EPR Paradox Failure Explained for High Schoolers

[DevilsAvocado]

Not really sure what Zonde's saying in his post #54.

You’re not alone.

 

[nismaratwork]

First of all to test theory you have to make falsifiable prediction.
CHSH inequalities do not provide such prediction if you assume fair sampling. If CHSH inequalities are not violated it always can be asscribed to decoherence of entangled state.
So if you want to make falsifiable test you have to test fairness of sampling.

And that is what the article was about that ZapperZ mentioned.

Well DA and Dr. C beat me to the punch, so... what they said. Given how long this has been discussed, and how often you circle back to the same "points" you seem to be disingenuous. THe "article" btw, is just your stuff which ZapperZ didn't MENTION some article, he held you to PF guidelines regarding it... which it did not meet. I get it, you don't believe in fair sampling, but once you leave that small region which far from mainstream, you flail about and make truly absurd statements. I really don't know if you're just employing circular reasoning because you have nothing else and truly believe what you're saying, or if you are simply unwilling to say, "this is my opinion which I cannot adequately support".

ThomasT led with his philosophical view for a LOOONG time in that "other thread", but he openly admitted it. You just keep dancing around the central issue, and now you bring up decoherence in a fair sampling scenario which makes NO SENSE!

Dr. C: The "cited article" was already blown out of the water by ZapperZ, and therefore doesn't even require recognition, let alone discussion or citation!

 

[nismaratwork]

dx & DrC, or anyone else who knows what he’s talking about.

I have been thinking about the Heisenberg uncertainty principle. Could we make this analogy?

Assume we want to know the exact frequency of a sound wave at an exact moment. To determine the exact frequency it’s necessary to resample the signal over time and thus lose a degree of precision in the position. Therefore it’s impossible to get exact values for both, independently of measurement method.

This is not a problem for cars, humans, leopards or billiard balls etc, since they are well defined solid objects.

According to QM, all microscopic particles are to be treated as a wave function, or wave packet (before measurement):

[PLAIN]http://upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Wave_packet_%28no_dispersion%29.gif/300px-Wave_packet_%28no_dispersion%29.gif

Thus we will have exactly the same problem as with the sound wave. The position of a microscopic particle is uncertain – it could be anywhere along the wave packet.

The explicit premise of Hidden Variable interpretations is value definiteness:

All observables defined for a QM system have definite values at all times.​

Since we can easily see that the Heisenberg uncertainty principle exclude value definiteness all Hidden Variable interpretations are doomed.

Correct?

That's my understanding, and if there is something you're missing, I don't know what it is. Given that *turns to Dr. C and ZapperZ* I'll ask too... is that a fair understanding?

You’re not alone. :smile

I think I understand what he's saying, if I may be Zonde for a moment: "There is no such thing as fair sampling... everything I say comes back to that, even when I pretend that there is a situation where fair sampling is observed." If it isn't that, then it's just bad physics, instead of bad rhetoric.

 

[DevilsAvocado]

is that a fair understanding?

If we can get a little "philosophical" for a moment, personally I think all this and the history behind it is just amazing. Einstein’s discovery of the photoelectric effect led to the concept of wave–particle duality and the QM wave packet, which is what fundamentally caused all the problems for Einstein in the quest for the "Holy Grail" of a deterministic reality and causality.

Then Einstein fired off the EPR paradox, which boomeranged on him, now with an option of non-locality.

The big cosmological world was certainly on Einstein’s side, but that little microscopic devil seems to be laughing in his face constantly.

All because of these errant little waves.

The world is truly amazing and the final word is maybe not said...

I think I understand what he's saying

Well, so do I ... but after 1500 posts, it’s a complete mystery how he can mumble the same stuff over and over and over and over and over and over and over and over ... ∞ ??

 

[DrChinese]

I think I understand what he's saying, if I may be Zonde for a moment: "There is no such thing as fair sampling... everything I say comes back to that, even when I pretend that there is a situation where fair sampling is observed."

Again, not wanting to repeat the debates over a line of thinking that we've already discussed ad nauseum:

Fair sampling, as an assumption, is completely natural to make in experimental physics. Virtually any assertion of UNFAIR sampling - in which sample values are not sufficiently representative of the universe - can be demonstrated to be true or false when it comes to the physical world. So making such assertion is really going out on a limb.

The De Raedt team - the best I have seen to date - has worked long and hard on this (looking into fair sampling). Despite their interesting results, their computer simulations are far from shaking the infrastructure of Bell's Theorem and Bell tests. I know Zonde has done simulation work as well and is well aware of the complexity of the issue.

And that problem comes back to Bell's Theorem itself: there are severe limits on the overlap between local realistic predictions and actual Bell test results. De Raedt operates by attempting to provide something within the requirements of Bell but is just close enough to experimental results to appear viable. But some very unphysical assumptions are required to accomplish this. Again, this is something that is a recurring theme in this area.

So that is why I don't think Zonde is doing anyone a favor: he is trying to get "gullible" readers to accept something that at this point does not have any mainstream acceptance. As ZapperZ points out, that is outside PF guidelines. Such debate should not be presented here.

