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

[billschnieder]

Most of those are the same authors, and only a few are peer reviewed. The only one I think worth reading is the De Raedt, and that is simply because it is a computer model. If you study it, you will realize how difficult the modeling issue really is. Bell is respected with it - the only one of the lot I believe. Which is to say that their model does not claim to match QM.

Huh?

Shuang Zhao · Hans De Raedt · Kristel Michielsen
"Event-by-Event Simulation of Einstein-Podolsky-Rosen-Bohm Experiment"
Found Phys (2008) 38: 322–347
http://arxiv.org/abs/0712.3693

Abstract:
We construct an event-based computer simulation model of the Einstein-Podolsky-Rosen-Bohm experiments with photons. The algorithm is a one-to-one copy of the data gathering and analysis procedures used in real laboratory experiments. We consider two types of experiments, those with a source emitting photons with opposite but otherwise unpredictable polarization and those with a source emitting photons with fixed polarization. In the simulation, the choice of the direction of polarization measurement for each detection event is arbitrary. We use three different procedures to identify pairs of photons and compute the frequency of coincidences by analyzing experimental data and simulation data. The model strictly satisfies Einstein's criteria of local causality, does not rely on any concept of quantum theory and reproduces the results of quantum theory for both types of experiments. We give a rigorous proof that the probabilistic description of the simulation model yields the quantum theoretical expressions for the single- and two-particle expectation values.

H. De Raedt, K. De Raedt, K. Michielsen, K. Keimpema, S. Miyagarbagea
J. Comp. Theor. Nanosci. 4, 957 - 991, (2007)
"Event-by-event simulation of quantum phenomena: Application to Einstein-Podolosky-Rosen-Bohm experiments"
http://arxiv.org/abs/0712.3781

We review the data gathering and analysis procedure used in real Einstein-Podolsky-Rosen-Bohm experiments with photons and we illustrate the procedure by analyzing experimental data. Based on this analysis, we construct event-based computer simulation models in which every essential element in the experiment has a counterpart. The data is analyzed by counting single-particle events and two-particle coincidences, using the same procedure as in experiments. The simulation models strictly satisfy Einstein's criteria of local causality, do not rely on any concept of quantum theory or probability theory, and reproduce all results of quantum theory for a quantum system of two $S=1/2$ particles. We present a rigorous analytical treatment of these models and show that they may yield results that are in exact agreement with quantum theory. The apparent conflict with the folklore on Bell's theorem, stating that such models are not supposed to exist, is resolved. Finally, starting from the principles of probable inference, we derive the probability distributions of quantum theory of the Einstein-Podolsky-Rosen-Bohm experiment without invoking concepts of quantum theory.

K. Michielsen, S. Yuan, S. Zhao, F. Jin, H. De Raedt
"Coexistence of full which-path information and interference in Wheelers delayed choice experiment with photons"
Physica E, Volume 42, Issue 3, January 2010, Pages 348-353
http://arxiv.org/abs/0908.1032

We present a computer simulation model that is a one-to-one copy of an experimental realization of Wheeler's delayed-choice experiment that employs a single photon source and a Mach–Zehnder interferometer composed of a 50/50 input beam splitter and a variable output beam splitter with adjustable reflection coefficient R [V. Jacques, E. Wu, F. Grosshans, F. Treussart, P. Grangier, A. Aspect, J.-F. Roch, Phys. Rev. Lett. 100 (2008) 220402]. For 0<=R<=0.5, experimentally measured values of the interference visibility V and the path distinguishability D, a parameter quantifying the which-path information (WPI), are found to fulfill the complementary relation V2+D2less-than-or-equals, slant1, thereby allowing to obtain partial WPI while keeping interference with limited visibility. The simulation model that is solely based on experimental facts that satisfies Einstein's criterion of local causality and that does not rely on any concept of quantum theory or of probability theory, reproduces quantitatively the averages calculated from quantum theory. Our results prove that it is possible to give a particle-only description of the experiment, that one can have full WPI even if D=0, V=1 and therefore that the relation V^2+D^2<=1 cannot be regarded as quantifying the notion of complementarity.

