How valid is the indivisible interpretation of quantum mechanics?

[DarkloidNeos]

TL;DR

As on the tin

I was reading up on the theory and apparently it's saying stuff that is in direct opposition with current views like how there is no wave function, but that quantum processes occur by randomness? I'm not sure how valid it might be but all I know is that it's a massive departure from the usual stuff.

 

[PeterDonis]

Moderator's note: Thread moved to the QM interpretations subforum.

 

[PeterDonis]

I was reading up on the theory

Where? Please give a specific reference. "The indivisible interpretation" is not any recognized interpretation that I've heard of.

 

[DarkloidNeos]

Where? Please give a specific reference. "The indivisible interpretation" is not any recognized interpretation that I've heard of.

https://ncatlab.org/nlab/show/indivisible+stochastic+process+interpretation+of+quantum+mechanics

 

[PeterDonis]

https://ncatlab.org/nlab/show/indivisible+stochastic+process+interpretation+of+quantum+mechanics

Ah, ok. This references several papers by Jacob Barandes, whose work has been discussed in previous PF threads. This one is probably the best place to start:

P

Undergrad Thread 'A new realistic stochastic interpretation of Quantum Mechanics'

Mar 4, 2024

These papers claim to present a realistic stochastic interpretation of quantum mechanics that obeys a stochastic form of local causality. (A lecture I recently attended mentioned these papers). It also claims the Born rule as a natural consequence rather than an assumption. This appears to me to be a genuinely new interpretation. I have not delved into the papers in detail, but figured some people here may be interested.

https://arxiv.org/abs/2302.10778
https://arxiv.org/abs/2309.03085
https://arxiv.org/abs/2402.16935

• PAllen
• Causality Local Stochastic
• Replies: 710
• Forum: Quantum Interpretations and Foundations

• 

As far as how "valid" this interpretation is, that's a meaningless question for any QM interpretation. All of them make the same predictions for experimental results, so there's no way to test them against each other by experiment. So it comes down to personal preferences about what kind of story to tell about what is "really happening" in quantum experiments.

 

[gentzen]

If you want to read something recent from Jacob Barandes, I would rather go with

https://arxiv.org/abs/2602.09397 "historical debates over the physical reality of the wave functions", J.Barandes

Barandes certainly has his reasons why he proposed his "indivisible stochastic process" interpretation: A wavefunction in configuration space is not a thing we would normally call "real". So he goes with a stochastic trajectory in a state space instead. It is consistent and doesn't contradict the math of QM. However, those trajectories lack "causal power". This is a phenomenon I first read about in "Do we really understand quantum mechanics?" by Franck Laloë when he described modal interpretations and their issues.

In contrast, trajectories in Bohmian mechanics don't lack "causal power" in the same way. This may seem surprising first, because they just seem to go where the wavefunction directs them, without affecting the wavefunction itself.

 

[pines-demon]

As interpretations are mostly "what feels right" philosophically, I can argue that it does not help much in understanding the concept of entanglement. It "feels as weird" as Bohmian mechanics or superdeterminism in that regard.

Mathematically it is much interesting as it provides a duality between an explored field of knowledge (quantum mechanics) and the completely unexplored world of indivisible stochastic mechanics (if this field is helpful for anything is yet to be answered).

 

[Paul Colby]

So, dressing the same physics up in a different mathematical framework definitely can have value. However, how is this mathematical formalism more realistic than what one started with? QM things still do QM things.

 

[pines-demon]

However, how is this mathematical formalism more realistic than what one started with? QM things still do QM things.

Define realistic.

 

[Paul Colby]

Define realistic.

Clearly, I can’t. Which is also my point. Neither has anyone else. I’m also not the one employing such a term.

 

[pines-demon]

Clearly, I can’t. Which is also my point. Neither has anyone else. I’m also not the one employing such a term.

Any definition will do. All interpretations are physically valid (in the sense that predict the same phenomena). So at this point one just needs to indicate what kind of criteria they want more and we can argue which interpretation approximates that criteria better.

 

[gentzen]

Any definition will do.

Here is Barandes' own definition from the abstract:

This paper provides a detailed historical account of early debates over wave-function realism, the modern term for the view that the wave function of quantum theory is physically real. As this paper will show, the idea of physical waves associated with particles had its roots in work by Einstein and de Broglie, who both originally thought of these waves as propagating in three-dimensional physical space. [...] The present work will argue that this move from three-dimensional physical space to a many-dimensional configuration space was a key reason why the founders of quantum theory uniformly abandoned the physical reality of the wave function.

 

[Sambuco]

Here is Barandes' own definition from the abstract:

Although it is a "problematic" term, I think the definition of realism in quantum foundations is generally linked to the idea that systems possess properties outside of measurements (just as in the EPR paper), whereas Barandes' quote refers specifically to "wave function realism", more in line with the usual $\psi$-ontic vs. $\psi$-epistemic debate.

Lucas.

 

[pines-demon]

Although it is a "problematic" term, I think the definition of realism in quantum foundations is generally linked to the idea that systems possess properties outside of measurements (just as in the EPR paper), whereas Barandes' quote refers specifically to "wave function realism", more in line with the usual $\psi$-ontic vs. $\psi$-epistemic debate.

