I A new realistic stochastic interpretation of Quantum Mechanics

[iste]

The conceptual idea in several your links are indeed just in line with what I mention!

I'm glad they resonated with you!

 

[Fra]

Is "sampling" a mathematical or a physical concept? If it refers to "measurement", does the new formulation shed any light on which interactions count as measurements?

This is a good question, and while it is a mathematical concept in the abstractions, just like there are different "interpretations" of probability, that must somehow be reflected in physical view of "sampling".

In a pure minimal statistical interpretation, like the typical one for QM, the "sampling" is defined from the perspective of a measurement devices that collectes statistics by repeating experiments, defined by preparation procedures.

But such as "interpretation" of sampling makes not sense in a gaming perspective or agent interpretation, for several reasons.

I think interactions and measurements must be unified, and the difference between a measurement and an interaction is a matter of perspective. Typically the inside perspective of the "observer/agent" is measurements and actions, the perspective of a third observer observing the "first agent measuring a system" will typically describe it not as a measurement, but as an interaction.

The challenge is to unifify the two views in the sense to revealing the relation between the dual views of measurement and interactions. And this is where the conceptual view on "quantum interactions" as disagreement between information sources/agents becomes explicit. Ie the "explanation of interactions" is likely simple, in the dual view, then you can work there, and then transform back! Simple trick that is a generic one also in adS/CFT or more general dualities, gravity etc. I think they keys in barandes paper is steps in the direction, but there is alot more do be clarified.

/Fredrik

 

[WernerQH]

if we can formulate quantum mechanics successfully in terms of particles being "classical-looking" then this seems like the most parsimonious way to interpret quantum mechanics because that is what we expected reality to look like before all the quantum confusion turned up.

Bohmian philosophy. My expectations are quite different. From what we have learned in the last century it seems evident to me that quantum theory is not about "particles". The awkwardness of quanta is rooted in our desire to describe the world around us as composed of objects. As it turned out these quantum objects have properties that are blurred or even undefined (but somehow "entangled") and become manifest only upon "measurement", something the theory leaves undefined. It is ironic that our most successful tool for describing the microworld, Feynman diagrams, pictures it in terms of particles. But, as some members here on PF never tire to emphasize, one should not think of the lines in Feynman diagrams as representing real particles. It is a strange concept that these "particles" are identical. There is no fact of the matter that "this" photon interacted with "that" electron. The Feynman rules tell us to connect the vertices in all possible ways, multiply the propagators, and add up the resulting expressions. A stochastic interpretation of quantum theory should treat the interaction events as real, and not the lines connecting them. I see QFT as a machinery for calculating the correlations between events (points) in spacetime, what mathematicians would call a point process or point field. I think it's a hopeless task of attributing (hidden) stochastic variables to electrons and photons to produce a theory equivalent to QED, but still having a "classical" flavor.

it is very hard not to interpret this just as particles always being in one definite place or configuration at a time and moving around under some random influence. Its only natural to interpret the outcomes of stochastic processes or random variables as physical events - e.g. the outcome of a dice roll is a physical event.

I find it hard to believe in particles, and I have a much more primitive idea of physical event. For example, the emission of a photon. Actually, the emission of a photon does not occur in an instant -- the event is itself composed of two elementary (more "primitive") events separated in time. This leaves enough room for non-Markovian indivisibility.

 

[PeterDonis]

I find it hard to believe in particles, and I have a much more primitive idea of physical event. For example, the emission of a photon.

You're contradicting yourself. A "photon" is a particle, and "emission of a photon" is a particle process.

Actually, the emission of a photon does not occur in an instant -- the event is itself composed of two elementary (more "primitive") events separated in time.

Where are you getting this from? Do you have a reference?

In quantum field theory, "emission of a photon" is a mathematical artifact and has no physical meaning.

 

[iste]

Bohmian philosophy. My expectations are quite different. From what we have learned in the last century it seems evident to me that quantum theory is not about "particles".

That's fair enough if thats your inclination. I can only say that Barandes' formulation would actually agree with the notion that quantum mechanics isn't strictly because the objects of quantum objects are translated only from the stochastic random variables and probability spaces so these are at least implicitly are about the long-run statistics of particles, not individual particles and physical events themselves. It's no contradiction that the quantum objects can then have "properties that are blurred or even undefined", because statistics is about uncertainty. Barandes also says the formulation is general enough to be applicable to quantum field theory. So I don't think there are necessarily any contradictions here either when broadening or deepening the kinds of objects or ontologies being talked about.

 

[Fra]

Bohmian philosophy. My expectations are quite different. From what we have learned in the last century it seems evident to me that quantum theory is not about "particles". The awkwardness of quanta is rooted in our desire to describe the world around us as composed of objects. As it turned out these quantum objects have properties that are blurred or even undefined (but somehow "entangled") and become manifest only upon "measurement", something the theory leaves undefined.