Extended Boole-Bell inequalities applicable to quantum theory
Authors: Hans De Raedt, Karl Hess, Kristel Michielsen
http://arxiv.org/abs/0901.2546
In conclusion:

We have shown in a series of papers42,43,47,48,59 that it is possible to construct models, that is algorithms, that are locally causal in Einstein’s sense, generate the data set Eq. (126) and reproduce exactly the correlation that is characteristic for a quantum system in the singlet state. These algorithms can be viewed as concrete realizations of Fine’s synchronization model8. According to Bell’s theorem, such models do not exist. This apparent paradox is resolved by the work presented in this paper: There exists no Bell inequality for triples of pairs, there are only EBBI for pairs extracted from triples.
...
The central result of this paper is that the necessary conditions and the proof of the inequalities of Boole for n-tuples of two-valued data (see Section II) can be generalized to real non negative functions of two-valued variables (see Section III) and to quantum theory of two-valued dynamical variables (see Section IV). The resulting inequalities, that we refer to as extended Boole-Bell inequalities (EBBI) for reasons explained in the Introduction and in Section III, have the same form as those of Boole and Bell. Equally central is the fact that
these EBBI express arithmetic relations between numbers that can never be violated by a mathematically correct treatment of the problem: These inequalities derive from the rules of arithmetic and the non negativity of some functions only. A violation of these inequalities is at odds with the commonly
accepted rules of arithmetic or, in the case of quantum theory, with the commonly accepted postulates of quantum theory.
...
A violation of the EBBI cannot be attributed to influences at a distance. The only possible way that a viola-
tion could arise is if grouping is performed in pairs (see Section VII A).

I will just assume that you did not know what you were talking about. And in case you forgot, you still have not addressed a single point of my argument.

 

[DevilsAvocado]

Wooden mechanical horse simulator during WWI.

 

[RUTA]

billschnieder,

I read

Shuang Zhao · Hans De Raedt · Kristel Michielsen
"Event-by-Event Simulation of Einstein-Podolsky-Rosen-Bohm Experiment"
Found Phys (2008) 38: 322–347
http://arxiv.org/abs/0712.3693

I did not spend the hrs it would take me to reproduce all the calculations, so maybe I'm missing something. If so, hopefully you can correct me. Here is what I understand from the paper:

1. Given the manner by which experiments X and Y were carried out and the data analyzed, one cannot rule out local realism (LR).

2. They prove this by constructing an LR simulator which produces data that, when analyzed per the techniques of X and Y, violates Bell's inequality, i.e., gives |S| > 2.

3. They have NOT shown that it is possible to obtain |S| > 2 with an LR model in theory. What they HAVE shown is that it's impossible to rule out an LR model in experiments X and Y which found |S| > 2.

 

[billschnieder]

billschnieder,

I read

Shuang Zhao · Hans De Raedt · Kristel Michielsen
"Event-by-Event Simulation of Einstein-Podolsky-Rosen-Bohm Experiment"
Found Phys (2008) 38: 322–347
http://arxiv.org/abs/0712.3693

I did not spend the hrs it would take me to reproduce all the calculations, so maybe I'm missing something. If so, hopefully you can correct me. Here is what I understand from the paper:

1. Given the manner by which experiments X and Y were carried out and the data analyzed, one cannot rule out local realism (LR).

2. They prove this by constructing an LR simulator which produces data that, when analyzed per the techniques of X and Y, violates Bell's inequality, i.e., gives |S| > 2.

3. They have NOT shown that it is possible to obtain |S| > 2 with an LR model in theory. What they HAVE shown is that it's impossible to rule out an LR model in experiments X and Y which found |S| > 2.