 

[nismaratwork]

Again, not wanting to repeat the debates over a line of thinking that we've already discussed ad nauseum:

Fair sampling, as an assumption, is completely natural to make in experimental physics. Virtually any assertion of UNFAIR sampling - in which sample values are not sufficiently representative of the universe - can be demonstrated to be true or false when it comes to the physical world. So making such assertion is really going out on a limb.

The De Raedt team - the best I have seen to date - has worked long and hard on this (looking into fair sampling). Despite their interesting results, their computer simulations are far from shaking the infrastructure of Bell's Theorem and Bell tests. I know Zonde has done simulation work as well and is well aware of the complexity of the issue.

And that problem comes back to Bell's Theorem itself: there are severe limits on the overlap between local realistic predictions and actual Bell test results. De Raedt operates by attempting to provide something within the requirements of Bell but is just close enough to experimental results to appear viable. But some very unphysical assumptions are required to accomplish this. Again, this is something that is a recurring theme in this area.

So that is why I don't think Zonde is doing anyone a favor: he is trying to get "gullible" readers to accept something that at this point does not have any mainstream acceptance. As ZapperZ points out, that is outside PF guidelines. Such debate should not be presented here.

I agree, and it's very tiring, but he gets away with it sans moderation so... the best that can be done is to challenge his assertions for the sake of any newcomers.

DevilsAvocado: Its amazing, and no wonder that Einstein, having just re-written how we see space, time, and gravity, would find it hard to swallow that 'upstart' theory. I wish he could have lived to see the experimental confirmation... our lifetimes are just too damned short.

 

[DevilsAvocado]

I wish he could have lived to see the experimental confirmation... our lifetimes are just too damned short.

Agree!

 

[VooDooX]

i have a question about the Heisenberg uncertainty principle i know it says the more precise one measurement the less precise the other can be but my question would be have they ever tried to measure both at the exact same nanosecond or smallest unit of time we can measure in ... the reason i ask is i assume these particles are moving very fast so even a small delay in measurements would skew the results anyone know anything abotu that?

 

[ThomasT]

A situation identical to EPR can be treated as follows: Take a diaprhram with two narrow slits, and let two particles of known momentum pass through them. If the momentum of the diaphragm is known exactly before and after the particles pass through, then A = p1 + p2 and B = q1 - q2 are exactly known, which is compatible with quantum mechanics since [A, B] = 0. Therefore, if we measure p1, then we know that p2 = B - p1. Or, if we measure q1, then we know q2 = q1 - A. So even though we are presented with a free choice of determining either p2 or q2, of the second system by measuring only the first system, q1 - A and B - p1 do not commute.

Ok, q2 and p2 don't commute. Neither do q1 and p1. But we actually measured q1 and p1 in the same trial on the same system. And considering any given trial,, as you noted, we can know (ie., deduce) q2 and p2, and this is compatible with qm -- ie., it isn't a violation of the hup. My thinking as to why it isn't a violation of the hup has been that it's because the hup doesn't apply to single trials where noncommuting measurements are made on spatially separated parts of an entangled system. That is, I've always thought of the deltas as referring to statistical spreads defined by actual measurements, not just the distribution defined by the wavefunction, because that's going to be the same for any trial in a given run, isn't it? And, to bring this home, since EPR is just dealing with the joint measurement in a single trial, then does the hup apply to EPR?

Anyway, to clarify my question regarding the hup and EPR: does the hup apply to single trials of the sort where, say, both the position and the momentum of an entangled system are being measured? If it doesn't, then I'm supposing that the hup simply doesn't apply to EPR. And if it doesn't, then the answer to the OP's first question is that EPR didn't violate or not violate the hup. It just didn't have anything to do with the hup -- for the (possible) reasons given. Or not?? I don't know for sure.

I'll address the rest of your post, sentence by sentence:

The point is that the criterion formulated by EPR is revealed to be ambiguous in light of the actual conditions that we are faced with in atomic physics, where concepts such as 'state' and 'behavior' cannot retain their usual meaning due to the existence of the quantum of action.

By "criterion formulated by EPR" I'm supposing that you're referring to their 'elements of reality', ie., that whatever can be predicted with certainty without disturbance must be a consequence of some underlying reality that exists prior to and independent of our probings of it. And yes, of course it has to be ambiguous. It can be reduced to the notion that the fact that detections happen at all is evidence of an underlying reality that exists prior to and independent of our probings of it. What about cloud chamber results? Or the tracks on photographic plates that particle accelerators produce? Isn't this evidence of an underlying reality that exists independent of our measurements of it?

I think that that's basically all that EPR was saying. Ie., that there's an ontological and epistemological realm underlying instrumental behavior, and qm isn't a complete description of it. One might say ... duh! But then, as the formulators of the Copenhagen Interpretation, and others, have pointed out, there's no way to unambiguously, objectively talk about an underlying realm.

So the quantum theory is about instrumental behavior. The quantum of action has to do with instrumental behavior.
And, since the hup has to do with the quantum of action, then the hup can't be interpreted as a statement about the underlying, or fundamental, behavior of our universe. It's only a quantitative statement regarding what we can say about what we know of the universe. And how do we know what we know?

