EPR Paradox Failure Explained for High Schoolers

[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.

 

[nismaratwork]

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.

Lets get this straight, saying that you have preconceptions IS NOT VITRIOL, and the evidence is in the thread started by Deepak Kapur. VITRIOL is: "Bitterly abusive feeling or expression." This, is, not, vitriol. I'm not undermining you either, as I've made quite the point that you are, however... um... reticently, willing to expand your horizons beyond those original preconceptions. It is meant to be a contrast of someone who is, and I don't mean this as an insult, very stubborn, with someone who is simply sessile in their beliefs and means of disseminating them (Zonde).

 

[ThomasT]

HUP is about the nature of the QM world.

I don't think it is. But we can agree to disagree on this.

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...)

The hup is interpreted, in the mainstream, as having to do with measurements. This is the de facto, mainstream, statistical interpretation of the hup. Whether or not it has anything to do with properties of or objects in an underlying reality is entirely a matter of inferential speculation. I suppose that you can get, logically, to some statement like "p and q can't have simultaneous reality", but that doesn't necessarily make it so. Such are the quandries associated with attempts to ascertain the physical meaning of the quantum theory. For all we (can) know, qm is just a fancy probability theory.

Models of certain aspects of reality, certain observed phenomena, do seem to be somewhat constrained. But whether those constraints are due to the makeup of reality or due to our ignorance thereof is unknown.

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.

So I guess we agree about this, but maybe there's a better way to phrase it. I don't know.

Regarding EPR 'elements of reality'. I agree with dx. It's quite ambiguous. Suffice it to say that we don't need entanglement to infer the existence of elements of reality. Any detection event will do.

Anyway, I'm reading over your 'hypotheses and corollaries'. Maybe I missed something. I'm known for that.

What I meant by ...

The explicit premise of Hidden Variable interpretations is value definiteness:

... not being quite correct is just that not all local realistic models depend on value definiteness in the way that BIs and GHZ require. These are the sorts of local realistic models of entanglement that quantify the situation in terms of a relationship between the entangled particles and the relationship between that relationship and the angular difference between the polarizers (regarding optical biphoton tests). In this way of looking at it the variables that determine individual detection are somewhat different than the variables determining joint detection.

But are there other local realistic models?

You can refer back to the very long thread. Of course none of these sorts of 'local realistic' models will pass DrC's 'test'. But keep in mind that DrC's test has only to do with Bell-type formulations based on his conception of the meaning of EPR 'elements of reality'. Also keep in mind that no viable theory can pass DrC's test. The problem of course is that it isn't really a test of local realism in the broadest sense of the term. It's a test that's based on the assumption that prospective detection attributes are in one to one correspondence with the properties of objects in an underlying reality. An unwarranted assumption, imho, and not in keeping with EPR at all.

And yes, of course there are other purported local realistic formulations that are experimentally viable and agree with qm predictions. Are they mainstream? No. Are they truly local and/or realistic? Well, it's a matter of contention. You can look at them and decide for youself. Do I believe that they're local realistic models? Well, maybe not.

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'.

I don't understand. What consistency trouble? Either the above statement of the hup (however simplistic) is correct or it's incorrect. Either way it involves accumulations of definite detection attributes.

 

[ThomasT]

Lets get this straight, saying that you have preconceptions IS NOT VITRIOL, and the evidence is in the thread started by Deepak Kapur.

It's shady, sneaky vitriol. And, since you said it, I want you to back it up with quotes -- or retract it.

 

[nismaratwork]

It's shady, sneaky vitriol. And, since you said it, I want you to back it up with quotes -- or retract it.

I will if a staff member gives me the green light, otherwise as I understand it blending two separate threads is verboten. Even then, I can assure that there is little emotional content in what I'm saying, and certainly nothing vitriolic. Anyone here can go to the thread in question and read more than select quotes I choose, and draw their own conclusions.