I don't agree the essence of the ideas are traditional Bohmian philosophy. I do however see a conceptual relation to the non-traditional "solipsist hidden variables", even thought that is only conceptually, the actual theory is still missing. But as I see it, agent-defined "solipsist" hidden variables, would be expected to violate the non-markovian divisiblity.

Why? IMO, it has not so much to do with what a particle "is", wether it's a point like bullet, a blob or entangled parts, the essential part which i think is at the heart of that assumption in bells theorem is how these system "particles, or blob or whatever" are INTERACTING.

I think the most problematic preconception from classical physics, is not that we want to imagine that something is definite, but how to describe the dynamics and interactions of interacting parts. How can we possible "understand" interactions that emerge at low energies, from the high energy picture? Without running into extreme fine tuning?

There are two commen ways to model, system dynamics (basically differential equations), and by nature they tend to work best on markovian systems, as the "differential change" typically depend on the current state only. That's how it works. This is why such "models" have great difficulty to model emergent phenomena, and thus you just get "effective models". This is partly I think emphasies by CHOOSING to focus on "system dynamics". That itself puts form-constraints on the theory.

Here ABM (agent based models) have sometimes and edge to model non-markovian phenomena, with emergence. As this more naturally can encode the causal mechanisms of the emergence.

This is now new, but it's not as common in particle physics simply because we do not have an a theory of interactions in and inside perspective. This is why examples are more abundant in comlpex systems such as social and human interactions. I think we can learn from it, and gain insight into modelling emergence also in physics.

To agent based models and system dyamics are complementary. Systems dynamics typically always yield at static state space and timeless law (which is also what Smoling object to in evolution of law, this is related to the same topic imo)

Random paper relating to this just as generic reference (nothing of this is new, but i just suggest this have the same abstractions as exists in physics, and is part of the interpretations)

Agent-based modeling: Methods and techniques for simulating human systems​

"One may want to use ABM when there is potential for emergent phenomena, i.e., when:

• Individual behavior is nonlinear and can be characterized by thresholds, if-then rules, or nonlinear coupling. Describing discontinuity in individual behavior is difficult with differential equations.

• Individual behavior exhibits memory(*), path-dependence, and hysteresis, non-markovian behavior, or temporal correlations, including learning and adaptation."

- https://www.pnas.org/doi/10.1073/pnas.082080899

These things are exactly why the key assumption in Bells theorem is not applicable imo, and this is also the key in barandes ideas. (the ontop of this there are lots more details you could argue about, but it gets opaque to discuss every thing at every level at once)

So I suggest the "stochastic modelling" should be applied NOT to system dynamics but to corresponding agent based model. That might work, but we still have to see the full theory.

Edit: (*) Before someone jumps into conclusions that particles must have brains, the idea here would be that the "memory" is not encoded in the STATE, but in the stateSPACE - which is presumable EMERGENT. So no human observers are required here. That is the persistent misinterpretation that tends to never die. And in terms of System dynamics, this is then "solved" by increasing the dimenstionality of the dependent variables, making it "higher order" etc. But all that does, is increasing complexity to the point where suddently you have a terrible fine tuning problem, and you get only an "effective theory" still, without much explanatory value. Another association to "memory" is IMO weakly related to underlying ideas in this paper from Smolin https://arxiv.org/abs/1205.3707, what he calls "principle of precedence".

/Fredrik

 

[WernerQH]

It's no contradiction that the quantum objects can then have "properties that are blurred or even undefined", because statistics is about uncertainty.

Saying that quantum (field) theory is about statistics is not completely wrong. But it leaves many questions unanswered.

 

[iste]

that quantum mechanics isn't strictly because the objects of quantum objects are translated only from the stochastic

Uhh just noticed this mistake. Should read:

Isn't strictly about particles because the objects of quantum mechanics are translated only from the stochastic

Saying that quantum (field) theory is about statistics is not completely wrong. But it leaves many questions unanswered.

Yes, fair!

 

[WernerQH]

Photons do not exist -- emission of radiation as a mathematical artifact:

In quantum field theory, "emission of a photon" is a mathematical artifact and has no physical meaning.

Obviously light quanta are still controversial.

 

[collinsmark]

Photons do not exist -- emission of radiation as a mathematical artifact:

In quantum field theory, "emission of a photon" is a mathematical artifact and has no physical meaning.

Obviously light quanta are still controversial.

Actually, I never really thought about this until now. But I think the key word here is "emission." I don't think anybody was debating the existence of photons.

Sure, it's easy enough to measure the reception of a photon (well, easier perhaps), but how do you measure/observe the emission of a photon without inferring it via mathematical artifacts?

 

[WernerQH]

Sure, it's easy enough to measure the reception of a photon (well, easier perhaps), but how do you measure/observe the emission of a photon without inferring it via mathematical artifacts?

Yes, photon is a theoretical concept. But in quantum field theory emission is just the time reverse of absorption. And the transfer of energy from an atom to the radiation field and vice versa is surely something physical.

 

[PeterDonis]

Photons do not exist -- emission of radiation as a mathematical artifact:

That's not what I said. Emission of radiation is a physically measurable process. But emission of radiation is not the same as emission of a photon.