The feature of individuality that underlies the comprehension of atomic phenomena is irrational within the scope of classical visualization and mode of explanation.

Not sure what you mean by this, but I'd say that our 'comprehension' of atomic phenomena, insofar as it can be called 'compehension', is entirely within the scope of, and mostly dependent on, classical modes of visualization and explanation.

However, any attempt of extrapolation of our causal spacetime description into the atomic domain must ultimately rest on the heavy scales and clocks, whose behavior is and must be accounted for classically. Thus in judging the form that such an extrapolation can take, we are essentially involved in an analysis of the possibilities of definition and observation, with due attention paid to the quantum of action, whose consideration is inevitable in any such analysis.

Ok, so I guess we agree on this.

Such an analysis, performed by Bohr, has shown that any situation which permits a causal account of a quantum process excludes a spacetime account of that process, and vice versa.

And this brings us back to the main message of the Copenhagen Interpretation. The formalism of qm doesn't necessarily correspond to what's actually happening in an underlying reality. It does, however, necessarily correspond to what's known about instrumental behavior.

Thus, the description of physical reality provided by quantum mechanics cannot be a causal-spacetime description, but a 'complementary' description, where the role of the measuring instruments is central. In fact, the quantum mechanical formalism must be viewed simply as a tool for such a complementarity description, whose well-defined application must always refer to the exact conditions of the experiment.

Well, I'd say that barebones qm doesn't provide, or even pretend to provide, a description of an underlying physical reality. So the fact that it isn't a "causal-spacetime description" of an underlying reality isn't really too surprising or upsetting. The role of measuring instruments and materials isn't just central, it's all there is as far as we can be, objectively, scientifically concerned. So, what you've said makes sense to me, and I agree with it, though I'd like to be able to say it in a briefer, simpler way. Is that possible?

 

[ThomasT]

The word "complete" in this context has always been a misnomer.

Well, qm is complete in one sense, and not complete in another sense. I don't think it's really a misnomer. Just depends on how one qualifies one's use of the term. For example, wrt the term nonlocality, one has to make it clear exactly what one is talking about to avoid confusion. The mainstream consensus on the meaning of the term, nonlocality, pertains solely to the formalism and has nothing to do with speculations regarding what is or isn't happening in nature. So when, eg., the OP of this thread asks a question about entangled particles communicating with each other, there should be a stock, reflex answer that entanglement has nothing to do with particles communicating with each other, but only to do with correlations in certain experiments and the associated formalism.

Anyway, I think that we think quite similarly about these topics even if one might not readily ascertain that from a casual reading of our interchanges. There have been some things you've presented that I thought were poppycock and certainly moreso, and rightly so wrt some of it but some of it remains unresolved, vice versa. But on the basics there's no disagreement. Local realism, of the usual sort, at least the Bell sort, is not an option. And what BI's and GHZ and Hardy, etc. theorems might be telling us about 'reality' -- I think nothing, but really I just don't yet feel that I understand them well enough to be able to say for sure.

 

[ThomasT]

Einstein tried to show that there is an underlying reality that has a causal explanation. The Heisenberg uncertainty principle states that this is impossible.

Hi DA, I love your scholarship. Keep it up. I'm learning from you. But I have some questions.

You quoted (from the PF definition I presume):

The Heisenberg uncertainty principle states that certain pairs of physical properties, such as position and momentum, cannot be simultaneously known to arbitrarily high precision.

And (from your line of reasoning):

Thus, if it is impossible to know the "whole world", not because of lack of precise measurements, but because of the nature of the system itself, we can hardly talk about "an element of a physical reality", right?

Ok, I don't get how the second statement above follows from the first. What is the first saying? Well, it's talking about the lack of arbitrarily high precision wrt measurements. So, the second statement would seem to conflict with the first since it seems to assert that the reason for this has to do with, not measurements, but some knowledge of the "nature of the system itself". However, it's quite well accepted that the hup doesn't have to do with the "nature of the system itself" but with, as mentioned in the first statement, the relationship between the precision of two canonically conjugate measurements. That is, we're never dealing with the nature of a system, but only with what we've measured wrt that system. And the hup says that multiple measurements of conjugate variables, x and y, of the same system will yield results consistent with (delta x) (delta y) >= h (or some appropriate variation thereof).

And I'm not even sure what "an element of a physical reality" per EPR means yet. But just consider an individual detection, of anything. Does it make sense to suppose that there was something that existed prior to detection, propagating from emitter to detector, in the transmission channels, that caused the detection event? If so, then isn't there an 'element of reality', even if we don't know exactly what it is and don't know exactly how to describe/define it, associated with ANY detection event?

Anyway, yes, I agree with you that an explicitly causal local realistic depiction of entanglement correlations is quite problematic. Impossible in certain, formal, respects. But, nevertheless, might well be the way the world works. Such is our ignorance.

Anyway, great post(s), and if I'm just not getting it then you can explain it to me.

By the way, will you take a shot at answering my specific questions/confusions regarding hup and EPR, and also what exactly jobsism is talking about?

 

[ThomasT]

You can' t say this unless you have proven non-locality. If you prove non-locality then you can say that EPR describes non-physical situation when they use idea that two entangled systems stop interacting when they are spatialy separated.

