Is action at a distance possible as envisaged by the EPR Paradox.

[pallidin]

Interesting thread. Hard to grasp at times.

 

[zonde]

Are you saying that John Bell was totally wrong, and Alain Aspect was totally stupid spending all this time & money in experimentally verifying that Bell's inequalities are physically violated??

No, I am not saying that.
Derivation of Bell inequalities is mathematically sound. And how else you would find out to what extent mathematical construction is applicable to physical situation without performing experiments?

Anyways if we allow the possibility that unfair sampling is justified assumption then Aspect experiment demonstrates that photon ensembles can have QM type properties that individual photons can't have. And finding that out wouldn't seem like waste of time and money.

 

[DrChinese]

I would add, Thomas, that a thread such as you describe exists... you were in it, and I believe you and DrChinese et al couldn't come to an agreement. If we're going to continue that discussion, lets, but starting from square one seems silly.

I seem to remember twisting around on this for an extended period of time. I think I got dizzy in the end.



So I am not sure I can survive another round. To sum up some of my comments quickly:

Please think of Bell's Theorem as a roadmap rather than a Bible. Bell charted the way for us. Once he showed us the way, we can accomplish all kinds of things with entanglement - all of which are completely consistent with garden variety quantum mechanics.

If you try to analyze Bell semantically, you will miss the point entirely.

 

[RUTA]

You do realize that everything you just said is in accord with the statement of mine you're disagreeing with? I'm saying that experiments, research, and theory are needed, not attempts at "Interpretations" of a theory that is clearly incomplete. I am, and have in the past here, argued for a semi-Instrumentalist approach, but with curiosity. I don't like the idea of these endless attemts to provide an ad hoc framework into which QM can be crammed.

I thought I made that clear in that other thread where I mentioned the need for an understanding of what occurs at and below the Planck Scale.

Many in the foundations community believe attempts to interpret quantum physics are a good way to look for a theory to complete quantum physics. For example, what makes you believe there's something relevant to completing quantum physics "at and below the Planck Scale?" You must have some implicit metaphysical "interpretation" of quantum physics that suggests the importance of this scale.

 

[DevilsAvocado]

... Anyways if we allow the possibility that unfair sampling is justified assumption then Aspect experiment demonstrates that photon ensembles can have QM type properties that individual photons can't have. And finding that out wouldn't seem like waste of time and money.

With all due respect, this is almost an even worse insult to Alain Aspect...

Would a member of the French Academy of Sciences and French Academy of Technologies, and professor at the Ecole Polytechnique, awarded with 2010 Wolf Prize in physics, spend all this time & money to find out that the detection efficiency is always less than 100% in optical experiments...!?

A high school student can figure this out by asking his teacher...

This is not a sound debate. To me, it seems like a classical example of "not seeing the forest for the trees"... among some.
This is not a question whether we can trust physical experiments involving photons; it’s a much bigger question.


Let’s take a step back - To clarify the background
(for pallidin et al.)

Albert Einstein was not perfectly happy with the non-causal nature of the new quantum physics, and he had an ongoing debate with Niels Bohr about this matter. Both were Nobel Laureates in Physics, and considered the brightest minds of their time (and history!).

To keep it short: Einstein favored 'real' particles like photons – Bohr was only interested in the wave function, or to be precise, the equations describing wave function.

In 1935, Albert Einstein published a paper, known as the EPR paradox, with the title; "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?". So far Niels Bohr, almost in triumph, had dismantled every argument from Einstein swift and easy. But this time it was different, Bohr’s reply was published five months later (with the exact same title as the original), and the paper implied he had misinterpreted the profound analysis of Einstein.

According to Einstein the EPR experiment yields a dichotomy, either:

1) A quantum system has a non-local effect on the physical reality.
2) Quantum mechanics is incomplete in the sense that some extra variable is needed to account for it.​

In 1964, John Bell showed (theoretically) that quantum mechanics predicts much stronger statistical correlations between the measurement results, than the theory of hidden variable is ever capable of.

Bell's theorem proves that every quantum theory must violate either locality or counterfactual definiteness (i.e. Heisenberg uncertainty principle; one cannot simultaneously know the position and momentum of a particle).

To make things even more 'contradictory' – we know that quantum mechanics and the predictions of quantum field theory (QFT) are the most precise in all of physics!

John Bell knew that there where theoretical escape routes from his theorem, e.g. Superdeterminism in which we (and the particles) lose our free will by the predetermined laws of physics, and become 18th century Laplace's demons.

And as discussed here, there are other interpretations of QM, like Many-worlds (MWI) where we split the whole universe for every particle in EPR, etc.
​

Now, with this in mind, it seems almost silly with all this focus on photons!? The brightest minds in history knew that EPR was an important and profound aspect of quantum mechanics.

And we are discussing unfair or fair sampling assumption of photons??

Well, that approach to EPR is certainly unfair to all the effort that has been made by a lot of very intelligent people, in nearly a century.