Obviously light quanta are still controversial.

Depends on what you mean by "light quanta". You need to be a lot more precise in your usage of terminology.

 

[WernerQH]

Emission of radiation is a physically measurable process. But emission of radiation is not the same as emission of a photon.

Isn't it possible to count individual photons in the laboratory? Aren't they some sort of radiation?

You need to be a lot more precise in your usage of terminology.

I thought I had used the term "photon" as the vast majority of physicists use it. On the other hand I have repeatedly failed to make sense of the distinctions that you deemed necessary concerning "photons" in several other posts of yours. Perhaps it would help if you clarified in an insight article what you perceive as a wide-spread misunderstanding. I'd be happy to use the correct terminology if only I understood what bothers you about how other physicists use the word photon. If you have a deeper understanding, please share it.

 

[PeterDonis]

Isn't it possible to count individual photons in the laboratory?

It is possible to run experiments in which there are discrete detection events that some people describe as "detection of photons". But in most of those experiments, the state of the electromagnetic field is not an eigenstate of photon number and is not usefully described as "photons". The most common such state is a coherent state, which is an eigenstate of the annihilation operator--which means, heuristically, that "detecting a photon" when the field is in this state does not change the field state.

Aren't they some sort of radiation?

Electromagnetic radiation certainly exists, but is not usefully described as "made of photons" except in a very vague and heuristic sense that is seldom useful for actually making predictions.

I thought I had used the term "photon" as the vast majority of physicists use it.

In informal contexts, i.e., where nobody is actually trying to make predictions or teach others how to make predictions, or talk about the foundations of the theories we use to make predictions, physicists do often use the term "photon" loosely. But this is not such a context.

If you have a deeper understanding, please share it.

I have already done so in plenty of those previous threads you refer to. Your suggestion of writing an Insights article, though, is a good one and I will try to do that.

 

[WernerQH]

It is possible to run experiments in which there are discrete detection events that some people describe as "detection of photons". But in most of those experiments, the state of the electromagnetic field is not an eigenstate of photon number and is not usefully described as "photons".

Gamma-ray astronomers have no qualms expressing their results as photon fluxes. And it's surely difficult for them to "prepare" the radiation field in a photon number eigenstate. It's a mystery why you deny the usefulness of reporting their results as photon fluxes. It's the detector counts what they directly measure.

The most common such state is a coherent state, which is an eigenstate of the annihilation operator--which means, heuristically, that "detecting a photon" when the field is in this state does not change the field state.

A coherent state is a theoretician's plaything, because it most closely resembles a classical field. The most common state encountered in nature is a thermal state, which has a vast spread over the energies and nothing of the infinite phase stability of a coherent state. And of course detecting a photon changes the field state, decreasing its energy by $h\nu$. It remains in a coherent state only if you think that the radiation field is fully described by a single complex number.

Electromagnetic radiation certainly exists, but is not usefully described as "made of photons" except in a very vague and heuristic sense that is seldom useful for actually making predictions.

Even the Nobel prize committee recognized the usefulness of Einstein's "heuristic viewpoint".

You haven't really explained why "photon" is such a taboo-word for you. You are insisting on terminology that is your own, and certainly not mainstream.

 

[PeterDonis]

Gamma-ray astronomers have no qualms expressing their results as photon fluxes.

Gamma rays are detected as discrete events because of their high energy, so the astronomers are just describing what they detect. You won't find optical or radio astronomers describing what they detect as photon fluxes.

It's the detector counts what they directly measure.

Exactly. And that claim is not a claim that the electromagnetic field they are detecting is made of "photons". It's just a description of counts of discrete detection events. Which is perfectly consistent with what I've been saying.

A coherent state is a theoretician's plaything, because it most closely resembles a classical field. The most common state encountered in nature is a thermal state

Which is, if anything, even less suited to a description in terms of "photons" than a coherent state.

detecting a photon changes the field state, decreasing its energy by $h \nu$.

Please give a specific reference to support this claim with regard to a thermal state of the EM field (or a coherent state, for that matter).

You haven't really explained why "photon" is such a taboo-word for you.

Yes, I have. I have explicitly said that the word "photon" is fine as a description of discrete detection events, but is not fine as a claim about the state of the EM field. It is very rare to encounter EM field states that are eigenstates of photon number, and only such states are usefully described in terms of "photons". Read my post #214 again: it's right there. You even quoted my statements to that effect.

 

[collinsmark]

Gamma rays are detected as discrete events because of their high energy, so the astronomers are just describing what they detect. You won't find optical or radio astronomers describing what they detect as photon fluxes.​

Not to be nitpicky here, but I think you'll find "photon flux" being spoken of in optical & near-infrared, particularly when discussing the sensor itself. Even in my backyard telescope, which I presently only use to take "pretty pictures" in optical wavelengths, it's essentially counting discrete photon detection events within a specified frequency bandwidth (once quantum efficiency is considered, which in my case can be as high as around 90%, depending on the camera I'm using; and a little ambiguity on top of that due to read noise).

