Quantum Interpretation Poll (2011)

[A. Neumaier]

In that series of slides you write on p. 57-58,

It seems to me you completely misunderstand Bell's proof here. The proof deals with any theory where the specification of the state of a region of spacetime can be broken down into a set of local facts about the state of each point--what Bell called local "beables"--and where the state at each point in space and time can only be causally influenced by local states in the past light cone of that point. This would certainly apply to classical field theories like classical electromagnetism!

His particles are local but e/m waves are not.

My slides contain a setting in which the Bell inequalities can be violated although everything is described by the classical Maxwell equations. So whatever Bell's arguments are, they cannot be valid in this setting.

If you don't find the argument convincing, perhaps we could discuss it in more detail...

Please open a new thread for that...

 

[JesseM]

Please open a new thread for that...

OK, discussion continued on this thread.

 

[StevieTNZ]

Yeahhhh, voted! Only the 2nd person to choose that option, too. Out of a total of 33 votes so far.

 

[A. Neumaier]

Missed this above, yes I suppose it wasn't very polite, sorry for any offense, I thought it was kind of cute at the time, but I can see how it comes across as just plain rude.

It is easier to add missing information by just giving it, rather than by adding further derisive comments.

By the way, www.scholar.google.com refers like me to the arXiv pdf's rather than to the abstracts.

 

[A. Neumaier]

I have my own interpretation.

The thermal interpretation is superior to any I found in the literature, since it
-- acknowledges that there is only one world,
-- is observer-independent and hence free from subjective elements,
-- satisfies the principles of locality and Poincare invariance, as defined in relativistic quantum field theory,
-- is by design compatible with the classical ontology of ordinary thermodynamics
-- has no split between classical and quantum mechanics,
-- applies both to single quantum objects (like a quantum dot, the sun or the universe) and to statistical ensembles,
-- allows to derive Born's rule in the limit of a perfect von-Neumann measurement (the only case where Born's rule has empirical content),
-- has no collapse (except approximately in non-isolated subsystems).
-- uses no concepts beyond what is taught in every quantum mechanics course,
No other interpretation combines these merits.

A discussion forum for discussing the thermal interpretation has been approved:
https://www.physicsforums.com/showthread.php?t=490492
Please post your comments there.

 

[yoda jedi]

I think it's time for the annual quantum interpretation poll.

Vote for which interpretation you currently think represents reality.

a funny reading THE CHURCHES

http://arxiv.org/PS_cache/quant-ph/pdf/0205/0205039v1.pdf

..."You will find all the religions with all their priests pitted in holy war—the Bohmians [3], the Consistent Historians [4], the Transactionalists [5], the Spontaneous Collapseans [6], the Einselectionists [7], the Contextual Objectivists [8], the outright Everettics [9, 10], and many more beyond that. They all declare to see the light, the ultimate light. Each tells us that if we will accept their solution as our savior, then we too will see the light."


[3] J. T. Cushing, A. Fine, and S. Goldstein, editors, Bohmian Mechanics and Quantum Theory: An Appraisal, (Kluwer, Dordrecht, 1996).
[4] R. B. Griffiths and R. Omn`es, “Consistent Histories and QuantumMeasurements,” Phys. Today 52(8), 26–31 (1999).
[5] J. G. Cramer, “An Overview of the Transactional Interpretation of Quantum Mechanics,” Int. J. Theor. Phys. 27, 227–236 (1988).
[6] G. C. Ghirardi and P. Pearle, “Dynamical Reduction Theories: Changing Quantum Theory so the Statevector Represents Reality,” PSA 1990: Proceedings of the Biennial Meeting of the Philosophy of Science Association, Vol. I, edited by A. Fine, M. Forbes, and L. Wessels (Philosophy of Science Association, East Lansing, MI, 1990), pp. 19–34.
[7] W. H. Zurek, “Decoherence, Einselection and the Existential Interpretation (The Rough Guide),” Phil. Trans. R. Soc. Lond. A 356, 1793–1821 (1998).
[8] P. Grangier, “Contextual Objectivity: A Realistic Interpretation of Quantum Mechanics,” quant-ph/0012122; P. Grangier, “Reconstructing the Formalism of Quantum Mechanics in the ‘Contextual Objectivity’ Point of View,” quant-ph/0111154.
[9] D. Deutsch, The Fabric of Reality: The Science of Parallel Universes—and its Implications, (AllenLane, New York, 1997).
[10] L. Vaidman, “The Many-Worlds Interpretation of QuantumMechanics,” in The Stanford Encyclopedia of Philosophy (Summer 2002 Edition), edited by E. N. Zalta (Stanford University, Stanford, CA, 2002). Available at http:// plato.stanford.edu/entries/qm-manyworlds/.