But, as I mentioned earlier, there are different kind of Bell test experiments performed – and to quit the discussion about 'unfair sampling', once and for all, we can point out the fact that in 2001 M. Rowe et al. conducted an experiment that used detection methods that were almost 100% efficient, thus avoiding the 'unfair sampling loophole', using two trapped ions:

http://www.nature.com/nature/journal/v409/n6822/abs/409791a0.html"

Fair sampling is a reasonable assumption and is therefore not a loophole.

Time to rethink.

"It is difficult for me to believe that quantum mechanics, working very well for currently practical set-ups, will nevertheless fail badly with improvements in counter efficiency ..." -- J.S. Bell

 

[Frame Dragger]

Many in the foundations community believe attempts to interpret quantum physics are a good way to look for a theory to complete quantum physics. For example, what makes you believe there's something relevant to completing quantum physics "at and below the Planck Scale?" You must have some implicit metaphysical "interpretation" of quantum physics that suggests the importance of this scale.

You are diverting my point, by raising another. Tit for Tat RUTA... "A cat for a hat, or a hat for a cat, but nothing for nothing."

As for the rest, why do you feel I have a metaphysical interpretation? I don't see that as a logical conclusion from the standpoint of wanting to see the two major theories of physics AGREE (i.e. GR/QM). As for believing that interpeting QM will lead to breakthroughs... I'm yet to see that. It DOES provide people with something to say other than, "we don't know"... a notoriously bad phrase to place in a grant request. Please don't assume what I "must" or must not believe.

 

[DevilsAvocado]

the standpoint of wanting to see the two major theories of physics AGREE (i.e. GR/QM)

YES! That 'gang' is definitely on my supporter-list!

 

[Frame Dragger]

YES! That 'gang' is definitely on my supporter-list!

Heh, thanks DA. I always was under the impression that, while it seems to always be an elusive goal, that having these two amazingly useful and predictive theories NOT dovetailing is... unacceptable. Perhaps that would be my "metaphysical" reason for wanting to understand the Planck scale...

Btw, great last post!

 

[DevilsAvocado]

Heh, thanks DA. I always was under the impression that, while it seems to always be an elusive goal, that having these two amazingly useful and predictive theories NOT dovetailing is... unacceptable. Perhaps that would be my "metaphysical" reason for wanting to understand the Planck scale...

Well, as we all know – It takes two to tango!
And it’s not always that bad move your a*s around in space-time to see what we’ll find!

Btw, great last post!

Thanks!

 

[hmm.max]

I would add, Thomas, that a thread such as you describe exists... you were in it, and I believe you and DrChinese et al couldn't come to an agreement. If we're going to continue that discussion, lets, but starting from square one seems silly.

As a reader of this thread, I would personally rather that ThomasT wasn't discouraged from participating in the conversation. As someone trying to understand the current state of affairs with "hidden variable theories", his comments were the only part of this thread that peaked my interest, i.e. the only statements that I had not already come across numerous times on this forum already.

Obviously, everything in this thread has already been discussed elsewhere. It seems very strange to me to suddenly single out someone who is drawing a very subtle distinction, and tell them to stop, in the midst of advanced discourse such as

"Are you saying that John Bell was totally wrong, and Alain Aspect was totally stupid.."

Not trying to be inflammatory, I just mean that this thread doesn't seem so sacred that shutting someone up is warranted.

 

[zonde]

Now, with this in mind, it seems almost silly with all this focus on photons!? The brightest minds in history knew that EPR was an important and profound aspect of quantum mechanics.

And we are discussing unfair or fair sampling assumption of photons??

Well, that approach to EPR is certainly unfair to all the effort that has been made by a lot of very intelligent people, in nearly a century.

This is unfair in respect to Many-worlds interpretation, right?
MWI is so exciting and how can it be compared with something as dull as unfair sampling.
But bear in mind that success of QM is actually success of "shut up and calculate" interpretation and the closest interpretation to this approach is Ensemble interpretation.

But, as I mentioned earlier, there are different kind of Bell test experiments performed – and to quit the discussion about 'unfair sampling', once and for all, we can point out the fact that in 2001 M. Rowe et al. conducted an experiment that used detection methods that were almost 100% efficient, thus avoiding the 'unfair sampling loophole', using two trapped ions:

http://www.nature.com/nature/journal/v409/n6822/abs/409791a0.html"

To consider this experiment as an EPR paradox test is a bit of stretch. EPR paradox considers separate measurements of two systems that are not interacting at the moment of measurement. But in this experiment there is only one joined measurement of both systems.

Fair sampling is a reasonable assumption and is therefore not a loophole.

Yes, in most cases fair sampling assumption is considered reasonable. But in this case fair sampling assumption necessarily comes packaged with one of the not-so-reasonable speculations like MWI, superdeterminism or nonlocality of Pilot-wave.
And in that light fair sampling is as reasonable as most reasonable one of those alternatives.

Time to rethink.

As you say

"It is difficult for me to believe that quantum mechanics, working very well for currently practical set-ups, will nevertheless fail badly with improvements in counter efficiency ..." -- J.S. Bell

When Bell said that? Definitely it was quite some time ago. And still there is uncomfortable lack of experiments that explicitly test what happens when counter efficiency is changed above usual ~10% level even when there is constant improvement in photon detection technologies.