Here is Barandes' own definition from the abstract:

To be fair I was asking for definition of "realistic" which I would say is more about the interpretation being pragmatic than adhering to whatever "realism" means.

 

[Paul Colby]

Any definition will do.

I agree. In philosophy any statement X may be argued as well as any statement not X with no acceptable means of determining which, if any[1], is to be preferred.

[1] don’t leave out any middles.

 

[sbrothy]

I'd almost love if someone was able to stoop to my level and explain to me why the The Montevideo Interpretation of QM doesn't at least a point to a solution to the measurement problem:

The Montevideo Interpretation: How the inclusion of a Quantum Gravitational Notion of Time Solves the Measurement Problem

But especially why the concept of real clocks doesn't say something meaningful about decoherence:

Assessing the Montevideo Interpretation of Quantum Mechanics

You'd just be wasting your time so don't try. It's once again because I don't really understand the math and because I tend to gloss over things too fast. And worst of all, think physics concepts have intuitive solutions.

I wish I understood though. Ah well.

It's old papers and they don't seem to have attracted any real interest. I probably should take that as an explanation if nothing else.

 

[gentzen]

I think the definition of realism in quantum foundations is generally linked to the idea that systems possess properties outside of measurements (just as in the EPR paper)

Yes, in "quantum foundations". That is why I said "normally":

A wavefunction in configuration space is not a thing we would normally call "real".

This is about understanding Barandes' motivations, not necessarily about agreeing with him.

 

[gentzen]

It's old papers and they don't seem to have attracted any real interest. I probably should take that as an explanation if nothing else.

What I understood from
https://physics.stackexchange.com/q...tation-of-quantum-mechanics-do-what-it-claims
is

that the Montevideo interpretation is not really an "interpretation" at all, but new physics that makes new and different testable predictions

 

[pines-demon]

why the The Montevideo Interpretation of QM

We should have more interpretations named after cities, having just two is unfortunate.

 

[Morbert]

We should have more interpretations named after cities, having just two is unfortunate.

There's the ETH interpretation of QM. ETH stands for events, trees, and histories, but I suspect it is a nod to ETH Zurich.

 

[sbrothy]

What I understood from
https://physics.stackexchange.com/q...tation-of-quantum-mechanics-do-what-it-claims
is

Yeah, I may have underestimated it. But isn't it a moot point reaching the limit of clocks? Like reaching absolute zero. I may to need some more papers on the topic; and retain better.

 

[sbrothy]

What I understood from
https://physics.stackexchange.com/q...tation-of-quantum-mechanics-do-what-it-claims
is

This is an extremely interesting discussion. I wonder how I overlooked it. I realize my math-limits will be a problem understanding this, especially in light of this:

[...] modified Schroedinger equation [...]

I realize it's still time-related but that's kinda the limit of my understanding (and reading).

Still, fascinating.

 

[PeterDonis]

I'd almost love if someone was able to stoop to my level and explain to me why the The Montevideo Interpretation of QM doesn't at least a point to a solution to the measurement problem:

Pretty much every interpretation says it at least points to a solution of the measurement problem, and within the context of each interpretation, what it points to at least appears to make sense. So nobody will be able to give you what you're asking for here. The issue with all QM interpretations is not that they don't offer solutions to conceptual problems with QM; the issue is that we have no way of testing any of them by experiment, because they all make the same predictions for experimental results.

 

[sbrothy]

Pretty much every interpretation says it at least points to a solution of the measurement problem, and within the context of each interpretation, what it points to at least appears to make sense. So nobody will be able to give you what you're asking for here. The issue with all QM interpretations is not that they don't offer solutions to conceptual problems with QM; the issue is that we have no way of testing any of them by experiment, because they all make the same predictions for experimental results.

Yeah, and I understand that asking "Why does nature behave like this and not like that?", ("Shut up and calculate!") de facto doesn't make a whole lot of sense. I'm just still under the perhaps naive belief that philosphy of physics might at least uncover new avenues for both theory and experiments!

 

[martinbn]

We should have more interpretations named after cities, having just two is unfortunate.

Doesn't this one make it three?

 

[iste]

there is also the vaxjo interpretation of quantum mechanics - a swedish city

 

[pines-demon]

there is also the vaxjo interpretation of quantum mechanics - a swedish city

I'm happier now.

Doesn't this one make it three?

What is the other one? Copenhagen, Montevideo, (Växjö,) and?

 

[gentzen]

What is the other one? Copenhagen, Montevideo, (Växjö,) and?

ETH, Ithaca, ...?

 

[physika]

a plethora...

 

[DarkloidNeos]

If you want to read something recent from Jacob Barandes, I would rather go with


Barandes certainly has his reasons why he proposed his "indivisible stochastic process" interpretation: A wavefunction in configuration space is not a thing we would normally call "real". So he goes with a stochastic trajectory in a state space instead. It is consistent and doesn't contradict the math of QM. However, those trajectories lack "causal power". This is a phenomenon I first read about in "Do we really understand quantum mechanics?" by Franck Laloë when he described modal interpretations and their issues.

In contrast, trajectories in Bohmian mechanics don't lack "causal power" in the same way. This may seem surprising first, because they just seem to go where the wavefunction directs them, without affecting the wavefunction itself.

From what I read the lack of causality is a feature and not a bug since it's supposed to break it and suggest that things happen randomly. Though I don't know how accurate that is.