I Can the PBR Theorem Prove the Reality of Quantum States?

[Demystifier]

This helps a bit. Can I look at it this way? In Newtonian gravity of point particles the theory says that each particle has a mass, which characterizes the particle's ability to interact with other particles, particles act on each other through forces, which depend on the masses and positions of the particles, the forces force the particles to move about on their trajectories and so on. In BM there are particles which together have a wave function, which is in some sense analogous to the masses, they act on each other via forces, which depend on the wave function in some way possibly on other things as well, those forces push the particles around on their trajectories and so on.

Yes, that's a nice way to look at it.

 

[Demystifier]

I hope Demystifier will mystify us once more

There is no demystification without prior mystification.

BTW, that's my 8000th post.

 

[vanhees71]

I already told you several times that their unobservability is analogous to unobservability of dark matter. Yet, not many physicists have problems with accepting dark matter as physical.

Wait, I thought it's NOT analogous. The hypothesis of the existence of dark matter is at least in principle subject to observational tests in the sense that you can find corresponding particles, and that's why there are many attempts to find such particles like WIMPs etc.

In BM, afaik the trajectories (in configuration space) are not observable in principle, and thus they cannot be subject to empirical testing to begin with. Otherwise BM gives the same probabilistic predictions as minimally interpreted QM. Thus the assumption of unobservable trajectories are just a philosohpical addition to make the theory look in some way "ontic", but there's no physics content in addition to QM in it.

 

[Boing3000]

BTW, that's my 8000th post.

And I hope not the last !

Can I ask you if my remarks in post #41 were missguided ?

 

[Demystifier]

Can I ask you if my remarks in post #41 were missguided ?

If your thoughts about BM are guided by claims of non-experts, then they are probably missguided.

 

[Demystifier]

Wait, I thought it's NOT analogous. The hypothesis of the existence of dark matter is at least in principle subject to observational tests in the sense that you can find corresponding particles, and that's why there are many attempts to find such particles like WIMPs etc.

If dark matter interacts only gravitationally, which is compatible with present observations, how would you observe them in principle?

In BM, afaik the trajectories (in configuration space) are not observable in principle,

Where does this principle come from? Do you think that it is a fundamental principle (like energy conservation) or emergent principle (like 2nd law of thermodynamics)? How robust do you think this principle is? ... And if your answer is "I don't know, I'm not an expert", then why are you so confident that they are not observable in principle?

 

[Boing3000]

No, they were OK. I didn't react because they were not addressed to me.

So I will assume that BM goal is to be more falsifiable than QM,making it a possibly more precise/complete theory...

I can only conclude from this statement that there is no correlation between differences in initial positions, and difference in final positions in BM. Rendering it un-physical/ un-falsifiable

Thus my conclusion must be false, meaning even if the correlation between initial (sensitivity to precision) and final position is chaotic (are they ?), they are in principle distinguishable from "true" randomness ?

 

[Boing3000]

If dark matter interacts only gravitationally, which is compatible with present observations, how would you observe them in principle?

You cannot observe it per say, but still can falsify it, by observing some configuration of matter that no amount of "dark" one would explain. But than GR is falsified too...

 

[Demystifier]

So I will assume that BM goal is to be more falsifiable than QM,making it a possibly more precise/complete theory...Thus my conclusion must be false, meaning even if the correlation between initial (sensitivity to precision) and final position is chaotic (are they ?), they are in principle distinguishable from "true" randomness ?

Sorry, my first reading of your text was not careful. In the meantime I totally changed my post #54. Yes, one of the motivations for BM is to have more precise/complete theory, but it does not necessarily mean more falsifiable. And yes, Bohmian trajectories are somewhat unpredictable in practice due to chaos-like reasons (even if this is not chaos in a strict technical sense).

 

[vanhees71]

Where does this principle come from? Do you think that it is a fundamental principle (like energy conservation) or emergent principle (like 2nd law of thermodynamics)? How robust do you think this principle is? ... And if your answer is "I don't know, I'm not an expert", then why are you so confident that they are not observable in principle?

Ok, then I misunderstood BM all my life. So do you say the trajectories are observable according to BM? Than it's clearly a different theory than QM and not the same as QM. I thought it was the point of de Broglie and Bohm, to provide just an alternative interpretation with keeping the physical outcome, i.e., observable predictions unaltered? I'm getting more and more confused.

