"? What's unpredictable there? and how doer this affect EPR?
 
  • #9
Demystifier said:
See e.g.
http://lanl.arxiv.org/abs/1112.2034 [Int. J. Quantum Inf. 10 (2012) 1241016]
which represents a model in which only observers are real, while the observed objects are not.

Thanks, but according to the abstract this model is still slightly non-local
 
  • #10
maline said:
Wouldn't the answer be "definitely both"? What's unpredictable there? and how doer this affect EPR?

Yea - but how can you say which world you are in - you can't - because you are in all - it fails counterfactual definiteness.

Its subtle and a matter of semantic opinion. Semantics would have to be the silliest thing to argue about, so if you don't agree that's fine by me.

It doesn't affect EPR except as a possible example of an interpretation that is real, local but fails counterfactual definiteness.

Thanks
Bill
 
  • #11
maline said:
Thanks, but according to the abstract this model is still slightly non-local
Yes, but this "small" nonlocality appears only at small distances, not at large distances typical for the EPR experiments.
 

1. What is the difference between localism and realism?

Localism and realism are two contrasting philosophical perspectives that attempt to explain the nature of reality. Localism posits that reality is made up of separate, independent entities that interact with each other locally, while realism argues that there is a deeper, underlying reality that governs the behavior of these entities.

2. What is Bohm's model and how does it relate to localism and realism?

Bohm's model, also known as the pilot-wave theory, is a quantum mechanics interpretation that combines aspects of both localism and realism. It proposes that particles have definite positions and trajectories, but are guided by a hidden wave function that determines their behavior. This model challenges the traditional quantum mechanics view of non-locality and randomness.

3. How does Bohm's model go beyond localism and realism?

Bohm's model goes beyond localism and realism by proposing a new way of understanding the behavior of particles in the quantum world. It suggests that there is a deeper, deterministic reality underlying the seemingly random behavior of particles, while still maintaining the idea of locality and individuality of particles.

4. What are some criticisms of Bohm's model?

Some criticisms of Bohm's model include its dependence on a hidden variable and the idea of non-locality. Critics argue that the model is not testable and goes against the principles of relativity. Additionally, some argue that the model does not fully explain all phenomena observed in the quantum world.

5. How has the debate between localism and realism evolved over time?

The debate between localism and realism has evolved over time as new scientific discoveries and theories have emerged. Initially, realism was the dominant perspective, but the development of quantum mechanics and its counter-intuitive principles challenged this view. Bohm's model provided a new perspective, but it is still a topic of debate and further research is ongoing to better understand the nature of reality.

Similar threads

I Bell's theorem claimed to be refuted - paper published by EPL
    • Quantum Physics
2
Replies
50
Views
4K
I Big Bell Test Collaboration: Challenging Local Realism with Human Choices
    • Quantum Physics
Replies
6
Views
2K
Mathematical formulation of local non-realism
    • Quantum Physics
Replies
5
Views
2K
A Loophole-free test of local realism via Hardy's violation
    • Quantum Interpretations and Foundations
2
Replies
37
Views
1K
B Quantum entanglement and hidden variables
    • Quantum Physics
Replies
7
Views
1K
I Assuming nonlocal realism: What message would signal convey?
    • Quantum Physics
Replies
30
Views
3K
I The notion of locality in (Quantum) Physics should be clearly defined
    • Quantum Interpretations and Foundations
6
Replies
175
Views
6K
A Bell Test Violates Local Realism w/ Loophole-Free Electron Spins 1.3km Apart
    • Quantum Physics
2
Replies
63
Views
7K
I Difference between "realistic" and "predetermined"
    • Quantum Physics
Replies
2
Views
1K
I Cosmic Bell Test: 600 yr Old "Freedom of Choice" Loophole
    • Quantum Physics
Replies
8
Views
2K

Hot Threads

Recent Insights

Back
Top