 

[DevilsAvocado]

Please hmm.max, you are commenting Frame Dragger, but quoting me...

I would personally rather that ThomasT wasn't discouraged from participating in the conversation.

I have never discouraged ThomasT from participating in the conversation, in fact the contrary:

Time will definitely tell – and I hope I’m free to have my own view in the meantime.
You are free to have yours.

As someone trying to understand the current state of affairs with "hidden variable theories", his comments were the only part of this thread that peaked my interest, i.e. the only statements that I had not already come across numerous times on this forum already.

I do think you have misinterpreted ThomasT, he does not support "hidden variable theories", but he replaces it with his own version of "entanglement" (as far as I understand):

It's important to keep in mind that the entanglement correlations in Bell tests have to do with the relationship between the entangled entities. This relationship isn't the same as the hidden variable. It's a hidden, constant parameter that's assumed (in the QM treatment as well) to have a local cause.

It seems very strange to me to suddenly single out someone who is drawing a very subtle distinction, and tell them to stop, in the midst of advanced discourse such as

"Are you saying that John Bell was totally wrong, and Alain Aspect was totally stupid.."

I’m afraid you’re mixing persons, quotes and arguments into an unrecognizable clutter. The quote above was from me addressed to zoned, and not to the very subtle drawings of ThomasT.

that shutting someone up is warranted.

Wrong, but I think Frame Dragger can speak for himself.

 

[DrChinese]

As a reader of this thread, I would personally rather that ThomasT wasn't discouraged from participating in the conversation. As someone trying to understand the current state of affairs with "hidden variable theories", his comments were the only part of this thread that peaked my interest, i.e. the only statements that I had not already come across numerous times on this forum already.

I don't think anyone is trying to shut anyone up, but to be fair some of the discussion with ThomasT has been had multiple times previously. I for one don't want to repeat the exact same debate with the same person.

On the other hand: if you are interested in discussing any element of EPR/Bell, I am sure we would all be interested.

 

[DrChinese]

Well, as we all know – It takes two to tango!
And it’s not always that bad move your a*s around in space-time to see what we’ll find!

Thanks!

Just adding to what was said already: you had some great posts above... good stuff.

 

[DrChinese]

I do think you have misinterpreted ThomasT, he does not support "hidden variable theories", but he replaces it with his own version of "entanglement" (as far as I understand):

ThomasT has indicated previously that there are definitional issues with entanglement. I don't see those particular ones and neither do most folks. So it gets hard to have a discussion because his vewpoint hinders that. There is a generally accepted common ground to discuss these issues, and that usually goes all the way back to EPR.

 

[Deepak Kapur]

ThomasT has indicated previously that there are definitional issues with entanglement. I don't see those particular ones and neither do most folks. So it gets hard to have a discussion because his vewpoint hinders that. There is a generally accepted common ground to discuss these issues, and that usually goes all the way back to EPR.

I think that the real issue is with the definition of 'Local Realism'.

'Local Realism' assumes (as I feel about it):

1. Certainity is inherent in all the objects of nature (big or small). They always tend to 'possess' properties if someone tries/does not try to measure them.

2. Things/objects that are great distances apart (say light years apart in case of our Earth or say 100 feet apart in case of sub atomic particles, no proportion intended) don't get affected by other entities (especially when it come to the measurement of their properties).

In other words if we conduct any kind of measurement related to Earth, the effect of a star (say that is in the farthest corner of Andromeda galaxy) will not have any effect on this measurement.


I have a faint inclination that 'this star' will certainly have an influence on our measurement related to Earth (however small this effect may be). If an instrument could be formed that is (hyper)ⁿ sensitive, we may be able to gauge the effect. And it would depend on the (refinement)ⁿ/nature of our measurement wheter we take this effect to be of any consequence or not.

 

[Frame Dragger]

I think that the real issue is with the definition of 'Local Realism'.

'Local Realism' assumes (as I feel about it):

1. Certainity is inherent in all the objects of nature (big or small). They always tend to 'possess' properties if someone tries/does not try to measure them.

2. Things/objects that are great distances apart (say light years apart in case of our Earth or say 100 feet apart in case of sub atomic particles, no proportion intended) don't get affected by other entities (especially when it come to the measurement of their properties).

In other words if we conduct any kind of measurement related to Earth, the effect of a star (say that is in the farthest corner of Andromeda galaxy) will not have any effect on this measurement.


I have a faint inclination that 'this star' will certainly have an influence on our measurement related to Earth (however small this effect may be). If an instrument could be formed that is (hyper)ⁿ sensitive, we may be able to gauge the effect. And it would depend on the (refinement)ⁿ/nature of our measurement wheter we take this effect to be of any consequence or not.

That is a very long way of saying that you believe in Hidden Variables, but with the addition that you're speculating in a manner that has nothing to do with physics.

@hmm.max: I would respond, but DrChinese has done so quite nicely, as has DevilsAvocado.

 

[DevilsAvocado]

Just adding to what was said already: you had some great posts above... good stuff.