1) and 2) You are correct. In that paper you referred to, they constructed a LR model which violates Bell inequality and agrees with QM.

3) Not quite. In the last I pointed to, they have shown that for purely mathematical reasons, it is not possible to apply Bell-type inequalities to the original EPRB type experiments where only pairs of data are recorded. They have shown by extending the thought experiment such that triples can be measured, and demonstrated that the inequalities are never violated even by QM.

They conclude (page 29):

In the original EPRB though experiment, one can measure pairs of data only, making de-facto impossible to use Boole's inequalities properly. This obstacle is remove in the extended EPRB though experiment discussed in Section VIC. In this extended EPRB experiment, one can measure both pairs and triples and consequantly, it is impossible for the data to violate Boole's inequalities. This statement is generally true: It does not depend on whether the internal dynamics of the apparatuses induces some correlations among different triples or that there are influences at a distance. The fact that this experiment yields triples of two-valued numbers is sufficient to guarantee that Boole's inequalities cannot be violated

The rigorous quantum theoretical treatment of a quantum flux tunneling problem (see Section V) and the EPRB experiment (see Section VI) provide explicit examples that quantum theory can never give rise to violations of the extended boole-bell inequalities

 

[DevilsAvocado]

I did not spend the hrs it would take me to reproduce all the calculations, so maybe I'm missing something.

I think what you may have missed is that Mr. BS is a very big fan of Crackpot Kracklauer:

And he will say and do anything to deceive you there is a real functional LR model. At least ThomasT has the decency to give you a hint ...

calling them LR models is a bit of a stretch

... on what this is all about ...

3. They have NOT shown that it is possible to obtain |S| > 2 with an LR model in theory. What they HAVE shown is that it's impossible to rule out an LR model in experiments X and Y which found |S| > 2.

Absolutely correct. As we all know – this is a computer simulation, nothing more nothing less. And I must say they use very "fancy" words:

Abstract:
We construct an event-based computer simulation model of the Einstein-Podolsky-Rosen-Bohm experiments with photons. The algorithm is a one-to-one copy of the data gathering and analysis procedures used in real laboratory experiments.

I don’t know about the algorithm in the paper, but the algorithm in the actual computer program is NOT "a one-to-one copy of the data gathering and analysis procedures used in real laboratory experiments".

There is actually one little line of code that does all the "magic":

There is absolutely no real "time window", only a pseudo-random number in r0, and this has nothing to do with real experiments – it’s just a case of trial & error and fine-tuning.

Don’t waste your time looking for a real LR model in this computer simulation – you never going to find it.

 

[RUTA]

1) and 2) You are correct. In that paper you referred to, they constructed a LR model which violates Bell inequality and agrees with QM.

3) Not quite. In the last I pointed to, they have shown that for purely mathematical reasons, it is not possible to apply Bell-type inequalities to the original EPRB type experiments where only pairs of data are recorded. They have shown by extending the thought experiment such that triples can be measured, and demonstrated that the inequalities are never violated even by QM.

Let's keep the conversation focused on Found Phys (2008) 38: 322–347. We can discuss the last paper later. Is this correct:

They have NOT shown that it is possible to obtain |S| > 2 with an LR model in theory. What they HAVE shown is that it's impossible to rule out an LR model in experiments X and Y which found |S| > 2.

 

[nismaratwork]

Let's keep the conversation focused on Found Phys (2008) 38: 322–347. We can discuss the last paper later. Is this correct:

They have NOT shown that it is possible to obtain |S| > 2 with an LR model in theory. What they HAVE shown is that it's impossible to rule out an LR model in experiments X and Y which found |S| > 2.

That is a beautiful example of rendering nearly a page of bluster down to a single coherent principle. As a reader of this thread, I thank you.

 

[RUTA]

Don’t waste your time looking for a real LR model in this computer simulation – you never going to find it.