Can't say what? DrC didn't mention nonlocality. And, I just don't understand your second sentence. So, please explain. Thank you.

 

[ThomasT]

I have been thinking about the Heisenberg uncertainty principle. Could we make this analogy?

Yes, you can make that analogy. There's a time-energy uncertainty relationship wrt sound waves akin to the time-energy uncertainty relationship wrt matter or em waves.

But this ...

The explicit premise of Hidden Variable interpretations is value definiteness:

... isn't quite correct. There are several different sorts of local realistic models of entanglement. All of the ones that work, except for one (and it deals with a somewhat exotic and esoteric algebra), afaik, don't deal with definite values, but rather with a relationship between the entangled particles. Which, by the way, fits with the way I think about Bell experiments and correlations.

Since we can easily see that the Heisenberg uncertainty principle exclude value definiteness all Hidden Variable interpretations are doomed.

The hup doesn't exclude value definiteness. Every detection attribute is associated with a definite value. The hup states that, wrt a pair of conjugate variables, the product of the statistical spreads of the definite values of the two variables will be more than or equal to Planck's constant.

 

[ThomasT]

THe "article" btw, is just your stuff which ZapperZ didn't MENTION some article, he held you to PF guidelines regarding it... which it did not meet.

The article they were discussing was presented by ZapperZ. And it did meet PF guidelines in that it had been published in Phys. Rev. A, and DrC provided an arxiv.org link to it.

I get it, you don't believe in fair sampling, but once you leave that small region which far from mainstream, you flail about and make truly absurd statements. I really don't know if you're just employing circular reasoning because you have nothing else and truly believe what you're saying, or if you are simply unwilling to say, "this is my opinion which I cannot adequately support".

This sort of vitriol doesn't help to answer the OP's, or mine or others, questions. It's just nonspecific negative stuff that doesn't help clarify anything. I love having nice and interesting discussions about this sort of stuff. An exchange of ideas. Ok, maybe I was wrong about something, or you were wrong about something. Big deal. We talk about it. Maybe provide some links to papers. We all learn.

If you've got something specific to say about any of the considerations raised in this thread, then let's hear it. Otherwise, please, no more general negative (and personal) comments. It just disrupts the thread. Thank you.

By the way, I do think that the discussion of fair sampling wrt Bell tests is off topic wrt this thread. But I also think that some of Zonde's statements have been on topic and worthy of consideration. In fact, nismaratwork, he did sort of shut you down earlier, didn't he? Not that Zonde was right or wrong, but you didn't even respond to his refutation of your statement regarding what EPR was about -- which is on topic.

 

[nismaratwork]

The article they were discussing was presented by ZapperZ. And it did meet PF guidelines in that it had been published in Phys. Rev. A, and DrC provided an arxiv.org link to it.

This sort of vitriol doesn't help to answer the OP's, or mine or others, questions. It's just nonspecific negative stuff that doesn't help clarify anything. I love having nice and interesting discussions about this sort of stuff. An exchange of ideas. Ok, maybe I was wrong about something, or you were wrong about something. Big deal. We talk about it. Maybe provide some links to papers. We all learn.

If you've got something specific to say about any of the considerations raised in this thread, then let's hear it. Otherwise, please, no more general negative (and personal) comments. It just disrupts the thread. Thank you.

By the way, I do think that the discussion of fair sampling wrt Bell tests is off topic wrt this thread. But I also think that some of Zonde's statements have been on topic and worthy of consideration. In fact, nismaratwork, he did sort of shut you down earlier, didn't he? Not that Zonde was right or wrong, but you didn't even respond to his refutation of your statement regarding what EPR was about -- which is on topic.

If you believe that is vitriol, you don't understand what that word means. Beyond that, I'm thrilled that after 40 pages or so you've begun to learn you were wrong, believe me, it's exciting. It's one thing to be painfully mistaken or wedded to your philosophy, but as Dr. C pointed out, Zonde is probably not acting in good faith.

The OP has been answered in quite some depth, so I don't see what more can be said on the subject. By the time I got around to this thread, it was a matter of needing to point out that Zonde probably looks for converts more than he does for answers; not something that should be left unsaid for potentially novice readers.

Given your response to Dr. C, how is QM "complete in one sense, and incomplete in another", and what of his here did you find to be "poppycock"? Are you by chance referring to material int he same thread I culled the fair-sampling issue from, because if so, I find your post above downright amusing. In the vein of addressing EPR and ongoing issues here:

But this ...
... isn't quite correct. There are several different sorts of local realistic models of entanglement. All of the ones that work, except for one (and it deals with a somewhat exotic and esoteric algebra), afaik, don't deal with definite values, but rather with a relationship between the entangled particles. Which, by the way, fits with the way I think about Bell experiments and correlations.

Let me get this straight: are you claiming that there are local + realistic models which match the predictions of QM? If so, how, and if not... why bother bringing them up?