I also wonder then, why nobody has ever tried to measure Bohm trajectories and test BM against QM then. Perhaps I should read a bit more in the book by Dürr et al...

 

[Demystifier]

Ok, then I misunderstood BM all my life. So do you say the trajectories are observable according to BM? Than it's clearly a different theory than QM and not the same as QM. I thought it was the point of de Broglie and Bohm, to provide just an alternative interpretation with keeping the physical outcome, i.e., observable predictions unaltered? I'm getting more and more confused.

I also wonder then, why nobody has ever tried to measure Bohm trajectories and test BM against QM then. Perhaps I should read a bit more in the book by Dürr et al...

I'm not claiming that Bohmian particles can be measured easily. I am just claiming that there is no exact absolute principle which forbids it. They are not measurable in the simplest minimal version of the theory, but the general framework is flexible enough to create a modified theory in which they can become measurable. The "problem" is that Bohmians (unlike BSM physicists) are typically not phenomenologists, so they are not much interested in producing an ad hoc modification just to make the theory testable. Yet, some ad hoc proposals exist.

 

[vanhees71]

Well, then they are mathematicians and no physicists!

 

[Demystifier]

Well, then they are mathematicians and no physicists!

Mathematicians would probably disagree, but I guess you think the same about string theorists.

 

[fanieh]

I agree with you that BM is probably incomplete. It this respect it is very similar to Newton theory of gravity, which is also non-local. Incompleteness is not a reason for a rejection.

Bohmians make the particle local.. but why don't Bohmians make the guiding wave real too? Even if the guiding wave is made real.. it should still follow the rule of the wave function that guiding waves (or wave function) of different objects are separate.. and entangled subsystem won't have wave function or guiding wave but only one guiding wave for the entire entangled system so this won't make the guiding wave superluminal violating relativity (or would it?) But yet the Bohmians don't want to make the guiding wave real or objective but only math. Is the reason because of relativity? But if there was a preferred frame of reference (for example the preferred frame uses some adS/CFT surface as preferred), then that means you can make the guiding wave objective too? Or still not and why not?I'd like to ask you something separate to the above. According to a pilot wave researcher, he uses the concept of duplex Reference Frame where there are two subspaces one of which is spacetime. Thus, as an approximation, one might consider it as a member of the general, eight-dimensional space. In this concept, the thing that makes this duplex RF unique and specific is that the other subspace is a reciprocal subspace to spacetime (imagine the momentum-space or Fourier transform of space and time function). Thus we have two potential four-dimensional subspaces; one is spacetime, the other is an actual reciprocal space (again composing of actual momentum space or Fourier transform of space and time function)...

Now in the double slit experiment and using that model. He suggested that in this duplex-space perspective, the slit structure itself, without the light waves, already has a Reciprocal space substance interference pattern existing around the slit regions of the ordinary spacetime structure. The model is that it is this reciprocal space pattern that guides the light into its maxima and minima ordinary space intensity locations behind the slits? Can you refute this? Or give other arguments that can refute this model? Thanks.

 

[Demystifier]

Bohmians make the particle local.. but why don't Bohmians make the guiding wave real too?

Because the wave does not live in ordinary 3-dimensional space. Analogy with HJ S-function or Newton gravity potential is again useful.

 

[fanieh]

Because the wave does not live in ordinary 3-dimensional space. Analogy with HJ S-function or Newton gravity potential is again useful.

Hamilton phase space doesn't live in ordinary 3-dimensional space too.. it's just a way to arrange information.. so for the BM guiding wave.. we can call it perhaps a force or something that is 3D yet described by wave function like any classical object can be described by Hamilton 3N phase space. so why can't the guiding force exist?

About the reciprocal space thing. The pilot wave author said every object has a reciprocal duplicate. I've been thinking about it for 12 years so if you have arguments that can refute it.. would thanks you hundredtimes.. thanks:)

 

[Demystifier]

Hamilton phase space doesn't live in ordinary 3-dimensional space too.. it's just a way to arrange information.. so for the BM guiding wave.. we can call it perhaps a force or something that is 3D yet described by wave function like any classical object can be described by Hamilton 3N phase space. so why can't the guiding force exist?