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let there be light ! ...lol...
but maybe without hilbert space !



.

 

[Vectronix]

I also have my own interpretation, but I probably won't want to start a discussion about it unless people are super-interested... although my interpretation might be the thermal interpretation. [smiling] I'm definitely going to check out that thread at some point. Mine has the transactional interpretation somewhere at its core (or something very similar); I also interpret duality with the 'wave-only view' that I once read about somewhere. I don't think particles exist as such, to me, these are discrete, localized 'wave packets.' Using words that pertain to a corpuscular nature of these wave packets are a nice way of describing interactions though.

I did read in a book that I have that most scientists today consider the wave field described by the wave function as a real field (and thus it possesses energy and momentum).

 

[harrylin]

Thanks, very interesting poll results - apparently Copenhagen isn't really mainstream anymore; just many alternative opinions (which is scientifically a healthy thing).

Note: I did not know about Stochastic Mechanics, so I plan to read up on it
http://onlinelibrary.wiley.com/doi/10.1111/j.1749-6632.1986.tb12456.x/abstract

 

[Vectronix]

I always hated the Copenhagen interpretation.

 

[harrylin]

[..]
Deterministic chaos is an emergent feature of the thermal interpretation of quantum mechanics, obtained in a suitable approximation. Approximating a multiparticle system in a semiclassical way (mean field theory or a little beyond) gives an approximate deterministic system governing the dynamics of these expectations. This system is highly chaotic at high resolution. This chaoticity seems enough to enforce the probabilistic nature of the measurement apparatus. Neither an underlying exact deterministic dynamics nor an explicit dynamical collapse needs to be postulated.

The same system can be studied at different levels of resolution. When we model a dynamical system classically at high enough resolution, it must be modeled stochastically since the quantum uncertainties must be taken into account. But at a lower resolution, one can often neglect the stochastic part and the system becomes deterministic. If it were not so, we could not use any deterministic model at all in physics but we often do, with excellent success.

This also holds when the resulting deterministic system is chaotic. Indeed, all deterministic chaotic systems studied in practice are approximate only, because of quantum mechanics. If it were not so, we could not use any chaotic model at all in physics but we often do, with excellent success.

How is this thermal interpretation different from the stochastic mechanical interpretation?
Thanks,
Harald

 

[Rap]

2 for Copenhagen?
Who?

Me. Why would anyone vote differently?

 

[harrylin]

Me. Why would anyone vote differently?

Why anyone would have a different opinion than you? Probably because different people reason differently, based on different received ideas.

 

[yoda jedi]

I always hated the Copenhagen interpretation.

DEAD

..."that the Copenhagen (non-)Interpretation isn't tenable"...



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Now, "Psi-epistemic" models are the stuff (the modal approach).







.

 

[A. Neumaier]

How is this thermal interpretation different from the stochastic mechanical interpretation?
Thanks,
Harald

Read http://arnold-neumaier.at/ms/optslides.pdf
where the interpretation is explained. For more discussion, see the thread https://www.physicsforums.com/showthread.php?t=490492 , where you should also place further questions or comments.

 

[Rap]

Why anyone would have a different opinion than you? Probably because different people reason differently, based on different received ideas.

..."that the Copenhagen (non-)Interpretation isn't tenable"...

Ok, sorry, but seriously, what is the main objection to the Copenhagen interpretation?

 

[yoda jedi]

Ok, sorry, but seriously, what is the main objection to the Copenhagen interpretation?

.-the act of measurement is treated classically.