I doubt they have an LR model that yields |S| > 2. If someone had managed to create such a model, it would've sent at very least a ripple though the foundations community and I haven't heard anything about it. I've only read the 2008 FoP paper, so I can only comment on that paper at this time.

In that paper they don't claim to have an LR model that yields |S| > 2. You have to read the paper very carefully so as not to misinterpret their statements. What they DO have is an LR model that generates data which, when subjected to data analysis per a couple of legit EPR-Bell experiments, yields |S| > 2. So, what can you conclude from this? Well, you CANNOT conclude that LR models can violate Bell's inequality. Only that LR models can APPEAR to violate Bell's inequality under certain experimental conditions.

If in fact their calculations are correct (again, I didn't check them, but they were published so I'm willing to give the referees and editor of FoP some credit), I think their work is very good physics and deserved to be published. Their conclusion, while not the "LR savior" anti-EPR advocates are looking for, is not insignificant. I'm going to speculate, hoping someone can correct me if I'm way off (I may be).

The "loop hole" they found has to do with the fact that there is a low coincidence frequency, i.e., the experiment has hundreds of thousands of events but only about 13,000 coincidences. Superficially, of course, that means your LR model need only yield |S| > 2 for the "right" 13,000-element subset of its data. Anyone disagree?

I actually think their work is "cool" and I'm glad someone is doing this dirty "police" work. If I had refereed this paper and found all the calculations to be correct, I would've recommended publication. I think this kind of work is important.

 

[DevilsAvocado]

I doubt they have an LR model that yields |S| > 2. If someone had managed to create such a model, it would've sent at very least a ripple though the foundations community and I haven't heard anything about it. I've only read the 2008 FoP paper, so I can only comment on that paper at this time.

Yeah, and why not a front page in Nature or Scientific American!?

In that paper they don't claim to have an LR model that yields |S| > 2.

This is something Mr. BS must have missed...!? ()

You have to read the paper very carefully so as not to misinterpret their statements. What they DO have is an LR model that generates data which, when subjected to data analysis per a couple of legit EPR-Bell experiments, yields |S| > 2. So, what can you conclude from this? Well, you CANNOT conclude that LR models can violate Bell's inequality. Only that LR models can APPEAR to violate Bell's inequality under certain experimental conditions.

Very interesting! I know DrC is working hard on this, and he made https://www.physicsforums.com/showpost.php?p=2724402&postcount=389" to analyze the data.

The "loop hole" they found has to do with the fact that there is a low coincidence frequency, i.e., the experiment has hundreds of thousands of events but only about 13,000 coincidences. Superficially, of course, that means your LR model need only yield |S| > 2 for the "right" 13,000-element subset of its data. Anyone disagree?

I can’t say for certain, but I know DrC is going to love to discuss this. As far as I understand, they are exploiting the "time window" in a way that the angle is 'responsible' for the amount of random "add-ons". But I can definitely be wrong. We have to wait for DrC.

I actually think their work is "cool" and I'm glad someone is doing this dirty "police" work. If I had refereed this paper and found all the calculations to be correct, I would've recommended publication. I think this kind of work is important.

Yes, it’s cool, but I don’t think it’s cool what Mr. BS is doing – claiming this is proof of a real LR model.

 

[RUTA]

Yes, it’s cool, but I don’t think it’s cool what Mr. BS is doing – claiming this is proof of a real LR model.

It's no proof of an LR model for Bell inequality violations. It's value resides in that it shows why a particular pair of experiments cannot rule out LR models. At least that's what I see.

 

[billschnieder]

They have NOT shown that it is possible to obtain |S| > 2 with an LR model in theory. What they HAVE shown is that it's impossible to rule out an LR model in experiments X and Y which found |S| > 2.