Thanks a lot DrChinese! I’m fairly new here, but I do understand you are the 'grandmaster' of EPR here on PF; therefore I’m now feeling something like this... + + + +

Thanks! ;)

 

[DevilsAvocado]

ThomasT has indicated previously that there are definitional issues with entanglement. I don't see those particular ones and neither do most folks. So it gets hard to have a discussion because his vewpoint hinders that. There is a generally accepted common ground to discuss these issues, and that usually goes all the way back to EPR.

Right, I cannot see how his 'local constant' can ever help him (even if entangled)... Maybe I misinterpreted ThomasT, or he has maybe misinterpreted some of EPR...

 

[DrChinese]

'Local Realism' assumes (as I feel about it):

1. Certainity is inherent in all the objects of nature (big or small). They always tend to 'possess' properties if someone tries/does not try to measure them.
...

There are 4 closely related terms, sometimes used interchangeably, sometimes used in the specific:

a. Realism - a la EPR's "elements of reality".
b. Hidden Variables - Essentially a deduction from realism.
c. Non-contextuality - the context of an experiment does not matter to the realism of an observable.
d. Counterfactual Definiteness - you can speak meaningfully about unmeasured observables.

I don't like to discuss the implications of the differences in these terms when discussing Bell or Aspect, because I think it leads to semantic arguments. For MOST purposes, I consider these terms interchangeable. So do most writers based on my readings, although there are a few who attempt to distinguish among them. Funny thing, the math is pretty much the same regardless. So too the predictions of QM.

 

[DrChinese]

Thanks a lot DrChinese! I’m fairly new here, but I do understand you are the 'grandmaster' of EPR here on PF; therefore I’m now feeling something like this... + + + +

Thanks! ;)

Between you, RUTA, FrameDragger, SpectraCat and a number of others (sorry if I left out your name too), I think we have seen some great additions around here. I consider the quality of the discussions to be inversely proportional to the number of ZapperZ posts! That meaning, in my book, that he does not need to pop in as much with his wise and informed comments.

 

[DevilsAvocado]

This is unfair in respect to Many-worlds interpretation, right?

Well... no, that’s actually not my point. To me it’s almost clear that EPR must be some kind of "gun smoke" of the next 'paradigm' in physics ('smoke' without 'fire'!? :uhh:). It’s a clear sign that we do not know everything there is to know, yet.

And I’m almost stunned by the numerous attempts to run "business as usual" – stating "well, this doesn’t mean anything... it’s a matter of QM interpretation", or "it’s hard to measure photons, therefore EPR is most probably misleading".

I don’t think that’s fair to all the intelligent persons that spent a lot of time working on this problem.

And if we look with some 'perspective' on the criticism of Bell test experiments – What are they saying? Well, most agree that Bell's theorem is correct and sound, but there is some "magical entangled loophole" that exposes itself in different ways, in different experiments!?

Yet we know that the 'overlapping effect' of all performed Bell test experiments, together with Bell's theorem is very convincing. And over time it will be definite.

I’m not an explicit supporter of MWI, it could be the correct solution, but I can’t get the 'pragmatic workings' of MWI into my head. Therefore I’m (for now) anticipating some hardnosed evidence from another 'branch'...

To consider this experiment as an EPR paradox test is a bit of stretch. EPR paradox considers separate measurements of two systems that are not interacting at the moment of measurement. But in this experiment there is only one joined measurement of both systems.

This is exactly what I’m talking about – the "magical entangled loophole"!

Yes, in most cases fair sampling assumption is considered reasonable. But in this case fair sampling assumption necessarily comes packaged with one of the not-so-reasonable speculations like MWI, superdeterminism or nonlocality of Pilot-wave.
And in that light fair sampling is as reasonable as most reasonable one of those alternatives.

Agree. It’s maybe not wise to deduce the problem of explaining EPR as an immediate proof of even weirder 'things'...

As you say

Welcome to the club!

When Bell said that? Definitely it was quite some time ago. And still there is uncomfortable lack of experiments that explicitly test what happens when counter efficiency is changed above usual ~10% level even when there is constant improvement in photon detection technologies.

Again, we have a very solid theory in Bell's theorem, and the experiments are improved day by day.
Where are the theories proving that it’s impossible to ever prove Bell's theorem? Any equations? Anything? Except opposition, and the "magical entangled loophole"...??

How would science look if we apply this 'approach' to everything else? Did the Big Bang really happen? Well, apparently not! No one was there to make the 'proper experiments', and the CMB is just a bunch of photons that we don’t know how to measure with 100% efficiency! Conclusion: Big Bang is not true, and we can explain everything we see with the "Turtle Interpretation"!

(to be drastic )

 

[DevilsAvocado]

... I consider the quality of the discussions to be inversely proportional to the number of ZapperZ posts!

:rofl:

 

[DevilsAvocado]

I think that the real issue is with the definition of 'Local Realism'.
...
I have a faint inclination that 'this star' will certainly have an influence on our measurement related to Earth (however small this effect may be). If an instrument could be formed that is (hyper)ⁿ sensitive, we may be able to gauge the effect. And it would depend on the (refinement)ⁿ/nature of our measurement wheter we take this effect to be of any consequence or not.

Deepak Kapur, I think the possibility for EPR to ever prove Local realism is almost zero, since it requires local hidden variables (as Frame Dragger & DrChinese already pointed out), and Bell has shown that quantum mechanics is not 'compatible' with LHV, and QM predictions are the most precise in all of physics.