.-observer dependent.


if wave function is regarded as ontologically real, then, there is not need of observer, if the wave function is epistemic, less yet.




.

 

[rodsika]

.-the act of measurement is treated classically.

.-observer dependent.


if wave function is regarded as ontologically real, then, there is not need of observer, if the wave function is epistemic, less yet.




.

Isn't this weird? Copenhagen treats the wave function as calculation tool, but
when GRW treats it as real, they have to assume spontaneous collapse to avoid
observers. But how come the Copenhagen can get away by assuming it's observer
dependent and not spontaneous? In other words, why didn't the Copenhagen assume
the collapse is spontaneous too to avoid observer dependent?

 

[yoda jedi]

Isn't this weird? Copenhagen treats the wave function as calculation tool, but when GRW treats it as real, they have to assume spontaneous collapse to avoid observers * . But how come the Copenhagen can get away by assuming it's observer dependent and not spontaneous? In other words, why didn't the Copenhagen assume the collapse is spontaneous* too to avoid observer dependent?

*To avoid observers (or mesurements) just dropping the projection postulate is enough.

*Because copenhagen is based on linear schrodinger equation (standard quantum mechanics) and CSL (and other models) models are non linear.


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the projection postulate, which asserts that upon measurement of a physical system, its state will ‘collapse’ (or be ‘projected’) to a state corresponding to the value found in the measurement.

 

[rodsika]

*To avoid observers (or mesurements) just dropping the projection postulate is enough.

*Because copenhagen is based on linear schrodinger equation (standard quantum mechanics) and CSL (and other models) models are non linear.


----------
the projection postulate, which asserts that upon measurement of a physical system, its state will ‘collapse’ (or be ‘projected’) to a state corresponding to the value found in the measurement.

But there is still a possibility that the observer and projection postulate in Copenhagen can be literal, isn't it? (Copenhagen just assumes it's calculation aid... but there is possibility it is real). Or has this idea been totally refuted already? How?

 

[Rap]

.-the act of measurement is treated classically.
.-observer dependent.

These are not objections to Copenhagen, they are descriptions of Copenhagen. What is the objection?

if wave function is regarded as ontologically real, then, there is not need of observer, if the wave function is epistemic, less yet.

If I understand the terms "ontology" and "epistemology", I believe Copenhagen says they are neither. What is the objection?

 

[Matterwave]

Ensemble interpretation ftw!

 

[tom.stoer]

Ok, sorry, but seriously, what is the main objection to the Copenhagen interpretation?

It uses terms without defining them:
1) what is the "system", the "measurement device" and the "observer"?
2) how is the boundary between the "system", the "measurenent device" and the "observer" defined?
3) why is the "system (its wave function) treated quantum mechanically, whereas the measurement device is treated classically?
4) why is the usual time evolution unitary (via U), whereas the "evolution" of the system (its state) during the measurement process is non-unitary (collapse, no U, no time symmetry)?
5) the collaps seems to be problematic in a relativistic context

 

[rodsika]

It uses terms without defining them:
1) what is the "system", the "measurement device" and the "observer"?
2) how is the boundary between the "system", the "measurenent device" and the "observer" defined?
3) why is the "system (its wave function) treated quantum mechanically, whereas the measurement device is treated classically?
4) why is the usual time evolution unitary (via U), whereas the "evolution" of the system (its state) during the measurement process is non-unitary (collapse, no U, no time symmetry)?
5) the collaps seems to be problematic in a relativistic context

Does anyone know why in Copenhagen, the choice of what to measure determines what basis the quantum state will "collapse" onto a basis vector of?

 

[A. Neumaier]

It uses terms without defining them:
1) what is the "system", the "measurement device" and the "observer"?
2) how is the boundary between the "system", the "measurenent device" and the "observer" defined?
3) why is the "system (its wave function) treated quantum mechanically, whereas the measurement device is treated classically?
4) why is the usual time evolution unitary (via U), whereas the "evolution" of the system (its state) during the measurement process is non-unitary (collapse, no U, no time symmetry)?
5) the collaps seems to be problematic in a relativistic context

Do you know an interpretation that defines all its terms? (I don't know any though my thermal interpretation comes close to this ideal. Discussion of that please in https://www.physicsforums.com/showthread.php?t=490492 )

Relativistic collapse is treated adequaely in papers by Peres on relativistic measuremnt.