That said, I think I agree with your general claims here. There are two points in-particular on which I'll elaborate:

(1) Photons cannot truly be treated as discrete particles (at least not in a non-lazy way) except at the detection event itself. As an example, take interferometry. The electromagnetic energy must be treated as wavelike up to the point of detection; otherwise interferometry (e.g., the Keck Interferometer and even the double slit experiment for that matter) wouldn't make any sense. But if you define "photons" in a non-lazy way, making them more nuanced quantum particles with both wavelike characteristics before detection and classical particle like properties at detection, then maybe that's what @WernerQH is getting at? I.e., A photon can still be called a "photon," even before detection: before its wavefunction has become an eigenstate of a detection event. It's just that in this sense, a "photon" is more nuanced than a classical particle.​

​

And with that, I should point out to @WernerQH, that if you define a photon in the more nuanced fashion, then all the nuance of it having wavelike properties (e.g., being in more than one place at any given time), is a mathematical artifact of quantum field theory (QFT). None of that nuance can be measured/observed directly.​

(2) I agree that radio astronomers don't describe individual photons that often.​

 

[PeterDonis]

I think you'll find "photon flux" being spoken of in optical & near-infrared, particularly when discussing the sensor itself.

Can you give a reference?

 

[PeterDonis]

After the measurements of the COBE, WMAP, and Planck satellites we even can assign a definite, five-digit number to the photon density of the cosmic microwave background.

Please give a specific reference that uses the term "photon density" in this context.

Why do you invariably (mis-)interpret any sentence containing the word "photon" as a statement about an abstract "state" of the electromagnetic field?

Because that's how you're using the term:

It is not unusual (and perfectly intelligible) to say that a photon carries a certain amount of energy $h\nu$ from the source to the detector.

This is a claim about the state of the electromagnetic field between the source and the detector. And unless the field is in a Fock state, it's a false claim.

Detecting a photon means that it is absorbed by an atom, exciting it to a higher energy level.

Not all photon detectors are single atoms where we measure a specific transition. In most cases we don't measure anything except a click or a dot, and we have no idea how specifically the photon got absorbed. We certainly don't always measure a specific transition frequency $\nu$. And as anyone who is familiar with QM should know, you have to be extremely careful making any claims at all about things that are not measured.

 

[collinsmark]

I think you'll find "photon flux" being spoken of in optical & near-infrared, particularly when discussing the sensor itself.

Can you give a reference?

Here's a few.

Wavefront sensing with prisms for astronomical imaging with adaptive optics
"A scenario where a read out noise of 5 electrons is also evaluated and the 3-sided prism WFS is found to have a Strehl ratio 12% higher than that of the pyramid WFS with a photon flux of 5 photons/subaperture/frame."

The Steward Observatory LEO Satellite Photometric Survey
"In addition to visual magnitudes, we also present two new metrics: the expected photon flux and the effective albedo. The expected photon flux metric assesses the potential impact on astronomy sensors by predicting the flux for a satellite trail in an image from a theoretical 1 m class telescope and sensor."

Here's one dealing with photosynthesis related sensors (not astronomy, but it is photon flux related):
Accuracy of quantum sensors measuring yield photon flux and photosynthetic photon flux
No quote necessary, since it's right there in the title.

Here's a product in industry:
Model PMA2132 Digital Quantum Light (PAR) Sensor
"Solar Light’s Model PMA2132 Digital Quantum Light (PAR) Sensor measures the photon flux in wavelength range from 400 to 700 nm."

 

[PeterDonis]

Here's a few

Thanks for the references. From what I can gather, these sensors are actually counting discrete detection events, and "photon flux" is counts per second (or counts per unit area per second). So as long as it is understood that "photon" means "discrete detection event", the use of the term is fine. None of these experiments, as far as I can tell, are on Fock states, so the EM field state would not be aptly described using the term "photon", but none of these references appear to be doing that.

 

[collinsmark]

Thanks for the references. From what I can gather, these sensors are actually counting discrete detection events, and "photon flux" is counts per second (or counts per unit area per second). So as long as it is understood that "photon" means "discrete detection event", the use of the term is fine. None of these experiments, as far as I can tell, are on Fock states, so the EM field state would not be aptly described using the term "photon", but none of these references appear to be doing that.

Yes, of course. They only measure discrete detection events. The same is true of the pixel elements in the sensor of my digital camera.

 

[collinsmark]

Forgive me, but I was sort of pulled into this thread by accident when my post from a different thread got moved here. So when I started commenting it was without the context of the whole first part of this thread. But now I do have a question.

None of these experiments, as far as I can tell, are on Fock states, so the EM field state would not be aptly described using the term "photon",

I'm led to believe that the bosonic creation and annihilation operators in QFT Fock states are non-Hermitian. Now, I'm not at all savvy with QFT (or Second Quantization, hence my question), but is the non-Hermitian property of these operators like that in standard QM, insofar that observable operators must be Hermitian?

I mean if this conversation is about directly observing the bosonic Fock state creation or annihilation, is that possible even in principle?