Still, we can be pretty sure that the Moon is "out there" even when no one is observing it...

Or put it this way – if observations are required for distant stars and galaxies to be 'real' objects – we could today only observe galaxies as they appeared < 4.5 billion years ago, which of course is not true.

The farthest galaxies in this picture (the very faint red specks) are seen as they appeared more than 13 billion years ago.

It’s more than 'tough' to put macroscopic objects in superposition or entanglement, and this probably has something to do with the observed facts above... (= my speculation)

 

[zonde]

Well... no, that’s actually not my point. To me it’s almost clear that EPR must be some kind of "gun smoke" of the next 'paradigm' in physics ('smoke' without 'fire'!? :uhh:). It’s a clear sign that we do not know everything there is to know, yet.

And I’m almost stunned by the numerous attempts to run "business as usual" – stating "well, this doesn’t mean anything... it’s a matter of QM interpretation", or "it’s hard to measure photons, therefore EPR is most probably misleading".

To me it seems like you are contradicting yourself.
From one side you say that we do not know everything there is to know, yet.
From the other side you do not accept neither indirect modifications of QM - interpretations nor direct modifications of QM - position that QM is incomplete.

Or do you imply that we should modify anything but QM?

I don’t think that’s fair to all the intelligent persons that spent a lot of time working on this problem.

And I do not understand this completely.
Are you saying that if all those intelligent persons spent a lot of time working on this problem we shouldn't work on this problem any more and abandon it?

And if we look with some 'perspective' on the criticism of Bell test experiments – What are they saying? Well, most agree that Bell's theorem is correct and sound, but there is some "magical entangled loophole" that exposes itself in different ways, in different experiments!?

Yet we know that the 'overlapping effect' of all performed Bell test experiments, together with Bell's theorem is very convincing. And over time it will be definite.

I’m not an explicit supporter of MWI, it could be the correct solution, but I can’t get the 'pragmatic workings' of MWI into my head. Therefore I’m (for now) anticipating some hardnosed evidence from another 'branch'...

This is exactly what I’m talking about – the "magical entangled loophole"!

Interpretation of Rowe's experiment rests on assumption that photons scattered from two ions can not possibly interact (locally) as to change the count of photons that ends in detector. This assumption contradicts with results of double slit experiment not speaking about anything else.
There is no "magical entangled loophole" in Rowe's experiment just plain wrong assumption (even from perspective of QM).

Again, we have a very solid theory in Bell's theorem, and the experiments are improved day by day.
Where are the theories proving that it’s impossible to ever prove Bell's theorem? Any equations? Anything? Except opposition, and the "magical entangled loophole"...??

How would science look if we apply this 'approach' to everything else? Did the Big Bang really happen? Well, apparently not! No one was there to make the 'proper experiments', and the CMB is just a bunch of photons that we don’t know how to measure with 100% efficiency! Conclusion: Big Bang is not true, and we can explain everything we see with the "Turtle Interpretation"!

Science in general does not depend so much from "no go theorems" as Bell's theorem. There are quite different rules for theories that state "what can be" contrary to "what can't be".
If a theory states "what can be" given this and that it can be quite usable. And actually every theory has limited domain of applicability and still the science provides usable results.

 

[DrChinese]

Interpretation of Rowe's experiment rests on assumption that photons scattered from two ions can not possibly interact (locally) as to change the count of photons that ends in detector. This assumption contradicts with results of double slit experiment not speaking about anything else.
There is no "magical entangled loophole" in Rowe's experiment just plain wrong assumption (even from perspective of QM).

I just don't get this at all. You speak as if Rowe is the ONLY Bell test. We already knew that spacelike separation - what you are complaining about - makes no difference from Weihs et al (as well as Aspect). What Rowe shows is that the fair sampling assumption does not make any difference either.

As it stands, we have the following:

a) No individual Bell test "loopholes" exist.
b) No existing/remaining local realistic theory purports to replicate the predictions of QM and explain entanglement test results.

Some scientists hope to eventually close all loopholes simultaneously, although there are others who do not see this as anything other than desirable - so as to end further discussion of the matter by the few remaining local realists. (Like that would make any difference!)

 

[RUTA]

You are diverting my point, by raising another. Tit for Tat RUTA... "A cat for a hat, or a hat for a cat, but nothing for nothing."

Sorry, I was distracted and my latest post, plus some other quotes, were actually supposed to be in the first post. That's why the first post doesn't look like we had a disagreement. We do disagree on the value of time spent on interpretations. I believe it's valuable, while you don't find it particularly so. That's my understanding.

As for the rest, why do you feel I have a metaphysical interpretation?

You need to make ontological assumptions in order to map theory to experiment/experience, otherwise you're doing math, not physics. You can explore the mathematical consequences of equation X of theory Y, but to do physics, you would have to map those consequences to experiment/experience, which tacitly, if not explicitly, entails ontology (metaphysics). So, when you use the term "Planck scale" you've some ontological baggage if you're talking physics, not math.