 

[zonde]

Well DA and Dr. C beat me to the punch, so... what they said. Given how long this has been discussed, and how often you circle back to the same "points" you seem to be disingenuous. THe "article" btw, is just your stuff which ZapperZ didn't MENTION some article, he held you to PF guidelines regarding it... which it did not meet. I get it, you don't believe in fair sampling, but once you leave that small region which far from mainstream, you flail about and make truly absurd statements. I really don't know if you're just employing circular reasoning because you have nothing else and truly believe what you're saying, or if you are simply unwilling to say, "this is my opinion which I cannot adequately support".

ThomasT led with his philosophical view for a LOOONG time in that "other thread", but he openly admitted it. You just keep dancing around the central issue, and now you bring up decoherence in a fair sampling scenario which makes NO SENSE!

Dr. C: The "cited article" was already blown out of the water by ZapperZ, and therefore doesn't even require recognition, let alone discussion or citation!

Your abilities to produce crap are admirable.
It was ZapperZ who brought up this article. Here is the quote:

So does that mean that you have written a rebuttal to D. W. Berry, et al., "Fair-sampling assumption is not necessary for testing local realism" Phys. Rev. A 81, 012109 (2010)?

Zz.

Here is the quote where ZapperZ metioned PF rules:

If you wish to keep using it, you must have it published. If not, I would strongly suggest that this should be the last time you refer to it, per our PF Rules.

Zz.

And here he was talking about my "counter example" and not about peer reviewed article that is published in respectable journal and that he himself brought up.

 

[zonde]

So that is why I don't think Zonde is doing anyone a favor: he is trying to get "gullible" readers to accept something that at this point does not have any mainstream acceptance. As ZapperZ points out, that is outside PF guidelines. Such debate should not be presented here.

Could you be more specific what is this "something" that does not have any mainstream acceptance? And plese do not hesitate to quote my posts.

Only thing ZapperZ pointed out was about my "counter example". And I explicitly pointed out that that is not the general direction I consider perspective i.e. LHV models that do not respect Uncertainty Principle.
ZapperZ didn't said anything about debates being outside PF guidelines. Or did I miss something?

 

[nismaratwork]

Your abilities to produce crap are admirable.
It was ZapperZ who brought up this article. Here is the quote:

Here is the quote where ZapperZ metioned PF rules:

And here he was talking about my "counter example" and not about peer reviewed article that is published in respectable journal and that he himself brought up.

Irony... anyway, I already admitted my mistake regarding the paper in this thread... in fact, in the thread right above the one I'm responding to. Now ThomasT, "Your ability to produce crap..." is an example of vitriol, in case you needed a reference.

So, back to the subject, you've never been much for offering alternatives, just harping on the notion that it's impossible for fair sampling to exist. I'm still curious where you feel decoherence comes into play... in fact, of all the questions you've been asked since your last post, you've essentially dodged them all, and simply responded to one mistake I made, and a painfully accurate statement by Dr. C. I don't suppose you have anything of substance to offer in regards to the actual questions asked by others, including ThomasT?

 

[zonde]

So, back to the subject, you've never been much for offering alternatives, just harping on the notion that it's impossible for fair sampling to exist. I'm still curious where you feel decoherence comes into play... in fact, of all the questions you've been asked since your last post, you've essentially dodged them all, and simply responded to one mistake I made, and a painfully accurate statement by Dr. C. I don't suppose you have anything of substance to offer in regards to the actual questions asked by others, including ThomasT?

You are again making statements without justification. To get back to the subject maybe try to formulate your statements as questions.
For example, you can ask if I think that it's imposible for fair sampling to exist.
I will gladly answer that no I don't but taking wider view on things I think that local realism exists. So if fair sampling in particular case conflicts with local realism then local realism takes precedence. But that is just my viewpoint and I do not say that anybody have to accept it.

If you are interested where do I see alternative I can try to describe it or point to some posts where I have tried to do that.

 

[DrChinese]

Could you be more specific what is this "something" that does not have any mainstream acceptance? And plese do not hesitate to quote my posts.

Zonde (#10): "I reject fair sampling assumption used in photon Bell tests. And without it they are not conclusive."

I am simply saying that you are entitled to your non-mainstream opinion. You are not entitled to debate it as if it is an open question in Physics. It isn't. All science assumes fair sampling unless and until a bias can be demonstrated.

---------------------------

For all readers:

Every form of every Bell test ever performed shows a violation of a related Bell Inequality. This confirms that there is no underlying physical bias which is somehow leading us astray.

Take any pair of non-commuting observables, and a sample of entangled pairs, and you will get this violation. Yet the same sample stream will indicate elements of reality as defined by EPR. This result directly contradicts EPR's assertion that the QM criterion for reality is unreasonably restrictive. In fact, it is completely reasonable to define elements of reality as ONLY being those that can SIMULTANEOUSLY predicted without disturbing the system. That would be 1 (completely certain) at a time, in accordance with the HUP.

Just as we measure the speed of light, or the attraction of gravity, or any other physical quantity: we do so by sampling, and we do so by repeating the experiment with different independent teams. Same with Bell tests, no difference at all. There is not ONE IOTA of evidence - NONE - that there is anything suppressing data which would yield a different conclusion were it detected.

Other than the hopes and wishes of Zonde and a few others, of course. No offense Zonde, I am just calling it for what it is.