 

[PeterDonis]

I'm led to believe that the bosonic creation and annihilation operators in QFT Fock states are non-Hermitian.

That's correct.

is the non-Hermitian property of these operators like that in standard QM, insofar that observable operators must be Hermitian?

Yes. The creation and annihilation operators are not observables in themselves. However, there are observables that can be expressed in terms of them (for example, the canonical expressions for position and momentum operators in terms of creation and annihilation operators).

I mean if this conversation is about directly observing the bosonic Fock state creation or annihilation

It isn't. The point is simply that the Fock states are the only ones that are eigenstates of photon number, so they are the only ones that are properly described as consisting of "photons". Preparing such states, and observing them, is a hard experimental problem, but not insurmountable.

What we actually observe when we observe Fock states is an appropriate transition in the detector. The corresponding transition in the field itself is not observed; it is only inferred from the preparation and the detection.

We calibrate sources that prepare Fock states by doing quantum tomography on them--repeated measurements of different kinds to characterize the state that the source is preparing. For example, we can look for particular types of correlation or anti-correlation statistics that only Fock states can produce.

 

[davidespinosa]

Is there any actual discussion of Barandes' papers in this thread ?

It seems to me that the entire thread is off-topic, but I haven't read every single post.

 

[A. Neumaier]

Is there any actual discussion of Barandes' papers in this thread ?

It seems to me that the entire thread is off-topic, but I haven't read every single post.

Search for Barandes and you'll find the items. The papers are worthless, hence there is little to discuss.

 

[bob012345]

Search for Barandes and you'll find the items. The papers are worthless, hence there is little to discuss.

The guy is a physics professor and Co-Director of Graduate Studies for Physics at Harvard.

 

[RUTA]

Here is a long interview with Barandes by Curt Jaimungle that was posted just last week in case you're interested.

 

[gentzen]

https://www.astronews.com/community/threads/das-schicksal-von-schrödingers-katze.11585/post-144526

Vorschläge solcher stochastischen Prozesse kenne ich aus der Zeit vor Heisenbergs Durchbruch von 1925. Ich glaube ich habe ein altes Buch, wo Sir James Hopwood Jeans in seinem Beitrag einen solchen beschreibt: Statt einem beliegig unterteilbaren Zeitstrahl auf dem einzelne Ereignisse wie Sandkörner verteilt sind, stellt er sich die Quantenereignisse als unzerteilbare endlich ausgedehnte "Nadeln" vor.

I tried to look it up in the meantime, but haven't found it again yet. I am pretty certain now that it wasn't Sir James Hopwood Jeans, because I read all stuff that I have from him again now.

 

[gentzen]

Search for Barandes and you'll find the items. The papers are worthless, hence there is little to discuss.

I guess just as worthless as Bohmian mechanics, no?

 

[A. Neumaier]

The guy is a physics professor and Co-Director of Graduate Studies for Physics at Harvard.

Why should this matter? Only the contents counts, not the author. Even physicists at Harvard can write worthless papers.

 

[A. Neumaier]

I guess just as worthless as Bohmian mechanics, no?

Bohmian mechanics is at least useful in the nonrelativistic case, and doesn't claim more.
While Barandesian mechanics claims to be about the relativistic case but only consists of empty formalism.

 

[martinbn]

Bohmian mechanics is at least useful in the nonrelativistic case, and doesn't claim more.

Like what?! What is an example where it is useful?

 

[Fra]

Here is a long interview with Barandes by Curt Jaimungle that was posted just last week in case you're interested.

I skimmed this video, and my impression from post 117 stands.

What I find omitted from the analysis is how the actual inferences from input works. The problem with the abstractions where observational frames are replaced by equivalence classes is that you also detach yourself from the real inferences, and this is why the finetuning problem of unification only gets worse.

I like one thing about his thinking, the idea to reduce all "laws" to random transitions. It is close to my preferred views, and I see the potential explanatory value of this.

But what does this MEAN, where does these come from, are they emergent or fine tuned? For me, at least some wild ideas on this, is required to motivate the picture. And maybe Barande is thinking about this, I don't know, but I can't see it in the presentation. This is why i find that the ultimate motivator of for new perspective, is missing. This should come first, not afterwards?

/Fredrik

 

[A. Neumaier]

I guess just as worthless as Bohmian mechanics, no?

No. Bohmian mechanics is at least useful in the nonrelativistic case.

Like what?! What is an example where it is useful?

It is actually used for semiclassical numerical approximations of small quantum systems.

 

[martinbn]

No. Bohmian mechanics is at least useful in the nonrelativistic case.

It is actually used for semiclassical numerical approximations of small quantum systems.

But is it useful? There is a difference between used and useful.

 

[renormalize]

But is it useful? There is a difference between used and useful

I'm curious: can you explain this difference? Isn't anything that one can, and does, "use" be deemed "useful" by definition? Or do you imply that to be "useful" a method must somehow be "better" than alternatives that accomplish the same end result?