I don't see that as a logical conclusion from the standpoint of wanting to see the two major theories of physics AGREE (i.e. GR/QM). As for believing that interpeting QM will lead to breakthroughs... I'm yet to see that. It DOES provide people with something to say other than, "we don't know"... a notoriously bad phrase to place in a grant request. Please don't assume what I "must" or must not believe.

You might read Gilder's "The Age of Entanglement" or Beller's "Quantum Dialogue" in order to appreciate the extent to which the development of quantum physics was tied to its interpretation. In reference to Beller's work, Smolin notes "there was not a single calculation in [Bohr's] notebooks, which were all verbal argument and pictures." [p 309 of Smolin's "The Trouble with Physics"]. Here is a quote fm Einstein writing to a young physics student (p. 310-11 in Smolin):

"I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science, So many people today -- and even professional scientists -- seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historical and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is -- in my opinion -- the mark of distinction between a mere artisan or specialist and a real seeker after truth."

Smolin goes on to argue for the importance of relating our formal approaches "to the older writings by physicists and philosophers on the big issues in the foundations of space, time, or quantum theory."

No one knows why QM and GR don't marry up. Those of us in foundations are compelled to search for the key to unification in, among other places, our ontological biases. Those who search in this area are of course very interested in "interpretations."

 

[ThomasT]

As a reader of this thread, I would personally rather that ThomasT wasn't discouraged from participating in the conversation.

Thanks, but I'm not discouraged.

As you've read, there's some disagreement regarding the title question of this thread. The fact of the matter is that what's called nonlocality or action at a distance (wrt EPR or Bell tests) comes from:

(1) deductions based on the data and associated instrument settings and/or,

(2) interpretations (the semantics) of the associated QM and/or Bell's theorem formalisms (Bell inequalities, GHZ, etc).

But none of it contradicts locality. Bell's theorem (via Bell inequalities, GHZ, etc.) is about formal constraints, not what does or doesn't exist in Nature.

 

[Frame Dragger]

Sorry, I was distracted and my latest post, plus some other quotes, were actually supposed to be in the first post. That's why the first post doesn't look like we had a disagreement. We do disagree on the value of time spent on interpretations. I believe it's valuable, while you don't find it particularly so. That's my understanding.




You need to make ontological assumptions in order to map theory to experiment/experience, otherwise you're doing math, not physics. You can explore the mathematical consequences of equation X of theory Y, but to do physics, you would have to map those consequences to experiment/experience, which tacitly, if not explicitly, entails ontology (metaphysics). So, when you use the term "Planck scale" you've some ontological baggage if you're talking physics, not math.



You might read Gilder's "The Age of Entanglement" or Beller's "Quantum Dialogue" in order to appreciate the extent to which the development of quantum physics was tied to its interpretation. In reference to Beller's work, Smolin notes "there was not a single calculation in [Bohr's] notebooks, which were all verbal argument and pictures." [p 309 of Smolin's "The Trouble with Physics"]. Here is a quote fm Einstein writing to a young physics student (p. 310-11 in Smolin):

"I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science, So many people today -- and even professional scientists -- seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historical and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is -- in my opinion -- the mark of distinction between a mere artisan or specialist and a real seeker after truth."

Smolin goes on to argue for the importance of relating our formal approaches "to the older writings by physicists and philosophers on the big issues in the foundations of space, time, or quantum theory."

No one knows why QM and GR don't marry up. Those of us in foundations are compelled to search for the key to unification in, among other places, our ontological biases. Those who search in this area are of course very interested in "interpretations."

Well, it seems we come from deeply different views on the matter, but then, I have the benefit of not being a physicist... a luxury really. I'm just trying to learn for the sake of learning, and I don't need to produce new theories. If I did, I WOULD probably stick to the math, but I wouldn't conclude that because X maps to y that it really has a physical reality.

I respect your approach, but I don't share it. I do see what you mean by bias however, so I think mine is: GR is wonderfully predictive, as in QM. I believe that modificationa and unification of both will reveal new physics. I have no CLUE as to what, except a hope that it explains a bit more.

@ThomasT: None of it contradicts Locality, but then you need a theory to compete with QM's predictions. So far, QM leads, with dBB being able to match the predictions. It's not enough to simply say that Bell doesn't rule out Locality, becuase it DOES if you accept the predictions of QM.

So, yes, bell is about constraints, but it is an EFFECTIVE constraint which has strangled all LHV theories that have been put forward.

 

[RUTA]

Well, it seems we come from deeply different views on the matter, but then, I have the benefit of not being a physicist... a luxury really. I'm just trying to learn for the sake of learning, and I don't need to produce new theories. If I did, I WOULD probably stick to the math, but I wouldn't conclude that because X maps to y that it really has a physical reality.

You hold the mainstream view. If you're interested in why that came to be the mainstream view, you can read either Gilder or Beller. But, rest assured, I'm the "quack" in this conversation, not you :-)

I respect your approach, but I don't share it. I do see what you mean by bias however, so I think mine is: GR is wonderfully predictive, as in QM. I believe that modificationa and unification of both will reveal new physics. I have no CLUE as to what, except a hope that it explains a bit more.