4. is because when observing a system, the system is not closed, hence not described unitarily.

The _only_ blemishes of the Copenhagen interpretation are that it cannot derive the collapse and needs to restrict attention to systems observed from the outside. Most other interpretastions have far worse problems.

 

[tom.stoer]

Do you know an interpretation that defines all its terms?

No.

4. is because when observing a system, the system is not closed, hence not described unitarily.

But there is no way to describe the system "system + device + observer" unitarily, either.

 

[Rap]

It uses terms without defining them:
1) what is the "system", the "measurement device" and the "observer"?
2) how is the boundary between the "system", the "measurenent device" and the "observer" defined?
3) why is the "system (its wave function) treated quantum mechanically, whereas the measurement device is treated classically?
4) why is the usual time evolution unitary (via U), whereas the "evolution" of the system (its state) during the measurement process is non-unitary (collapse, no U, no time symmetry)?
5) the collaps seems to be problematic in a relativistic context

Regarding 1, 2, and 3, the boundary is described by the decoherence approximation. Its like asking what is the boundary between the microscopic and macroscopic in statistical mechanics. Regarding 4, how is this an objection? What inconsistency is introduced by this fact?. Regarding 5, I would be interested in knowing what the problem is.

 

[rodsika]

Fyzix and others, you miss something very important. In Heisenberg interpretation, the unmeasured world ACTUALLY is what quantum theory represents it to be: a superposition of mere possibilities (Heisenberg called them potentia), unrealized tendencies for action. Nick said "an unobserved quantum entity possesses "more reality" than that available to ordinary objects because it can entertain in potentia a multitude of contradictory attributes which would be impossible for any fully actualized entity." That's right. And the magic of measurement grants one of these tendencies a more concentrate style of being.

What is a measurement? It bridges the worlds between Potentia and our concrete world. Measurement is like open sesame.. as fundamental as Space and Time.

This makes more sense than the superposition representing superpositions of universes in Many Worlds or mere calculational device in Copenhagen.

Heisenberg is the way to go. It's more likely than Many Worlds. If anyone can refute Heisenberg Potentia, please do it now before I got into Potentia mania. My question is. Before measurement, decoherence can influence the particles.. so what does it mean it is located in Potentia? Does this refute Heisenberg Intepretation?

 

[JesseM]

Fyzix and others, you miss something very important. In Heisenberg interpretation, the unmeasured world ACTUALLY is what quantum theory represents it to be: a superposition of mere possibilities (Heisenberg called them potentia), unrealized tendencies for action. Nick said "an unobserved quantum entity possesses "more reality" than that available to ordinary objects because it can entertain in potentia a multitude of contradictory attributes which would be impossible for any fully actualized entity." That's right. And the magic of measurement grants one of these tendencies a more concentrate style of being.

What is a measurement? It bridges the worlds between Potentia and our concrete world. Measurement is like open sesame.. as fundamental as Space and Time.

I haven't heard of this Heisenberg interpretation, do you have a link? What defines a "measurement"? Could a machine make a measurement (even a hypothetical nano-machine) or can only humans do it? And what do you think of the point I made [post=3252397]here[/post] about the inelegance of treating collapse due to measurement as "real"?

The idea that collapse could be "real" just seems sort of silly to me given what's known about decoherence, since we know if we have an experiment where a quantum system interacts with a bunch of measuring-device like systems which leave some sort of records of their results, and we model all these interactions using deterministic wavefunction evolution and only at the very end do we apply "collapse", the records will show something that looks precisely like a series of earlier "collapses" even though in our model it was just decoherence. The idea that you could have this weird hybrid of "real collapse" and decoherence which, upon collapse of measurement records yields records that look precisely identical to those caused by real collapse, just seems way to contrived and coincidental to be plausible to me.

 

[rodsika]

I haven't heard of this Heisenberg interpretation, do you have a link? What defines a "measurement"? Could a machine make a measurement (even a hypothetical nano-machine) or can only humans do it? And what do you think of the point I made [post=3252397]here[/post] about the inelegance of treating collapse due to measurement as "real"?