The guiding force exists. But just as in classical mechanics, the force is not a part of primitive ontology.

About the reciprocal space thing. The pilot wave author said every object has a reciprocal duplicate. I've been thinking about it for 12 years so if you have arguments that can refute it.. would thanks you hundredtimes.. thanks:)

I have no idea what is reciprocal duplicate.

 

[fanieh]

The guiding force exists. But just as in classical mechanics, the force is not a part of primitive ontology.

Hmm.. that's why we must make it QFT based so the force can be described. In classical mechanics, there is no strong force.. and even in QM, it can't be described. It can only be described by QFT.. you saying the guiding force is like this? Also are you simply referring to the guiding force as quantum potential?

I have no idea what is reciprocal duplicate.

It's simple. The inverse of distance is number per unit distance is spatial frequency, and the inverse of time is number per unit time is a temporal frequency.

You can you turn them into a four-dimensional subspace reference frame called wave number space and denoted by the vector Kx, Ky, Kz, Kt? The condense matter physicist with Ph.d. suggested there is an actual wave number space connected to our spacetime.. so every object has it.. and in the double slit experiment.. it has that actual wave number space too and the intereference patterns in the screen is simply the Fourier transform of the slits.. is this true?

 

[Demystifier]

Hmm.. that's why we must make it QFT based so the force can be described. In classical mechanics, there is no strong force.. and even in QM, it can't be described. It can only be described by QFT.. you saying the guiding force is like this?

Sort of.

Also are you simply referring to the guiding force as quantum potential?

Negative divergence of the quantum potential, to be more precise.

It's simple. The inverse of distance is number per unit distance is spatial frequency, and the inverse of time is number per unit time is a temporal frequency.

You can you turn them into a four-dimensional subspace reference frame called wave number space and denoted by the vector Kx, Ky, Kz, Kt? The condense matter physicist with Ph.d. suggested there is an actual wave number space connected to our spacetime.. so every object has it.. and in the double slit experiment.. it has that actual wave number space too and the intereference patterns in the screen is simply the Fourier transform of the slits.. is this true?

It is true that more-or-less any function f(x,t) can be Fourier transformed, but I'm not sure that it answers your question.

 

[fanieh]

Sort of.Negative divergence of the quantum potential, to be more precise.It is true that more-or-less any function f(x,t) can be Fourier transformed, but I'm not sure that it answers your question.

He is suggesting the pilot wave of our physical object is connected to another space (actual momentum space).. here are some illustrations:

Is it really true the interference pattern of the screen is the Fourier transform of the slits? If not true.. then it is refuted.. please let me know.. many thanks.

 

[Demystifier]

Is it really true the interference pattern of the screen is the Fourier transform of the slits?

It's true, that's a standard method in crystallography. That's also how the shape of DNA was discovered.

 

[fanieh]

It's true, that's a standard method in crystallography.

I just ordered the book Atlas of Optical Transforms this morning to see the other drawings because he got it from the Atlas book.
But he was suggesting that every object has a real momentum space counterpart.. so pilot wave of a particle is connected to the inverse spacetime. He said just as we have apples in our physical universe.. there is another apple in the inverse spacetime... and the two are coupled by something. In his experiments.. He can adjust the coupling such that he can make the thermodynamics of this physical spacetime be connected to the inverse spacetime so all his experiments show oscillations and that's how he concluded there was a real reciprocal spacetime. Are you saying this is also true? If not true, why not true?

 

[vanhees71]

Mathematicians would probably disagree, but I guess you think the same about string theorists.

I think, the string theorists are neither physicists (no interest in making predictions that can be empirically tested) nor mathematicians (lack of rigor). SCNR.

 

[Demystifier]

I just ordered the book Atlas of Optical Transforms this morning to see the other drawings because he got it from the Atlas book.
But he was suggesting that every object has a real momentum space counterpart.. so pilot wave of a particle is connected to the inverse spacetime. He said just as we have apples in our physical universe.. there is another apple in the inverse spacetime... and the two are coupled by something. In his experiments.. He can adjust the coupling such that he can make the thermodynamics of this physical spacetime be connected to the inverse spacetime so all his experiments show oscillations and that's how he concluded there was a real reciprocal spacetime. Are you saying this is also true? If not true, why not true?