As an example of how one might use a QM interpretation to inspire an approach to unification, look up Hiley's recent work. In a summer 2009 preprint he writes,

"Since the advent of general relativity in which matter and geometry codetermine each other, there is a growing realisation that starting from an a priori given manifold in which we allow material processes to unfold is, at best, limited. Can we start from something more primitive from which both geometry and material process unfold together? The challenge is to find a formalism that would allow this to happen. In the early sixties David Bohm introduced the notion of a discrete structural process, [1], [2], in which he takes as basic, not matter or fields in space-time, but a notion of `structure process' from which the geometry of space-time and its relationship to matter emerge together providing a way that could underpin general relativity and quantum theory. Bohm provides a detailed discussion of the general notions implicit in this approach, but the problem of how to develop these ideas into a well defined mathematical structure remained unanswered."

In this paper he introduces what he hopes will serve as Bohm's missing mathematical structure. Just an example.

 

[DevilsAvocado]

To me it seems like you are contradicting yourself.
From one side you say that we do not know everything there is to know, yet.
From the other side you do not accept neither indirect modifications of QM - interpretations nor direct modifications of QM - position that QM is incomplete.

Or do you imply that we should modify anything but QM?

And the short answer is – I have absolutely no idea!

Seriously, let’s be honest, I’m only a layman with this as a hobby, and if I’d proclaim – "Hey guys! This is the way to do it! I got the final solution!" Then my claim in https://www.physicsforums.com/showpost.php?p=2675332&postcount=18" that "I’m not stupid", would most certainly be 'somewhat' questioned.

I do understand why you think I’m contradicting myself. My last post will not gain a 'rhetorical medal'... (under stress by 'reality', sorry)


Let’s do it right, let’s take one step back. In https://www.physicsforums.com/showpost.php?p=2679632&postcount=40" I pointed out Rowe as an example where the detection methods were almost 100% efficient, as a way of ending the discussion around the "Detection efficiency loophole" and "The fair sampling assumption". Your reaction was:

To consider this experiment as an EPR paradox test is a bit of stretch. EPR paradox considers separate measurements of two systems that are not interacting at the moment of measurement. But in this experiment there is only one joined measurement of both systems.

Then DrChinese hits the nail on the head (thanks DC!):

You speak as if Rowe is the ONLY Bell test.

If we also add this statement of yours:

Yes, in most cases fair sampling assumption is considered reasonable. But in this case fair sampling assumption necessarily comes packaged with one of the not-so-reasonable speculations like MWI, superdeterminism or nonlocality of Pilot-wave.

(emphasis by me)

Now, I hope I can explain, by the means of above, clearly what I’m arguing about:

To me, it seems as if there are two 'camps', struggling to 'get rid of' the EPR paradox (no offense!). One is the "Denial Camp" who tries with all means available to 'diminish' Bell's theorem and Bell test experiments, not to have to face the facts of even 'uglier beasts' like the MWI.

And the other is the "Interpretation Camp" who just loves freaky things – Is there a problem!? What problem?? We just sent it to a parallel universe! Let’s have dinner now... yawn.

(And then the public, who likes some 'excitement', but in the end always prefers to live in a 'logical world'.)

Get it?


Now back to DrChinese and Rowe. Do you really think it’s fair to avoid 'the sum' of all performed Bell test experiments? If we can rule out one loophole in one experiment, why do you insist on bringing it back in another? Is that really what 'the rules of science' tells you??

Is it healthy science to deny, in absurdity, the facts DrChinese points out??

As it stands, we have the following:

a) No individual Bell test "loopholes" exist.
b) No existing/remaining local realistic theory purports to replicate the predictions of QM and explain entanglement test results.

So what do I want!?

Well, to start with: Let’s throw the 'blinders' away. Let’s not have preconceptions. Let’s not explain 'weird things' with even 'weirder things', that can’t be physically proved in less than +1000 years. Let’s accept what nature shows us, even if it turns out 'crazy'. Let’s accept that the science of nature is not going to be completed in 2010. Let’s find the truth, if there is one.

We know that both QM & GR are very effective in respective domain, thus completely throw one or both out seems farfetched... even if String theory turns out to play the most beautiful music ever heard...


Footnote:
Doesn’t the Double-slit experiment 'crushes' the Ensemble Interpretation, by the footprint of the wave function in the interference pattern??

 

[DevilsAvocado]

We talk about moon becuase we see it the way our eyes/brains have been tuned to do so. Our instruments are also made/operated/analysed by our brains/eyes (that are tuned in a particular way).

It may be possible that moon/matter is not at all visible/detectable to someone from other stranger universe. (just foolish speculation with a small tinge of logic).

What would then become of our 'surity' about things.

Well, all this about 'personal interpretation' of the world is very true. Colors e.g. are only in our heads. In nature, there are only electromagnetic waves of different lengths.

But, you cannot avoid the fact that stars and galaxies evolves under a very long time, under gravity. And to make this argument even stronger: When the very first stars formed there where absolutely no life in the universe (to perform any observations)!

How do you explain that?