It is clear to me from their paper that
a) They have provided an "LR model" of the experiments under consideration. (Section V)
b) For the two types of experiments they considered, they showed that their model agrees with the QM prediction and violates Bell for some values of d. (Section IV)

Let us assume that we can analyze our simulation model, described in Section V, by
replacing the deterministic sequence of pseudo-random numbers by the mathematical con-
cept of independent random variables, as defined in the (Kolmogorov) theory of probabil-
ity [29, 30]. Under this assumption, each event constitutes a Bernouilli trial [29, 30] and we
can readily obtain analytical expressions for the expectation values that we compute with
the simulation model.
This section serves three purposes. First, it provides a rigorous proof that for up to first
order in W and for d = 4, the probabilistic description of the simulation model exactly
reproduces the single particle averages and the two-particle correlations of quantum theory
for the system under consideration. Second, it illustrates how the presence of the time-
window introduces correlations that cannot be described by the original Bell-like “hidden-
variable” models [14]. Third, it reveals a few hidden assumptions that are implicit in the
derivation of the specific, factorized form of the two-particle correlation that is essential to
Bell’s work.

The authors are not ambiguous about what they claim to have demonstrated. At least to me, it is clear that they have a LR model which violates Bell's inequalities but agrees with QM.

Summarizing: We have demonstrated that a simulation model that strictly satisfies Ein-
stein’s criteria of locality can reproduce, event-by-event, the quantum theoretical results for
EPRB experiments with photons, without using any concept from quantum theory. We
have given a rigorous proof that this model reproduces the single-particle expectations and
the two-particle correlation of two S = 1/2 particles in the singlet state and product state.

If you do not think they have presented an LR model which agrees with QM and disagrees with Bell for the two types of experiments they considered, you will have to clarify what you mean by
1) LR Model
2) obtain |S| > 2 in theory

 

[DevilsAvocado]

OMG, here we go again. Perception and logic at the level of a 10-yearold, now we can "look forward" to >100 posts on this...

 

[JesseM]

It is clear to me from their paper that
a) They have provided an "LR model" of the experiments under consideration. (Section V)
b) For the two types of experiments they considered, they showed that their model agrees with the QM prediction and violates Bell for some values of d. (Section IV)

The two types of experiments they considered are ones that contain experimental loopholes. They do not show in that paper that a LR model could violate Bell inequalities even in a loophole-free experiment that satisfied all the experimental conditions assumed by Bell. Note on p. 4 where they say:

The crucial
point of the present and of our earlier work [15, 21, 22, 23] is that we simulate a model of
the real EPRB experiments, not of the simplified, gedanken-type version that is commonly
used [17, 18, 19].

Also note that DrChinese did a detailed analysis of the De Raedt model on this thread, and concluded in post #47:

I have been working with the De Raedt team for several months to address the issue identified in this thread. Thanks especially to Dr. Kristel Michielsen for substantial time and effort to work with me on this.

The issue I identified was rectified very quickly using what they call their "Model 2" algorithm. My earlier analysis was using their older "Model 1" algorithm. After getting to the point where we were able to compare statistics for a jointly agreed upon group of settings, I am satisfied that they have a simulation which accomplishes - in essence - what they claim.

...

Please keep in mind that the De Raedt model is a computer simulation which exploits the coincidence time window as a means to achieve a very interesting result: It is local realistic. Therefore, it is able to provide event by event detail for 3 (or more) suimultaneous settings (i.e. it is realistic). It does this with an algorithm which is fully independent (i.e. local/separable). It does not violate a Bell Inequality for the full universe but does (somewhat) for the sample.

So, seems to be exploiting some variant of the detector efficiency loophole.

 

[billschnieder]

The two types of experiments they considered are ones that contain experimental loopholes. They do not show in that paper that a LR model could violate Bell inequalities even in a loophole-free experiment that satisfied all the experimental conditions assumed by Bell.

I take it you believe it is possible to perform an EPRB experiment which is 100% faithful to all of Bell's assumptions. For reasons I have already explained, I do not share that belief. The fact that no such experiment has ever been performed is definitely telling.

