Other terms for indeterministic hidden variables

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Discussion Overview

The discussion revolves around the terminology and conceptual framework for indeterministic hidden variables that do not adhere to counterfactual definiteness, particularly in the context of quantum mechanics. Participants explore various terms and theories related to hidden variables, contextuality, and their implications for quantum processes.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that the term "hidden variable" should be reserved for deterministic counterfactual definite variables and questions what to call indeterministic non-counterfactual definite variables.
  • Another participant expresses skepticism about the need for a specific term for indeterministic hidden variables, suggesting that the distinction may not be significant enough to warrant it.
  • Feynman's sum over histories is proposed as a novel type of hidden variable theory, which is non-deterministic and involves all possible paths.
  • Primary state diffusion is mentioned as an interesting non-equivalent theory to quantum mechanics that can bypass certain no-go theorems.
  • Nelson Stochastics is also referenced as a relevant theory in this context.
  • Participants discuss whether non-local hidden variables would only affect entangled systems or if they would also influence everyday quantum dynamics in decohered states.
  • There is a suggestion that a successful hidden variable theory would predict the same results as quantum mechanics and could apply broadly.
  • Concerns are raised about the implications of hidden variables for quantum computing, particularly regarding information encoding and whether hidden variable theories would necessitate changes in quantum computing concepts.
  • One participant argues that hidden variable theories are designed to be indistinguishable from standard quantum mechanics, implying that they would not allow for additional information encoding in quantum systems.
  • Counterfactual definiteness is discussed as a Newtonian concept, with some participants advocating for a focus on contextuality and non-realism instead.

Areas of Agreement / Disagreement

Participants express a range of views on the terminology and implications of indeterministic hidden variables, with no clear consensus on the appropriate terms or the significance of the distinctions being made. The discussion remains unresolved regarding the classification and implications of these theories.

Contextual Notes

Participants highlight the complexity of defining terms related to hidden variables and contextuality, as well as the potential limitations of existing theories in addressing these concepts. There is an acknowledgment of the unresolved nature of certain mathematical and theoretical aspects.

Who May Find This Useful

This discussion may be of interest to those exploring the foundations of quantum mechanics, hidden variable theories, and the implications of contextuality in quantum systems.

gva
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If there were nonlocal hidden variables that are indeterministic and doesn't obey counterfactual definiteness. What terms should they be called. I think hidden variable should only be reserved for deterministic counterfactual definite.

What then should we refer to indeterministic non-counterfactual definiteness. You may state contextuality? But contextuality is not hidden variables. I'm referring to actual processes in say the quantum vacuum that can produce stochastic randomness in the wave function. What term should we refer to it? Objective collapse? but it's not about collapse and not objective.

Please suggest a term.
 
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I am not aware of any such term being in general use, and expect that that is because the classification between deterministic and non-deterministic hidden variable theories is not interesting enough to require it.
 
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Nugatory said:
I am not aware of any such term being in general use, and expect that that is because the classification between deterministic and non-deterministic hidden variable theories is not interesting enough to require it.

There are official non-deterministic hidden variable theories? any references about this or examples?
 
gva said:
There are official non-deterministic hidden variable theories? any references about this or examples?

Well Feynman's sum over history approach is really a hidden variable theory - but of a very novel type. The path is the hidden variable and most definitely is not deterministic - it takes all paths.

That said, while novel, it's really not that interesting in discussions about hidden variables since such 'weird' things are not what attract people to such theories because they want a more common sense view of the world.

Another example, and more interesting as an actual theory, is primary state diffusion:
http://arxiv.org/pdf/quant-ph/9508021.pdf

Its quite interesting because its not actually equivalent to QM - in that way it can bypass no go theorems like Bell and Kochen-Sprecker.