 

[Frame Dragger]

You hold the mainstream view. If you're interested in why that came to be the mainstream view, you can read either Gilder or Beller. But, rest assured, I'm the "quack" in this conversation, not you :-)

We don't agree, but if you're a quack then I'm the pope. As I'm not an old german man coming to grips with scandal, I suspect you're not a quack. I've read Gilder, not Beller (but I will now!), and I don't see how curiosity = quackery. You're not pushing a view, you're discussing it. I respect that.

As an example of how one might use a QM interpretation to inspire an approach to unification, look up Hiley's recent work. In a summer 2009 preprint he writes,

"Since the advent of general relativity in which matter and geometry codetermine each other, there is a growing realisation that starting from an a priori given manifold in which we allow material processes to unfold is, at best, limited. Can we start from something more primitive from which both geometry and material process unfold together? The challenge is to find a formalism that would allow this to happen. In the early sixties David Bohm introduced the notion of a discrete structural process, [1], [2], in which he takes as basic, not matter or fields in space-time, but a notion of `structure process' from which the geometry of space-time and its relationship to matter emerge together providing a way that could underpin general relativity and quantum theory. Bohm provides a detailed discussion of the general notions implicit in this approach, but the problem of how to develop these ideas into a well defined mathematical structure remained unanswered."

In this paper he introduces what he hopes will serve as Bohm's missing mathematical structure. Just an example.

I've read that (thanks to Demystifier and Zenith8, two very bright and interesting Bohmians here on PF), and I respect the goal. I think that a field with people taking different, but complementary approaches is a PLUS. This isn't fringe, anymore than EPR itself is "fringe". It's a well formulated objection to a formalism that is EFFECTIVE (mostly), but not satisfying or fully explanatory.

What can I say RUTA, you make a good case for your view, and I will continue to explore it. That said, I still maintain my formalism. I look forward to more of your posts.

 

[Frame Dragger]

And the short answer is – I have absolutely no idea!

Seriously, let’s be honest, I’m only a layman with this as a hobby, and if I’d proclaim – "Hey guys! This is the way to do it! I got the final solution!" Then my claim in https://www.physicsforums.com/showpost.php?p=2675332&postcount=18" that "I’m not stupid", would most certainly be 'somewhat' questioned.

I do understand why you think I’m contradicting myself. My last post will not gain a 'rhetorical medal'... (under stress by 'reality', sorry)


Let’s do it right, let’s take one step back. In https://www.physicsforums.com/showpost.php?p=2679632&postcount=40" I pointed out Rowe as an example where the detection methods were almost 100% efficient, as a way of ending the discussion around the "Detection efficiency loophole" and "The fair sampling assumption". Your reaction was:



Then DrChinese hits the nail on the head (thanks DC!):



If we also add this statement of yours:

(emphasis by me)

Now, I hope I can explain, by the means of above, clearly what I’m arguing about:

To me, it seems as if there are two 'camps', struggling to 'get rid of' the EPR paradox (no offense!). One is the "Denial Camp" who tries with all means available to 'diminish' Bell's theorem and Bell test experiments, not to have to face the facts of even 'uglier beasts' like the MWI.

And the other is the "Interpretation Camp" who just loves freaky things – Is there a problem!? What problem?? We just sent it to a parallel universe! Let’s have dinner now... yawn.

(And then the public, who likes some 'excitement', but in the end always prefers to live in a 'logical world'.)

Get it?


Now back to DrChinese and Rowe. Do you really think it’s fair to avoid 'the sum' of all performed Bell test experiments? If we can rule out one loophole in one experiment, why do you insist on bringing it back in another? Is that really what 'the rules of science' tells you??

Is it healthy science to deny, in absurdity, the facts DrChinese points out??




So what do I want!?

Well, to start with: Let’s throw the 'blinders' away. Let’s not have preconceptions. Let’s not explain 'weird things' with even 'weirder things', that can’t be physically proved in less than +1000 years. Let’s accept what nature shows us, even if it turns out 'crazy'. Let’s accept that the science of nature is not going to be completed in 2010. Let’s find the truth, if there is one.

We know that both QM & GR are very effective in respective domain, thus completely throw one or both out seems farfetched... even if String theory turns out to play the most beautiful music ever heard...


Footnote:
Doesn’t the Double-slit experiment 'crushes' the Ensemble Interpretation, by the footprint of the wave function in the interference pattern??

Awesome post, and very clear. As to the footnote, I had this very argument (and "lost) with Zenith and Demystifier. The claim of dBB is that the interference is a function of the PILOT wave, which "guides" the particles. The particles themselves follow Classic Schrodinger trajectories. I don't believe this, but it matches the predictions of QM, so my belief is pretty irrelevant.

When it comes to dBB, you can't go wrong chatting with Zenith and/or Demystifier.

 

[Deepak Kapur]

Well, all this about 'personal interpretation' of the world is very true. Colors e.g. are only in our heads. In nature, there are only electromagnetic waves of different lengths.

But, you cannot avoid the fact that stars and galaxies evolves under a very long time, under gravity. And to make this argument even stronger: When the very first stars formed there where absolutely no life in the universe (to perform any observations)!

How do you explain that?

Actually, I was talking of a universe that is older/different/stranger than our own (I think this thing is not supported by the present super-structure of science).