I wouldn't say it's another apple in the inverse spacetime. I would say it's just another representation of the same apple.

I you are not too young, you have probably seen a negative of a photography, in which all colors are inverted. But it does not mean that there is another inverted you in an inverted universe. The above is similar.

 

[fanieh]

I wouldn't say it's another apple in the inverse spacetime. I would say it's just another representation of the same apple.

I you are not too young, you have probably seen a negative of a photography, in which all colors are inverted. But it does not mean that there is another inverted you in an inverted universe. The above is similar.

Thanks I got it now what is the conventional idea of this reciprocal space. He was also suggesting magnetic monopoles are located in this actual reciprocal space and he can make magnetic monopoles appear in his experiments. I think this is the part that is not true.

 

[Demystifier]

I think, the string theorists are neither physicists (no interest in making predictions that can be empirically tested) nor mathematicians (lack of rigor). SCNR.

So Bohmians are more rigorous than string theorists? Tell it to Lubos Motl!

Now more seriously. I don't think that there should be strict separation between physics, mathematics, philosophy, etc. It is perfectly natural and healthy to have interdisciplinary research which combines some (but not all) features of two or more fields. For instance, string theory combines some features of physics and mathematics; quantum foundations combines some features of physics, mathematics and philosophy, etc. The only condition is that researchers understand well all fields which they try to combine.

 

[Demystifier]

Thanks I got it now what is the conventional idea of this reciprocal space. He was also suggesting magnetic monopoles are located in this actual reciprocal space and he can make magnetic monopoles appear in his experiments. I think this is the part that is not true.

I guess it means that, in reciprocal space, electric charges look like magnetic monopoles. The emphasis is on look like.

 

[vanhees71]

Now more seriously. I don't think that there should be strict separation between physics, mathematics, philosophy, etc. It is perfectly natural and healthy to have interdisciplinary research which combines some (but not all) features of two or more fields. For instance, string theory combines some features of physics and mathematics; quantum foundations combines some features of physics, mathematics and philosophy, etc.

There cannot be a strict separation between physics and mathematics, but there must be a strict separation between physics and philosophy to make any progress in either of these fields.

I still don't know, whether I'm wrong in my claim that according to dBB the trajectories in configuration space are considered as unobservable (or "hidden") or not. If so, dBB is just the same as QT in its testable predictions and thus merely an interpretation with IMHO unnecessary complications. To calculate unobservable trajectories which don't help in predicting anything observable is just pointless from a physicist's point of view. It's maybe a nice mathematical exercise for bored QM students.

 

[fanieh]

I guess it means that, in reciprocal space, electric charges look like magnetic monopoles. The emphasis is on look like.

btw.. let me emphasize my questions:

Are you saying that if your perform Fourier transform of the 2 dots above.. it will produce the interference patterns at the bottom even without any light or electron passing thru the slits?

 

[vanhees71]

If nothing goes through the slits, you don't see any interference pattern. I think about this triviality even non-minimalistic philosophers agree. You cannot get an interference pattern by calculating a Fourier integral. The latter predicts the interference pattern in Fraunhofer observation based on some theory with wave equations (e.g., classical electrodynamics).

 

[Demystifier]

there must be a strict separation between physics and philosophy to make any progress in either of these fields.

Why do you think that philosophy cannot make progress by using insights from physics?

I still don't know, whether I'm wrong in my claim that according to dBB the trajectories in configuration space are considered as unobservable (or "hidden") or not.

In the simplest minimal version of dBB, you are right. But other versions are explored too.

If so, dBB is just the same as QT in its testable predictions and thus merely an interpretation with IMHO unnecessary complications.

It's unnecessary only if you don't think that there is the problem of measurement.

To calculate unobservable trajectories which don't help in predicting anything observable is just pointless from a physicist's point of view. It's maybe a nice mathematical exercise for bored QM students.

Bohmian trajectories are not only an interpretation, but also a practical tool. There are many cases in which calculation of trajectories actually helps to make measurable predictions.