We also have Nelson Stochastics
http://philsci-archive.pitt.edu/8853/1/Nelson-revised.pdf:

Thanks
Bill
 
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bhobba said:
Well Feynman's sum over history approach is really a hidden variable theory - but of a very novel type. The path is the hidden variable and most definitely is not deterministic - it takes all paths.

That said, while novel, it's really not that interesting in discussions about hidden variables since such 'weird' things are not what attract people to such theories because they want a more common sense view of the world.

Another example, and more interesting as an actual theory, is primary state diffusion:
http://arxiv.org/pdf/quant-ph/9508021.pdf

Its quite interesting because its not actually equivalent to QM - in that way it can bypass no go theorems like Bell and Kochen-Sprecker.

We also have Nelson Stochastics
http://philsci-archive.pitt.edu/8853/1/Nelson-revised.pdf:

Thanks
Bill

If there were really non-local hidden variables.. does it only affect system in an entanglement state? Or does it also affect everyday quantum dynamics in a decohered state?
 
gva said:
If there were really non-local hidden variables.. does it only affect system in an entanglement state? Or does it also affect everyday quantum dynamics in a decohered state?
A hidden variable theory would use the hidden variables to predict the same results as quantum mechanics, so would apply everywhere that QM does (and perhaps even more broadly).

A successful hidden variable theory would be to quantum mechanics as classical mechanics is to thermodynamics.
 
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Nugatory said:
A hidden variable theory would use the hidden variables to predict the same results as quantum mechanics, so would apply everywhere that QM does (and perhaps even more broadly).

A successful hidden variable theory would be to quantum mechanics as classical mechanics is to thermodynamics.

In quantum computing, the electron spin up and down can be used to encode 0 and 1. If there was hidden variable, can one encode more information in the quantum system. Or in other words, would there be changes in quantum computing concepts if there were (nonlocal) hidden variable?
 
gva said:
In quantum computing, the electron spin up and down can be used to encode 0 and 1. If there was hidden variable, can one encode more information in the quantum system. Or in other words, would there be changes in quantum computing concepts if there were (nonlocal) hidden variable?
This is like asking whether if we discovered a new theory of aerodynamics, would there be changes in aircraft engineering concepts that allowed us to build planes that flew higher and faster. The question makes no sense unless and until we have a particular candidate theory in mind.

However, any acceptable hidden variable theory must agree with QM everywhere that QM has been shown to work. As QM already does an excellent job at describing the behavior of electrons, there is little chance that a hidden variable theory that explains why QM works will change the way we manipulate electrons.

I've already used the analogy with thermodynamics once, and it applies here as well. We were applying thermodynamics long before we discovered the hidden variable explanation for why it works so well. That discovery didn't force a rethinking of how we apply thermodynamics.
 
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gva said:
If there was hidden variable, can one encode more information in the quantum system. Or in other words, would there be changes in quantum computing concepts if there were (nonlocal) hidden variable?

Of course not.

Hidden variable theories (with a couple of exceptions such as Primary State Diffusion) are deliberately cooked up to be indistinguishable from standard QM. It is doubtful those few exceptions would allow that.

Thanks
Bill
 
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gva said:
If there were nonlocal hidden variables that are indeterministic and doesn't obey counterfactual definiteness. What terms should they be called. I think hidden variable should only be reserved for deterministic counterfactual definite.
Any hidden variable theory implies counterfactual definiteness, at least if the theory is so detailed that it can be written as a computer program.

Assume for the sake of argument that the theory is implemented as a computer simulation. We simulate a run with Alice's detector setting equal to A1, and get a result. Then we run the program again with setting equal to A2, keeping everything else about the program unchanged, including the values of any random variables from the first run. This will always be possible, and is equivalent to "counterfactual definiteness".
 
  • #11
Counterfactual definiteness is very Newtonian.. and if this is related to hidden variable (which it is) and realism.. then those of us who prefer contextuality should avoid it all altogether. So let me now focus on non-realism or contextuality. What do you call that extra variable inside contextual QM where it can determine the born rule?
 

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