To be honest, I'm still not sure what you're objection is, because calling someone stubborn is hardly vitriol; you can't just massage and warp the language to suit your purposes. The word vitriol means what it means... I'd say that if you wish to continue to characterize what I've said as vitriolic, you should find a source that agrees with that, or retract your statement. There's a thread full of you running in circles with Dr. C and others... there's no dictionary on Earth that's going to agree with your definition of vitriol. In that context, you've accused me of being bitter and abusive... so prove it, or retract what is in essence, an insult.

 

[ThomasT]

I will if a staff member gives me the green light, otherwise as I understand it blending two separate threads is verboten.

You're the one who brought up the other thread in the first place, aren't you?

Even then, I can assure that there is little emotional content in what I'm saying, and certainly nothing vitriolic. Anyone here can go to the thread in question and read more than select quotes I choose, and draw their own conclusions.

What quotes??

There's a thread full of you running in circles with Dr. C and others... there's no dictionary on Earth that's going to agree with your definition of vitriol. In that context, you've accused me of being bitter and abusive... so prove it, or retract what is in essence, an insult.

Your posts are, generally, unnecessarily disruptive and off-topic. They don't add anything helpful to the discussions. They create bad feelings. And I happen to know that you've had similar problems in other threads. Now, as I've asked you before, do you want to discuss the topics at hand, or just go on and on with this silliness? If you don't have anything to say wrt the topic of the thread, then just don't say anything.

 

[zonde]

Why do you keep it going?

Because you are trying to ban the topic from discussions?
If you don't like it you can ignore it.

The above says it all: however unlikely... it is possible... And so are leprechauns. No evidence for them either.

So instead of giving your own argument you are questioning mine.
And for you "it is possible"="question closed and should be banned from discussions".
But then we are not talking in the same language. Only question is then in what language is Weihs talking.

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.

Interesting, and how does Rowe's et al experiment justify application of fair sampling assumption to photon detections?
Because if you do it you get ion entanglement? But in that case I don't understand why in photon polarization experiments photons are entangled but atoms are classical and can not be entangled but in ion experiment atoms are entangled but photons are classical and can not be entangled.
Does it depend in what way we intend to interpret results of experiment?

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.

Can you give reference to prediction and explain why it can be considered falsifiable?
Please understand that I am not talking about cataloguing empirical facts but about predictions.

 

[nismaratwork]

You're the one who brought up the other thread in the first place, aren't you?

What quotes??

Your posts are, generally, unnecessarily disruptive and off-topic. They don't add anything helpful to the discussions. They create bad feelings. And I happen to know that you've had similar problems in other threads. Now, as I've asked you before, do you want to discuss the topics at hand, or just go on and on with this silliness? If you don't have anything to say wrt the topic of the thread, then just don't say anything.

So that's a "no" to the whole vitriol issue?

Zonde: Dr. C, or me or anyone else doesn't have to make a novel argument to challenge your fringe idea! Fair sampling is ASSUMED, so you're the one who needs to present evidence to the contrary, which you have been unable to do. You're doing what you always do, and retreat into rhetorical circles... instead, how about you present that evidence which meets PF guidelines to support your ATM view?

EPR fails, because of Bell Inequalities... something that can be said here because fair sampling is the widely and generally accepted view. If you wish to present something else, maybe this isn't the place for you. Certainly the issue of whether or not EPR fails at all is central to the OP, and you're angry because no one is willing to go off on a tangent with you?... come on. You're just attacking Dr. C now, when you should be providing evidence to support your position.

 

[DevilsAvocado]

HUP is about the nature of the QM world.

I don't think it is. But we can agree to disagree on this.

Hum... you are not disagreeing with me, you are disagreeing with mainstream science.

The hup is interpreted, in the mainstream, as having to do with measurements.

Wrong.

http://en.wikipedia.org/wiki/Uncertainty_principle"
...
Published by Werner Heisenberg in 1927, the principle means that it is impossible to determine simultaneously both the position and momentum of an electron or any other particle with any great degree of accuracy or certainty. Moreover, his principle is not a statement about the limitations of a researcher's ability to measure particular quantities of a system, but it is a statement about the nature of the system itself as described by the equations of quantum mechanics.