 

[fanieh]

btw.. let me emphasize my questions:

View attachment 211086

Are you saying that if your perform Fourier transform of the 2 dots above.. it will produce the interference patterns at the bottom even without any light or electron passing thru the slits?

This is the person complete context of how it differs:

"Using this particular duplex-space perspective, one can see an entirely different explanation for the very famous Young's double slit experiment from the era of the classical mechanics paradigm. The conventional, single-space explanation (the old space and time explanation) saw the result as the interference of the light waves entering the two parallel slits. In that model, the slit structure itself contributes nothing but the two, parallel gap openings. This duplex-space perspective says the slit structure itself, without the light waves, already has an R-space substance interference pattern existing around the slit regions of the D-space structure. The model is that it is this reciprocal space pattern that guides the light into its maxima and minima ordinary space intensity locations behind the slits."

That's why I was asking if without any light entering the slits. Fourier transform of the slits can produce the same interference patterns that the particle is simply guided to the minima and maxima as described... can it?

 

[Demystifier]

Are you saying that if your perform Fourier transform of the 2 dots above.. it will produce the interference patterns at the bottom even without any light or electron passing thru the slits?

See the reply by @vanhees71 above.

 

[vanhees71]

Ok, perhaps I should give dBB a chance again and learn the details about it...

 

[fanieh]

If nothing goes through the slits, you don't see any interference pattern. I think about this triviality even non-minimalistic philosophers agree. You cannot get an interference pattern by calculating a Fourier integral. The latter predicts the interference pattern in Fraunhofer observation based on some theory with wave equations (e.g., classical electrodynamics).

What I meant was.. can you compute the interference patterns of the bottom based on the slit dimension itself? I know something has to go to the slits for the interference patterns to be visible but I was asking simply if the bottom is the Fourier transform of the top as in:

 

[Demystifier]

Ok, perhaps I should give dBB a chance again and learn the details about it...

Noooo, it wouldn't be you!

Seriously, if you are interested in actual applications of dBB as a practical tool, I can recommend you some literature which is pure science even by your standards.

 

[vanhees71]

Yes, pure science would be good, but isn't that textbook by Dürr good? I could omit the philosophy introduction easily ;-)).

 

[Demystifier]

Yes, pure science would be good, but isn't that textbook by Dürr good? I could omit the philosophy introduction easily ;-)).

The book by Dürr contains some rigorous mathematics (if this is what you want), but it does not discuss real applications.

For real applications see e.g. the books
https://www.amazon.com/dp/0387229647/?tag=pfamazon01-20
https://www.amazon.com/dp/3642180914/?tag=pfamazon01-20
https://www.amazon.com/dp/3642179738/?tag=pfamazon01-20

 

[fanieh]

See the reply by @vanhees71 above.

The person really said he can compute it by principle.
Look. This is all related to Pilot wave. It shows our pilot wave concept is still very incomplete. He shared this (is this the pre 1920 or 1927 deBroglie idea of pilot wave?):

About able to solve the Fourier transform in principle of any spacetime object. He wrote:

"A very important mathematical property of this particular duplex-space comprised of D-space and R-space, is that a unique quality in one subspace has an equilibrium quantitative connection to its conjugate quality in the reciprocal subspace. "
"This quantitative connection is called the equilibrium Fourier transform pair relationships. Thus, if you know a mathematical description of a quality in one subspace, you can, in principle calculate the equilibrium conjugate quality in the other subspace."
"in Figure 6.6b, the experimentally-generated diffraction pattern for a D-space hexagon of holes is given. To prove to the reader that the Fourier transform truly represents the diffraction pattern, we calculate the normalized R-space intensity (square of the amplitude) spectrum for this D-space hexagon of holes so as to compare it with the experimentally-generated diffraction pattern. Figure 6.7 shows this comparison and completely supports the assertion that the Fourier transform quantitatively reproduces the diffraction result of specific cases."

The following is computed:

So what I was asking is if anyone has also computed the pattern in principle too? Thanks.

 

[Demystifier]

@fanieh you didn't tell us the author and title of the book you are referring to.

 

[fanieh]

@fanieh you didn't tell us the author and title of the book you are referring to.

<Moderator's note: link removed>

 

[DrClaude]

That link is not an acceptable reference. Time to close the thread.