 

[bob012345]

Why should this matter? Only the contents counts, not the author. Even physicists at Harvard can write worthless papers.

And what makes it worthless if I might ask?

 

[Fra]

And what makes it worthless if I might ask?

As the we have different goals, I think the value of ideas are bound to be subjective.

Useful for what?

to reduce i-dont-fully-understand-qm-anxiety?

or

as hypothesis generation for solving any open, objective, problems?

In second sense i find MANY pure interpretations worthless too.

/Fredrik

 

[A. Neumaier]

And what makes it worthless if I might ask

See post #232.

 

[iste]

But what does this MEAN, where does these come from, are they emergent or fine tuned? For me, at least some wild ideas on this, is required to motivate the picture. And maybe Barande is thinking about this, I don't know, but I can't see it in the presentation. This is why i find that the ultimate motivator of for new perspective, is missing. This should come first, not afterwards?

He does touch on it briefly, effectively saying he doesn't know. But his thought is that maybe since the indivisible process is apparently so general, it makes sense that fundamental physics is rooted in the more general. I find this extremely weak. The mathematics of the stochastic mechanical models he distances himself from seems to allude to the idea that there is a profound connection between quantum effects (of all kinds, including Barandes' indivisibility) and the conservation of energy (and probability, momentum, etc. etc.) in the context of a stochastic system. That the latter causes the former seems the most parsimonious starting point of enquiry.

There is an interesting paper which I don't think is necessarily even correct but has strongly planted a seed in my mind:

https://scholar.google.co.uk/scholar?cluster=13745438883092622673&hl=en&as_sdt=0,5&as_vis=1

They claim , in the context of their construction, that by gerrymandering statistical particle ensembles to be conservative / non-dissipative / time-reversible they get non-locally mediated interference behaviors when you alter the environment for free due to the fact that changing the environmental configuration changes the trajectories moving through space and so necessarily changes the choices one must make to ensure conservative-ness. They say that their "trick" is non-Markovian which then reminds of the fact that classical hydrodynamic pilot-wave models produce quantum-like behaviors when their parameters are set so that the system dynamics are non-Markovian: e.g.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.7.093604
https://scholar.google.co.uk/scholar?cluster=16295625758829094935&hl=en&as_sdt=0,5&as_vis=1

So some interesting possible avenues.

 

[pines-demon]

Mods, can you edit the title of the thread to add the name of the author of the interpretation for future search? It is unclear what is being discussed here from the title alone.

 

[Fra]

He does touch on it briefly, effectively saying he doesn't know. But his thought is that maybe since the indivisible process is apparently so general, it makes sense that fundamental physics is rooted in the more general. I find this extremely weak.

Yes, it's weak indeed but that said I also see a deep connection, so beeing weak could means he has alot of work to be done before he wants to speak more?

I think this is at the heart not only of quantum mechanics but at the nature of causality and nature of physical law. I share his views up to this point.

I think of the conceptual link between "effects of isolation" on pre-correlated parts in your example, as well as in examples of "inside information" in market dynamics is most easily understood if you ask questions about causality not on system dynamics level, but on the relational levels of parts. This is how I understand that reason for non-markovian mechanisms, the "past" affects the future interactions because some information are not explicit in the state, but in the environment of the state, and hidden. This is also a key component in any emergence; the interplay between system and environment evolving.

I think non-divisibility is because, the causal stochastics is not naturally happening at the global system dynamics level; those laws are possibly and an artifact of the perspective of the external observer. And the systemet level markovian idea doesnt necessarily reflect the true causality (which noone yet understands of course). But the way Baranders speaks about observers makes me doubtful that he is envisioning this route.

/Fredrik

 

[PeterDonis]

Mods, can you edit the title of the thread to add the name of the author of the interpretation for future search?

The title has been edited to add the name of the interpretation. (The author's name is not really relevant, the key point is the name of the interpretation itself.)

 

[iste]

This is how I understand that reason for non-markovian mechanisms, the "past" affects the future interactions because some information are not explicit in the state, but in the environment of the state, and hidden. This is also a key component in any emergence; the interplay between system and environment evolving.

There is something kind of like that in the stochastic mechanical interpretation though from a very different perspective to yours. The particle is interacting with a background which is hidden insofar that it is not mentioned explicitly in quantum mechanics. It would be conservative interactions between particle and background which are related to the indivisibility.

those laws are possibly and an artifact of the perspective of the external observer. And the systemet level markovian idea doesnt necessarily reflect the true causality (which noone yet understands of course). But the way Baranders speaks about observers makes me doubtful that he is envisioning this route. /Fredrik

Yes; for Barandes, the external observer is explicitly modeled as part of the stochastic system.

 

[Fra]

There is something kind of like that in the stochastic mechanical interpretation though from a very different perspective to yours. The particle is interacting with a background which is hidden insofar that it is not mentioned explicitly in quantum mechanics. It would be conservative interactions between particle and background which are related to the indivisibility.

sounds like leading to via, embedding things in a bigger system. Ie. embedd the non-markovian interactions in a much larger system that is markovian?
for eample https://arxiv.org/abs/2005.00103 ?