Whether or not it has anything to do with properties of or objects in an underlying reality is entirely a matter of inferential speculation. I suppose that you can get, logically, to some statement like "p and q can't have simultaneous reality", but that doesn't necessarily make it so. Such are the quandries associated with attempts to ascertain the physical meaning of the quantum theory.

It would be great if you could end statements like this with; "but this is just my personal wishing & thinking, mainstream science has a completely different view." I think you are mixing up philosophy and physics.

http://en.wikipedia.org/wiki/Scientific_theory"

In the sciences, a scientific theory comprises a collection of concepts, including abstractions of observable phenomena expressed as quantifiable properties, together with rules (called scientific laws) that express relationships between observations of such concepts. A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as a principle or body of principles for explaining a class of phenomena.[1]

A scientific theory is a type of deductive theory, in that its content (i.e. empirical data) could be expressed within some formal system of logic whose elementary rules (i.e. scientific laws) are taken as axioms. In a deductive theory, any sentence which is a logical consequence of one or more of the axioms is also a sentence of that theory.[2]

In the humanities, one finds theories whose subject matter does not (only) concern empirical data, but rather ideas. Such theories are in the realm of philosophical theories as contrasted with scientific theories. A philosophical theory is not necessarily scientifically testable through experiment.

For example I can claim that Einstein was wrong: We can’t know if there is an luminiferous aether or not, it’s entirely a matter of inferential speculation. Relativity doesn’t say anything about the true nature of space!

This statement is scientifically obsolete, unless I have something more substantial than "philosophical speculations".

Sure, there are different interpretations of QM, however according to SEP this is the 'minimal' interpretation:

http://plato.stanford.edu/entries/qt-uncertainty/#MinInt"
...
Here we only describe a point of view, which we call the ‘minimal interpretation’, that seems to be shared by both the adherents of the Copenhagen interpretation and of other views.

In quantum mechanics a system is supposed to be described by its quantum state, also called its state vector. Given the state vector, one can derive probability distributions for all the physical quantities pertaining to the system such as its position, momentum, angular momentum, energy, etc. The operational meaning of these probability distributions is that they correspond to the distribution of the values obtained for these quantities in a long series of repetitions of the measurement. More precisely, one imagines a great number of copies of the system under consideration, all prepared in the same way. On each copy the momentum, say, is measured. Generally, the outcomes of these measurements differ and a distribution of outcomes is obtained. The theoretical momentum distribution derived from the quantum state is supposed to coincide with the hypothetical distribution of outcomes obtained in an infinite series of repetitions of the momentum measurement. The same holds, mutatis mutandis, for all the other physical quantities pertaining to the system. Note that no simultaneous measurements of two or more quantities are required in defining the operational meaning of the probability distributions.

As you can see, this is not solely a question about "simultaneous p and q", but the fundamental nature of the QM world.

As ZapperZ explains on his blog http://physicsandphysicists.blogspot.com/2006/11/misconception-of-heisenberg-uncertainty.html" :

While classical mechanics does not prohibit us from making as accurate of a prediction as we want, QM does! It is this predictive ability that is contained in the HUP. It is an intrinsic part of the QM formulation and not just simply a "measurement" uncertainty, as often misunderstood by many.

Zz.

And if you suspect there something 'wrong' in his rezoning, here’s physical proof of what Zz is talking about:

http://en.wikipedia.org/wiki/Walter_Lewin" (MIT) – The Heisenberg Uncertainty Principle

https://www.youtube.com/watch?v=<object width="640" height="505">
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</object>

(Personally I can’t see how you can reject the fact above? New "loopholes" or "unfair sampling" or what...??)

For all we (can) know, qm is just a fancy probability theory.

Wow! Just a fancy probability theory!? Well...