And since non-localists rely on the same "loopholed experiments" to proclaim the demise of locality, a locally causal explanation of those same experiments however "loopholed" they are, is an effective counter argument. So contrary to what you might think, the fact that the experiments so modeled, are not loophole free, is not a serious response to the model.

So, seems to be exploiting some variant of the detector efficiency loophole.

No. Read the paper! I should also say I simply enjoy your choice of words here: "exploiting .. loophole". When
Weihs et al. did their experiments and published the result, I did not hear non-localists clamouring that they "exploited ... loophole".

Also note that DrChinese did a detailed analysis of the De Raedt model on this thread, and concluded in post #47:

You mean the same DrChinese who said contrary to what the authors themselves explicitly claimed in the paper that:

The only one I think worth reading is the De Raedt,... Bell is respected with it - the only one of the lot I believe. Which is to say that their model does not claim to match QM.

 

[JesseM]

I take it you believe it is possible to perform an EPRB experiment which is 100% faithful to all of Bell's assumptions.

It would be possible (in principle) to perform an experiment 100% faithful to all his assumptions about the observable conditions of the experiment, yes. Of course the experiment need not match the theoretical assumptions about hidden variables, since the whole point would be to compare a real experiment which matches these observable experimental conditions to what LR hidden-variables theories would predict about an experiment which matches these observable experimental conditions.

And since theorists have come up with modified Bell inequalities that deal with imperfect detector efficiency, it's really only necessary to perform an experiment where the detector efficiency is above a certain threshold, it doesn't have to be perfect as assumed in the original Bell inequalities. As we've discussed before, there have been experiments that got the detector efficiency above such a threshold, although they didn't simultaneously close the locality loophole (and we've also discussed why I think it's very unlikely the true laws of physics would be a hidden-variable theory that exploits both loopholes simultaneously, and why I think it's likely that experiments closing both loopholes will be possible in the near future).

And since non-localists rely on the same "loopholed experiments" to proclaim the demise of locality, a locally causal explanation of those same experiments however "loopholed" they are, is an effective counter argument.

Not if the De Raedt model fails to simultaneously exploit the locality loophole (or it does but requires a very contrived and complicated algorithm).

So, seems to be exploiting some variant of the detector efficiency loophole.

No. Read the paper!

I'm trusting DrChinese's analysis, unless you can show where it's wrong--do you claim there is some section of the paper that demonstrates that every simulated photon emitted by the source is actually detected? If so, perhaps you could quote that section?

You mean the same DrChinese who said contrary to what the authors themselves explicitly claimed in the paper that:

The only one I think worth reading is the De Raedt,... Bell is respected with it - the only one of the lot I believe. Which is to say that their model does not claim to match QM.

Where do the authors "explicitly claim" otherwise? Keep in mind the context, DrChinese would presumably say here that a model which violates the Bell inequalities in experiments with loopholes but respects them in loophole-free experiments is still a model where "Bell is respected". So the fact that the authors may talk about how Bell inequalities are violated doesn't mean that they would disagree that "Bell is respected" in the sense which DrChinese meant that phrase.

 

[DevilsAvocado]

So, seems to be exploiting some variant of the detector efficiency loophole.

I can only tell about the version DrC made for Excel, which you can https://www.physicsforums.com/showpost.php?p=2724402&postcount=389", and I assume it’s their older "Model 1" algorithm.

The one and only 'thing' that can be responsible for the achieved result, is in what they call the "time window", and a pseudo-random number in r0 that is altered depending on the current angle:

I guess that only Mr. BS would call this a real LR model, explaining a real underlying theory in nature...

 

[billschnieder]

It would be possible (in principle) to perform an experiment 100% faithful to all his assumptions about the observable conditions of the experiment, yes.

I disagree that this is possible, as I explained in post #1076:
https://www.physicsforums.com/showpost.php?p=2804344&postcount=1076

And since theorists have come up with modified Bell inequalities that deal with imperfect detector efficiency ...