This "type" of solution, which is also analogous to how one tries to make true evolution, as a simple entropic dynamics, has the same conceptual flaws and IMO will not solve the problem, without creating more and often bigger problems, which cripples the "explanatory value" of the constructions.

Yes; for Barandes, the external observer is explicitly modeled as part of the stochastic system.

Note sure what this means, did he elaborate more clearly on this somwhere that i missed when skimming?

For me "external observer" is an idealisation and fiction, it has a value to simplify models for small subsystem, but in realist, there are only internal obsevers.

But I think of "internal observers" as a kind of stochastic agents existing in and thus interacting with the environment, but the environment is unknown. But this observers is not "modelled" externally, only other internal observers can model other observers. And two internal observers have different views - non more right than the other one.

Rovelli has a nice quote in the context of this Relational QM (before he goes south...).

"Does this mean that there is no relation whatsoever between views of different observers? Certainly not..."
-- C. Rovelli, Relational Quantum Mechanics

"There is an important physical reason behind this fact: It is possible to compare different views, but the process of comparison is always a physical interaction"
-- C. Rovelli, Relational Quantum Mechanics

So the key question is again, what is the NATURE of this physical interaction? Rovellis answer, was - quantum mechanics. But this is a non-answer, as long as no-one understands quantum mechanics, but then again his interpretation served not to unifiy all interactions, it's mainly to build a quantum theory of gravity. (from there on he goes south IMO.. )

I think the key to the non-markovian nature here is the nature of this physical interaction. Embedding this in a bigger space, is cheating. We need to solve the problem without changing perspective, and that is how I envision a kind of stochastic process but taking place in an unknown space. So the space itself, is evolving as observer moves through it. Which is similar to how GR works. So there is interesting enough, conceptual similarities with the dynamics in space, and the evolution of space - and the stochastic processes in some space, and the evolution of this same space in the quantum foundations. Is it a coincidence? I suspect not? And this thing, is also I think exactly why the markovian divisibility isn't be true; there is "information" not only in the state, but in the state of the space as well, but I think not in the sense of a state embedded in a bigger one; that attempt of explanation totally misses the point of what is to be explained.

/Fredrik

 

[iste]

sounds like leading to via, embedding things in a bigger system. Ie. embedd the non-markovian interactions in a much larger system that is markovian?
for eample https://arxiv.org/abs/2005.00103 ?

This "type" of solution, which is also analogous to how one tries to make true evolution, as a simple entropic dynamics, has the same conceptual flaws and IMO will not solve the problem, without creating more and often bigger problems, which cripples the "explanatory value" of the constructions.

I don't know. I don't think so. It's just the most natural way of looking at the stochastic mechanics if you want an unextravagant description. The particles move randomly. Ideally, something must be causing their movement - like a dust particle getting disturbed by the background of molecules in a glass of water. The stochastic mechanical "osmotic velocity" directly corresponds to a component of momentum in quantum mechanics and got an interpretation due to comparison with Einstein Brownian motion - "velocity acquired by a Brownian particle, in equilibrium with respect to an external force, to balance the osmotic force". The external force is then attributed the background, causing the particle random motion. The particle naturally is acting back on the background (because where else is it going to go?) like your dust particle would in a glass of water, and the interplay leads to the osmotic velocity assuming that it leads to an equilibrium which would also conserve particle energy on average in its exchanges with its background environment. The osmotic energy is then mathematically responsible for quantum behavior and is required for energy conservation. This osmotic energy is just the same as the Bohmian quantum potential apart from the fact it is explicitly derived from the assumption of a diffusion which is non-dissipative, i.e. frictionless, time-reversible (albeit without explicit insight into an underlying microscopic model like for the dust particle suspended in water molecules - conservative diffusion seemingly seems sufficient as a constraint).

In the end what it looks like (crudely speaking) is: Lagrangian mechanics + noise = quantum mechanics, hence if you tone down the randomness, or alternatively are talking about objects that are far too big (purposefully ignoring their fine-grained descriptions) to noticeably feel random fluctuations of the background, you just get deterministic classical behavior.

So this background interaction thing is just a notable interpretation for what the mathematics in stochastic mechanics is saying. The classical hydrodynamic fluid bath mentioned earlier is a tempting way of looking at the stochastic mechanical background interaction because of how artificially countering viscous dissipation in those models leads the bath (i.e. background) to retain a memory of the events that interact with the bath, and leads to quantum-like, and seemingly non-local behavior. At the same time its an extremely tenuous link: these models still seem very different to the stochastic mechanical one, very less than perfect quantum analogs, highly fine-tuned with additional distracting components, not clear how similar it actually is at all - I very much have doubt. But the sentiment is vaguely similar to that of Ed Nelson in his book 'quantum fluctuations': "The particle doesn't know whether the other slit is open [or closed], but the background field does", and this isn't necessarily instantaneous either since these stochastic mechanical models seem to take finite amount of time for the system to settle into quantum equilibrium and show interference effects.