Have you considered what this "fancy probability theory" has brought to you?? I guess you have a computer, ISP, cell phone, TV, DVD player, CD player, MP3 player, digital camera, etc, etc? An estimated 30 percent of the U.S. gross national product is based on inventions made possible by quantum mechanics. That’s pretty impressive for "just a fancy probability theory", right?

I don't understand. What consistency trouble?

When I say "consistency trouble" I mean that we cannot "pick & choose" what fits our personal taste of QM, without getting into trouble in other parts of the scientific framework. HUP has been a fundamental part of QM since 1927. If you "change" the meaning of HUP, it will of course have consequences.

Let’s start with "nothing"; Zero-point energy is the lowest possible energy that a quantum mechanical physical system may have and it is the energy of its ground state. All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero-point energy, a consequence of the Heisenberg uncertainty principle. It was developed by Max Planck, Albert Einstein and Otto Stern. Zero-point energy is non-zero, due to HUP.

This is in turn important for http://en.wikipedia.org/wiki/Virtual_particle" , such as electric or magnetic fields, that exist without excitations that result in the carrying of information from place to place.

And then we can continue with http://en.wikipedia.org/wiki/Quantum_fluctuations" .

The concept of virtual particles infers http://en.wikipedia.org/wiki/Vacuum_energy" on cosmological scales.

Now you might say – Bahh! Virtual particles and vacuum energy doesn’t impress me. This is just talk!

Well it isn’t. The http://en.wikipedia.org/wiki/Casimir_effect" was proposed and formulated an in 1948, to show that the plates do affect the virtual photons which constitute the field, and generate a net force:

And in 1998 the Casimir effect was measured accurately:

http://arxiv.org/abs/physics/9805038"

Precision Measurement of the Casimir Force from 0.1 to 0.9 microns
Authors: U. Mohideen, Anushree Roy

(Submitted on 29 May 1998 (v1), last revised 9 Dec 1998 (this version, v2))
Journal reference: Phys.Rev.Lett.81:4549-4552,1998

Abstract: We have used an atomic force microscope to make precision measurements of the Casimir force between a metallized sphere of diameter 196 microns and flat plate. The force was measured for plate-sphere separations from 0.1 to 0.9 microns. The experimental results are consistent with present theoretical calculations including the finite conductivity, roughness, and temperature corrections. The root mean square average deviation of 1.6 pN between theory and experiment corresponds to a 1% deviation at the smallest separation.

This is just a few examples, and I can go on with the shapes of http://en.wikipedia.org/wiki/Electron_cloud" , etc, etc - but I think this says it all.

If you remove the "HUP brick" in the "house of QM", and make something else of it – the whole house falls apart.

If you want to challenge HUP, you better bring "the full house" – not one 'tasty' personal speculation.

Your personal speculation doesn’t work, because QM is built on http://en.wikipedia.org/wiki/Probability_distribution" , and HUP is at the base of this fundament:

 

[ThomasT]

Hum... you are not disagreeing with me, you are disagreeing with mainstream science.

DA, great post. I knew right after I said that I disagreed that the hup is about the nature of the quantum world that I should have qualified what I meant. I was assuming that by the quantum world you were referring to some reality underlying instrumental behavior. I'm just taking the quantum world to mean quantum experimental preparations, quantum experimental phenomena, and the formalism of the theory. If we agree on that, then of course I agree that the hup is about the nature of the quantum world.

 

[DevilsAvocado]

Thanks!

Well... maybe we are sliding into the measurement problem...

But, let’s formulate it like this: In the framework which QM uses to make predictions about the physical world, HUP is about indeterministic probabilities.

Okay?

Note: Personally I don’t think that the scientific evolution ends with QM in 2010. Of course there will be new theories, which most probably will discover completely new facts about the world. But today QM is, without competition, the most precise theory we have.

 

[DrChinese]

...how does Rowe's et al experiment justify application of fair sampling assumption to photon detections?
Because if you do it you get ion entanglement? But in that case I don't understand why in photon polarization experiments photons are entangled but atoms are classical and can not be entangled but in ion experiment atoms are entangled but photons are classical and can not be entangled.
Does it depend in what way we intend to interpret results of experiment?