 

[nismaratwork]

You are again making statements without justification. To get back to the subject maybe try to formulate your statements as questions.
For example, you can ask if I think that it's imposible for fair sampling to exist.
I will gladly answer that no I don't but taking wider view on things I think that local realism exists. So if fair sampling in particular case conflicts with local realism then local realism takes precedence. But that is just my viewpoint and I do not say that anybody have to accept it.

If you are interested where do I see alternative I can try to describe it or point to some posts where I have tried to do that.

At Bolded portion:

Zonde... let's just stop this. You believe something that, as Dr. C points out is on the absolute fringe of "science". You support this with nothing concrete except poor citations and your own writings, and as someone who read the EPR thread started by Deepak Kapur "cover to cover", you were a constant interruption in a fascinating discourse. Did it occur to you that more people read these threads than participate in them, and you're doing us all a disservice by pushing some personal agenda? I may not like ThomasT, or agree with him, but his views evolve to some extent... yours do not. You've taken every possible rational argument and dismissed it, flat-out avoided it, or you go ad hominem. When you start this up in a new thread, it's the responsibility of anyone who's familiar with your behavior to do what Dr. C has; warn readers who are NOT familiar with you, or the Bell ansatz, and EPR in general.

ThomasT has massive preconceived (or had depending on the day) notions about Bell, Aspect, EPR and more, but note that he still engages as best he can with Dr. C, DA, and dx. It's annoying to be so stubborn, but is it in bad faith?... I don't think so. I'm pretty sure you're just trying to sell something, and whether it's to reinforce your own beliefs, or for another reason, I can't guess.

You have never, in all that I've read, presented anything of sufficient substance to prove your belief that the fair-sampling bias is this pervasive thorn in the side of QM. You provide no concept of an alternative which is local and realistic, and makes the same predictions as QM and you've dismissed work by Aspect, and then Zellinger without anything I'd call backing. THOSE are statements without justification; I'm just calling it as I see it. I've READ your "alternatives", and read the responses from Dr. C and others blowing them out of the water... so sure, share them again and let's see if your personal theories meet PF guidelines with ZapperZ reading.

The bottom line here is that QM, as counter intuitive and weird as it can be, has made AMAZINGLY accurate predictions. The ONLY theory which can keep up (and only keep up, not exceed) is deBB, and it isn't local AND realistic either. If you want to be taken seriously, publish your "counter example" and get it peer reviewed, or show us a theory that can match QM and your criteria. Anything less is blowing smoke, and more of your cherry-picking single lines from extensive posts. Honestly, I'm amazed that you haven't been moderated in some way yet, and I can only assume it's because you're very careful to remain JUST on the right side of the rules, but you're butchering the spirit of them. I for one, am tired of it, and to see a guy like Dr. C lose HIS patience?... wow. He seems willing to teach pretty much anyone, anything he can... and even he's written you off as disingenuous.

So, EPR: I don't believe in "superdeterminism", I don't for a second buy the fair-sampling loophole argument, I find Dr. C's "Frankenstien" quartets very compelling as further argument against your points, and bottom line: QM, as ThomasT has said... may not be a perfect theory describing reality, but as of now, it's batting .1000. I finally understand why people say, "shut up and calculate"!

 

[zonde]

Zonde (#10): "I reject fair sampling assumption used in photon Bell tests. And without it they are not conclusive."

I am simply saying that you are entitled to your non-mainstream opinion. You are not entitled to debate it as if it is an open question in Physics. It isn't.

It is an open question.
From Weihs et al paper http://arxiv.org/abs/quant-ph/9810080"
"While our results confirm the quantum theoretical predictions, we admit that, however unlikely, local realistic or semi-classical interpretations are still possible. Contrary to all other statistical observations we would then have to assume that the sample of pairs registered is not a faithful representative of the whole ensemble emitted."

Can you provide arguments for your position?

All science assumes fair sampling unless and until a bias can be demonstrated.

All science relies on theories making positive predictions. Extensive usage of no-go theorems is quite specific trait of QM.

Besides, theorems like Bell theorem and CHSH inequalities do not confirm QM as it would be http://en.wikipedia.org/wiki/Affirming_the_consequent" fallacy. It's like that:
1. If prediction of QM is correct then Local Realism is violated.
2. Local Realism is violated.
3. Therefore prediction of QM is correct.

So assuming fair sampling does not help to confirm prediction of QM but it avoids falsification of QM prediction.
And that is not the way how all the science works. You can justify assumptions that help in confirmation of theory because then you can go further with the help of the theory. But you can't justify assumptions that prevent falsification of theory (without helping in confirmation).

Good example is relativity. Postulate of constancy of light is quite counterintuitive but it got remarkably wide acceptance because it allowed to make numer of new falsifiable predictions and later confirm them.
And what falsifiable predictions are made based on violation of local realism? Name one.

 

[DevilsAvocado]

It is an open question.
From Weihs et al paper http://arxiv.org/abs/quant-ph/9810080"
"While our results confirm the quantum theoretical predictions, we admit that, however unlikely, local realistic or semi-classical interpretations are still possible. CONTRARY TO *ALL* OTHER STATISTICAL OBSERVATIONS we would then have to assume that the sample of pairs registered is not a faithful representative of the whole ensemble emitted."