The Heiserberg Interpetation is in Nick Herbert book called "Quantum Reality". Nick said:

"Quantum Reality #8. The duplex world of Werner Heisenberg (The world is twofold, consisting of potentials and actualities) Most physicists believe in the Copenhagen interpretation, which states that there is no deep reality (QR #1) and observation creates reality (QR #2). What these two realities have in common is the assertion that only phenomena are real; the world beneath phenomena is not.

One question which this position immediately brings to mind is this: "If observation creates reality, what does it create this reality out of? Are phenomena crated out of sheer nothingness or out of some more substantial stuff"" Since the nature of unmeasured reality is unobservable by definition, many physicists dismiss such questions as meaningless on pragmatic grounds.

However, since it describes measured reality with perfect exactness, quantum theory must contain some clues concerning the raw material out of which phenomena spring."

Try to read the rest at Amazon 30 page free views. Type Heisenberg or Quantum Reality #8 in the search bar inside the book page.

The logic is like this. In the deprived world of Copenhagen where they only know it as calculational tool, collapse may seem strange. But if you will treat the world as consisting of two realities... potentialities and concrete world. Then collapse is merely to change from potentialities to concrete world. Human observers are not required. Even hypothetical nano machines can do it. Just imagine the potentialities on the verge of orgasm. Measurement is just the release of it. This defines measurement or tendencies for release in any situation that calls for it. So what if collapse and born rule is arbitrary. Even our 20+ constants of nature is arbitrary. It's part of our world.

But I'm bothered by decoherence just like you described in the link you gave. But maybe the Potentialities is wave-like. So any wave from enivorment can affect it (the electron passing thru the gas decohering it). If we'd treat the Potentia as composing of waves. No problem about it. Heisenberg Interpretation is very intuitive and better than Many Worlds or plain deprived Copenhagen. Isn't it. What is your other objection to it.

 

[rodsika]

I haven't heard of this Heisenberg interpretation, do you have a link? What defines a "measurement"? Could a machine make a measurement (even a hypothetical nano-machine) or can only humans do it? And what do you think of the point I made [post=3252397]here[/post] about the inelegance of treating collapse due to measurement as "real"?

After more time in the internet. I found the original source of Heisenberg material. He published the book Physics and Philisophy in 1958 and the following paragraph in

http://www.marxists.org/reference/subject/philosophy/works/ge/heisenb3.htm

It is important and may be the source of his views or possible misinterpretation by physicsts like Nick Herbert and Henry Stapp. Therefore let us analyze it completely:

"Now, the theoretical interpretation of an experiment starts with the two steps that have been discussed. In the first step we have to describe the arrangement of the experiment, eventually combined with a first observation, in terms of classical physics and translate this description into a probability function. This probability function follows the laws of quantum theory, and its change in the course of time, which is continuous, can be calculated from the initial conditions; this is the second step. The probability function combines objective and subjective elements. It contains statements about possibilities or better tendencies ('potentia' in Aristotelian philosophy), and these statements are completely objective, they do not depend on any observer; and it contains statements about our knowledge of the system, which of course are subjective in so far as they may be different for different observers. In ideal cases the subjective element in the probability function may be practically negligible as compared with the objective one. The physicists then speak of a 'pure case'."

Now go to this http://fs-morente.filos.ucm.es/docentes/suarez/papers/SHPMP_Quantum propensities_May07.pdf where someone is analyzing it. She said:

"But a close reading of the book reveals a very complex mixture of interpretational elements, only some compatible with what we nowadays would identify as a Copenhagen interpretation. A commitment to reading the quantum probabilities at least in part in terms of Aristotelian potentialities stands out among the elements apparently alien to the Copenhagen view: ‘‘The probability function combines objective and subjective elements... "

The rest in in the quote above.

Now the most important question. Nick Herbert and Henry Stapp emphasized those "Potentia" are really there and not figurative. Pls. analyze unbiasedly. What do you think Heisenberg meant or the context of his statement? Do you think Heisenberg believed they are real or assumed the Potentia were possible?