1. Once you know fair sampling assumption is explicitly tested and supported, it can be extended elsewhere to similar tests. So we know that unfair sampling cannot be the cause of Bell test results.

2. Atoms are not classical and can be entangled.

 

[nismaratwork]

1. Once you know fair sampling assumption is explicitly tested and supported, it can be extended elsewhere to similar tests. So we know that unfair sampling cannot be the cause of Bell test results.

2. Atoms are not classical and can be entangled.

Those are the essential basics... how appropriate that your's is post "101"!

 

[ueit]

Wikipedia – Uncertainty principle
...
Published by Werner Heisenberg in 1927, the principle means that it is impossible to determine simultaneously both the position and momentum of an electron or any other particle with any great degree of accuracy or certainty. Moreover, his principle is not a statement about the limitations of a researcher's ability to measure particular quantities of a system, but it is a statement about the nature of the system itself as described by the equations of quantum mechanics.

This is not the first time when a false statement appears on Wikipedia (which is, by the way, not the direct expression of mainstream science).

In his book, "The physical principles of the quantum theory", page 20, Werner Heisenberg writes:

This formulation makes it clear that the uncertainty relation does not refer to the past; if the velocity of the electron is at first known and the position then exactly mesured, the position for times previous to the measurement may be calculated. Then for these past times Delta p x Delta q is smaller than the usual limiting value, but this knowledge of the past is of a purely speculative character, since it can never (because of the unknown change in momentum caused by the position measurement) be used as an initial condition in any calculation of the future progress of the electron ant thus cannot be subjected to experimental verification. It is a matter of personal belief whether such a calculation concerning the past hystory of the electron can be ascribed any physical reality or not

Now, in my oppinion, the simple fact that a simultaneous position and momentum can be ascribed for the past is strong evidence in favour of their physical reality. Otherwise, this fact has no explanation other than a strange coincidence. On the other hand there is a good explanation for uncertainty as a consequence of the measurement.

 

[DrChinese]

This is not the first time when a false statement appears on Wikipedia (which is, by the way, not the direct expression of mainstream science).

...

Now, in my oppinion, the simple fact that a simultaneous position and momentum can be ascribed for the past is strong evidence in favour of their physical reality. Otherwise, this fact has no explanation other than a strange coincidence. On the other hand there is a good explanation for uncertainty as a consequence of the measurement.

Everything here is basically absurd. And that is being kind.

There is NO evidence whatsoever that there is a simultaneous position and momentum for any quantum object. You can make an extrapolation as Heisenberg suggested. I can also multiply any value by any other value. So what is the physical meaning of such? Answer: none, in both cases.

As to Wikipedia, everything you say about that is wrong too. As per usual. If I wanted to get a summary of mainstream science in any area, Wikipedia would be one of my first sources. There is no better "direct expression of mainstream science" that I am aware of.

 

[DevilsAvocado]

This is not the first time when a false statement appears on Wikipedia

You have to explain why both Wikipedia & http://plato.stanford.edu/" are false.

http://plato.stanford.edu/entries/qt-uncertainty/#MinInt"
...
The same holds, mutatis mutandis, for all the other physical quantities pertaining to the system. Note that no simultaneous measurements of two or more quantities are required in defining the operational meaning of the probability distributions.

(which is, by the way, not the direct expression of mainstream science)

Okay, can you please tell us what the direct expression of mainstream science is? Don’t forget references.

Now, in my oppinion, the simple fact that a simultaneous position and momentum can be ascribed for the past is strong evidence in favour of their physical reality.

Well, that just your personal speculation, right?

My personal speculation is that physics is about making mathematical models and predictions about nature, and verify these predictions in physical experiments. If you are about to construct a CD player, using the knowledge of physics, you probably want to know in advance if the construction is working, theoretically. Not execute trial & error for a hundred years, to finally confirm that the last version worked, in retrospect...


@DrC: Agree.