Can you provide arguments for your position?

(my emphasis)

zonde, please tell me you are joking, right? The arguments are provided, by you.

Besides, theorems like Bell theorem and CHSH inequalities do not confirm QM as it would be http://en.wikipedia.org/wiki/Affirming_the_consequent" fallacy. It's like that:
1. If prediction of QM is correct then Local Realism is violated.
2. Local Realism is violated.
3. Therefore prediction of QM is correct.

So assuming fair sampling does not help to confirm prediction of QM but it avoids falsification of QM prediction.

Again I think you have misunderstood the whole point. Bell's theorem is NOT about confirming QM. All it says is:

No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics.​

The picture you are trying to advocate makes you utterly alone and far out in your non-mainstream opinion. If we follow your logic – It’s an open question if QM is correct or not...!?!?

Could you at least give us the name of a competing theory that exceeds the http://en.wikipedia.org/wiki/Precision_tests_of_QED" of Quantum electrodynamics (QED), with a precision of ten parts in a billion (10⁻⁸)?

 

[DrChinese]

From Weihs et al paper http://arxiv.org/abs/quant-ph/9810080"
"While our results confirm the quantum theoretical predictions, we admit that, however unlikely, local realistic or semi-classical interpretations are still possible. Contrary to all other statistical observations we would then have to assume that the sample of pairs registered is not a faithful representative of the whole ensemble emitted."

Why do you keep it going? The above says it all: however unlikely... it is possible... And so are leprechauns. No evidence for them either.

By the way, your quote is a reference from 1998. I.e. prior to the generally accepted result of Rowe et al, which does NOT assume fair sampling. Same result.

 

[DrChinese]

And what falsifiable predictions are made based on violation of local realism? Name one.

There are probably hundreds of examples, variations on a theme:

How about entanglement of particles that have never existed in the same light cone? Not something you would expect in a local realistic universe. QM confirmed, LR rejected... again.

 

[DevilsAvocado]

For all readers: ...

Excellent explanation DrC!

 

[DevilsAvocado]

Hi DA, I love your scholarship. Keep it up.

Thanks! I will.

But I have some questions.

Why am I not surprised? Okay, fire off.

Ok, I don't get how the second statement above follows from the first. What is the first saying? Well, it's talking about the lack of arbitrarily high precision wrt measurements. So, the second statement would seem to conflict with the first since it seems to assert that the reason for this has to do with, not measurements, but some knowledge of the "nature of the system itself". However, it's quite well accepted that the hup doesn't have to do with the "nature of the system itself" but with, as mentioned in the first statement, the relationship between the precision of two canonically conjugate measurements. That is, we're never dealing with the nature of a system, but only with what we've measured wrt that system.

HUP is about the nature of the QM world. Counterfactual definiteness (CFD) is another word for objective Realism, i.e. the ability to assume the physical existence of objects and properties of objects defined, whether or not it is measured (or observed or not). If we interpret HUP as only a "measurement problem" – that the properties and the object is truly there, but damned thing doesn’t let us measure it – then you have to give up Locality, according to Bell's Theorem. (And to me, a non-local reality is as 'unreal' as a local non-reality...)

If you accept that QM is about probabilities (and not determinism), then the elementary events are not realized in actuality; otherwise the recourse to probabilities would be pointless. For instance, when you play lotto, you do not assume that all possible outcomes are actually realized, but only that one is actually realized.

And I'm not even sure what "an element of a physical reality" per EPR means yet.

The EPR paradox was a consequence of the debate between Bohr & Einstein, and two influential conceptions of fundamental physics; "Einstein realism" & "Bohr’s contextualism".

Einstein realism is the claim that a fundamental physical theory consist in the description of objects as they are independent of their being observed, in a causal and local theoretical scheme.

According Arthur Fine – "Einstein realism relies on two stringent criteria: observer-independence, and causality."

Albert Einstein – "Physics is an attempt conceptually to grasp reality as it is thought independently of its being observed."

The main feature of Einstein realism, observer-independence, can be translated into the following constraints, according to Matteo Smerlak:

Hypothesis 1
Value definiteness (VD): All observables defined for a quantum system have definite values at all times. More explicitely, there always exists a function, called a valuation function V , mapping any observable to a member of its spectrum, and representing the actual value of this observable.

In a world where VD holds, the following statement is fully justified:

Corollary 1
Counterfactual definiteness (CD): It is meaningful to speak of the definiteness of the outcome of a measurement, even if the latter is not actually performed.

The other essential aspect of observer-independence is non-contextuality, which means that:

Hypothesis 2
Non-contextuality (NC): If a QM system possesses a property (value of an observable), then it does so independently of any measurement context, i.e. independently of how that value is eventually measured.

In Einstein’s mind, the ‘observer-independent realm’ can hardly be conceived, unless it is prestructured by causality. This principle demands that:

Hypothesis 3
Causality: All fundamental laws should be deterministic. Accordingly, any fundamental theory should be free of probabilistic concepts.