Note sure what this means, did he elaborate more clearly on this somwhere that i missed when skimming?

Well the observer is just referring to the measurement-dependence in quantum mechanics, right? In the Barandes model, that is all explicitly incorporated into the stochastic system so you have your observer system and whatever is being measured and then perhaps whatever else may be relevant, depending on scenario. Even though the observer disturbs the system it is observing (and momentarily reinstates Markovianity according to Barandes), there is only ever one definite classical-looking outcome (or set of outcomes) occurring at any given moment in time. The observer-dependence is just a special case of a phenonena that is generic to any interaction between different stochastic systems in the Barandes picture.

 

[mitchell porter]

Nelson's stochastic electrodynamics works because, like Bohmian mechanics, it's defined in configuration space, not physical space, so nonlocality is built in. Unfortunately from the discussion so far, I have no sense of how Barandes's mechanics works, what it lacks, and why he would think it enough to reproduce all the effects of entanglement...

 

[iste]

Nelson's stochastic electrodynamics works because, like Bohmian mechanics, it's defined in configuration space, not physical space, so nonlocality is built in. Unfortunately from the discussion so far, I have no sense of how Barandes's mechanics works, what it lacks, and why he would think it enough to reproduce all the effects of entanglement...

The assertion is that all quantum systems are equivalent to indivisible (also dubbed as 'generalized') stochastic systems - stochastic systems whose time-evolution cannot be arbitrarily divided up in terms of stochastic matrices for intermediate sub-intervals. Barandes' idea then is to show that any indivisible system is a subsystem of a unistochastic system, via something called the Stinespring Dilation Theorem. The unistochastic system can then be translated into a unitarily evolving quantum system in virtue of its definition. So the implication is that all of the behaviors of quantum systems should be expressible in terms of indivisible stochastic systems - or vice versa. For instance, the statistical discrepancy due to violations of divisibility  is interference, specifically corresponding to the kind of interference you would have for trajectories in the path integral formulation (I believe).

Barandes then describes a rudimentary entanglement entirely from the perspective of these indivisible stochastic systems that you can translate a quantum system into. Correlations from local interactions between different stochastic systems results in a non-factorizable composite system. The indivisibility of the composite stochastic system's transition matrix means that it cumulatively encodes statistical information so that the correlation is effectively remembered over time (even with spatial separation) until the composite system experiences a division event (i.e. decoheres and divisibility is momentarily restored) by interacting with another system. The mechanism of entanglement for the indivisibe stochastic system is then arguably due to non-Markovianity - memory - rather than some kind of overt communication.

 

[Fra]

Well the observer is just referring to the measurement-dependence in quantum mechanics, right? In the Barandes model, that is all explicitly incorporated into the stochastic system so you have your observer system and whatever is being measured and then perhaps whatever else may be relevant, depending on scenario. Even though the observer disturbs the system it is observing (and momentarily reinstates Markovianity according to Barandes),

The big problem in the inference picture not that the obserer distorts the system, but if you account for the systems back reaction on the observing context. This is trivial when the observing context is dominant. But when you add gravity, and want to understand unification without ad hoc fine tuning, this is the major problem; which I think suggest that we need to provide the other half of the story as well.

Ideally, something must be causing their movement -
...
The external force is then attributed the background, causing the particle random motion.

I get what you are saying and agree, but this is half the answer. My reactions are due to that we often seem that alot ot approached supply exactly that - only half the answer. This half of the answer represents the conventional external perspective, where "the whole macroscopic environment" observes a small subsystem (the quantum system). This conceptual framework works for small subsystems, which is where QM is corroborated as it stands.

But when the systems get big enough to cause non-trivial feedback into the "baground observer, macroscopic envirionment"; we tend to fall back to semiclassical models.

So half answer, can make us understand the action of small subsystem, embedded in a dominant context where we have perfect control; and the smaller subsystems we need to explain, the more finetuning to de need to make in the embedding, even to the point nwhere we can't handle it.

So the missing part of the answer is; what about trying to describe the situation from the inside. Then explanatory models can not be rooted in fictional background contexts. Randomness in this inside view rather does not need explanation, as somehow randomness is the "nullhypothesis", because the starting point is a simple stupid agent INSIDE a black box; not OUTSIDE the black box. On the contrary deviation from randomness is what needs to be "explained". And this is the missing part for me... and I couldn't see Barandes offering any new grips on this...

In my view, I do not think in terms of that "something" must be causing the random motion; I see this as artifacts of the external view.

I prefer to think that inside view is that the randomness is simply a manifestation of that the observes can not predict it - the obserever is indifferent to the cause because the mechanism can not be distinguished. This should even mean that the observers actions uncouple with these details; suggesting that that the phenomenology of interactions change as the observational scale does. The problem is that the explanatory power of normal renormalization flow works so that knowledge of a complex detailed microstructure of the macrostate "explains" the reduced interactions as you goto the macroscale. So it's redutionist in nature. But it offers littel insight into the emergence logic.

/Fredrik