Furthermore, Einstein’s realism relies on the locality principle, which roots the kinematical concepts of space and time in the very structure of physical reality:

Hypothesis 4
Locality: Physical processes unfold in the spacetime continuum in such a way that distant objects cannot have instantaneous mutual influence.​

By the way, will you take a shot at answering my specific questions/confusions regarding hup and EPR, and also what exactly jobsism is talking about?

Hope above helped in some way. I think jobsism is addressing this:

http://plato.stanford.edu/entries/bell-theorem/"

Bell's Theorem is the collective name for a family of results, all showing the impossibility of a Local Realistic interpretation of quantum mechanics. There are variants of the Theorem with different meanings of “Local Realistic.” In John S. Bell's pioneering paper of 1964 the realism consisted in postulating in addition to the quantum state a “complete state”, which determines the results of measurements on the system, either by assigning a value to the measured quantity that is revealed by the measurement regardless of the details of the measurement procedure, or by enabling the system to elicit a definite response whenever it is measured, but a response which may depend on the macroscopic features of the experimental arrangement or even on the complete state of the system together with that arrangement.
...
The refutation of the family of Local Realistic Theories would imply that certain peculiarities of Quantum Mechanics will remain part of our physical worldview: notably, the objective indefiniteness of properties, the indeterminacy of measurement results, and the tension between quantum nonlocality and the locality of Relativity Theory.

 

[DevilsAvocado]

But this ...
... isn't quite correct. There are several different sorts of local realistic models of entanglement. All of the ones that work, except for one (and it deals with a somewhat exotic and esoteric algebra), afaik, don't deal with definite values, but rather with a relationship between the entangled particles. Which, by the way, fits with the way I think about Bell experiments and correlations.

Well... okay, nonlocal dBB does a little 'trick' to qualify for value definiteness: "Not all observables defined in orthodox QM for a physical system are defined in Bohmian Mechanics, but those that are (i.e. only position) do have definite values at all times."

But are there other local realistic models?

The hup doesn't exclude value definiteness. Every detection attribute is associated with a definite value. The hup states that, wrt a pair of conjugate variables, the product of the statistical spreads of the definite values of the two variables will be more than or equal to Planck's constant.

See my previous post and you’ll realize this is reasoning is going to cause 'consistency trouble'.

 

[ThomasT]

There is not ONE IOTA of evidence - NONE - that there is anything suppressing data which would yield a different conclusion were it detected.

Ok, I agree with this. But let me elaborate. Though fair sampling is a necessary consideration in any experiment involving sampling, I've always more or less agreed with Bell's assessment (to paraphrase) that if, say, optical Bell tests involving the joint measurement of photons entangled in polarization were made loophole free, then there's every reason to believe that the results would more closely, not less closely, approximate qm predictions than loophole-ridden experiments do. Which is to say that the results would continue to violate BIs.

My concern has been that BI violations are taken by some to imply something about an underlying reality, and that this is sometimes portrayed as the 'mainstream' view. Which I don't think it is. That is, while it does seem pretty clearly demonstrated that Bell tests rule out a certain sort of 'local realistic' models of entanglement, it hasn't been (and really can't be) demonstrated that this is telling us anything about a reality underlying instrumental behavior.

I've been primarily concerned with why some people think that BI violations (or GHZ or Hardy 'theorems', etc.), or EPR deductions, inform us about some aspect(s) of a presumed 'reality' underlying entanglement correlations of the sort that prompt some people, such as jobsism, the OP of this thread, to ask how, wrt entangled 'particles', "the motion of one particle 'somehow' affects the other", and why these sorts of questions aren't just dismissed as being nonsensical -- with an accompanying, and hopefully concise, explanation of why they're nonsensical.

 

[ThomasT]

ThomasT has massive preconceived (or had depending on the day) notions about Bell, Aspect, EPR and more ...

If you're going to make statements like this, then I think you should be required to back them up. This is what I mean by vitriol, of a sort that might not be readily apparent, but nevertheless can undermine the credibility (whether that's the intent or not) of the person who it's aimed at. What I've been waiting, hoping, for you to do is to make some substantive comments regarding the questions that are being asked and the topics that are being discussed. Unless you do that, then I think you should just keep your opinions regarding other posters' credibilities to yourself.

Regarding Zonde's considerations, personally I think they're somewhat off-topic and if he wants to pursue them then he should start a different thread on it. Regarding his motivation(s) for his considerations, how can any of us pretend to know that? Regarding the validity of his arguments, well just deal with the arguments, straightforwardly, instead of all this circuitous , and yes, shadily vitriolic and disruptive stuff that you write.

Let's just have a nice discussion. Take whatever comes. Maybe we can all learn something. Unless you want to pretend that you know everything, then what's the problem with listening to somebody's concern and dealing with it in a straightforward manner?

Having said that, I agree with you that the OP has more than enough feedback to answer his/her question. Zonde can start a new thread on the fair sampling loophole if he wants to. And, after I reply to DA, who has had some interesting and substantive things to say wrt the topic of the thread, then that's it for me in this thread -- unless dx has some clarifications/corrections of my, possibly incorrect, replies to him, or whatever.