Completely irrelevant. The simulation model is not dealing with detection efficiency loophole. It deals with the coincidence time window, or if you prefer "coincidence time loophole".

Not if the De Raedt model fails to simultaneously exploit the locality loophole (or it does but requires a very contrived and complicated algorithm).

Huh? What are you talking about?

I'm trusting DrChinese's analysis, unless you can show where it's wrong--do you claim there is some section of the paper that demonstrates that every simulated photon emitted by the source is actually detected? If so, perhaps you could quote that section?

Again this doesn't make sense because De Raedt were modelling an actual experiment, so expecting them make their model so it deliberately does not correspond to what is actually done and observed in the real experiment is queer. If in a real experiment only 5% of photons are detected, and a model is presented for the experiment in which 100% of photons are detected, that will be grounds for invalidating the model. This is simple logic and how science is normally done.

We construct an event-based computer simulation model of the Einstein-Podolsky-Rosen-Bohm
experiments with photons. The algorithm is a one-to-one copy of the data gathering and analysis
procedures used in real laboratory experiments. We consider two types of experiments, those with a source emitting photons with opposite but otherwise unpredictable polarization and those with a source emitting photons with fixed polarization. In the simulation, the choice of the direction of polarization measurement for each detection event is arbitrary. We use three different procedures to identify pairs of photons and compute the frequency of coincidences by analyzing experimental data and simulation data. The model strictly satisfies Einstein’s criteria of local causality, does not rely on any concept of quantum theory and reproduces the results of quantum theory for both types of experiments. We give a rigorous proof that the probabilistic description of the simulation model yields the quantum theoretical expressions for the single- and two-particle expectation values.

Feel free to trust DrC's analysis. To me the simple fact that he misrepresents their explicitly stated claims is disqualifying.

You can swindle "Bell is respected with it ... Which is to say that their model does not claim to match QM" all you want. The authors' claims are pretty clear. Read the paper yourself and see if you still agree with DrC that their model does not claim to match QM.

Summarizing: We have demonstrated that a simulation model that strictly satisfies Ein-
stein’s criteria of locality can reproduce, event-by-event, the quantum theoretical results for
EPRB experiments with photons, without using any concept from quantum theory. We
have given a rigorous proof that this model reproduces the single-particle expectations and
the two-particle correlation of two S = 1/2 particles in the singlet state and product state.

 

[JesseM]

It would be possible (in principle) to perform an experiment 100% faithful to all his assumptions about the observable conditions of the experiment, yes. Of course the experiment need not match the theoretical assumptions about hidden variables, since the whole point would be to compare a real experiment which matches these observable experimental conditions to what LR hidden-variables theories would predict about an experiment which matches these observable experimental conditions.

I disagree that this is possible, as I explained in post #1076:
https://www.physicsforums.com/showpost.php?p=2804344&postcount=1076

Your argument there is based on a failure to distinguish "assumptions about the observable conditions of the experiment" from "theoretical assumptions about hidden variables"--this sort of confusion is common in your arguments, which is exactly why I phrased my comment in the way I did.

In a case like the Leggett-Garg inequality, the "observable conditions of the experiment" include the idea that on each trial we measure the system at two out of three possible times. Then an inequality is derived based on the theoretical assumption that the system has a well-defined state at all three times (and that the state isn't influenced by your measurements), even the time that we don't actually measure. So if you want to test the theoretical assumption, you do an experiment that matches the specified "observable conditions", and if you find the inequality is violated, that falsifies the theoretical assumption that each measured system had a well-defined state at all three times which wasn't influenced by the measurements.

You earlier showed that you understood the idea of my scratch lotto card example--in that example, each experimenter had a card with three possible boxes (for a total of six boxes), but the experiment only involved each scratching one box (a total of two boxes revealed). The theoretical assumption being tested was that there was an unchanging "hidden fruit" behind all six boxes, and the conclusion was that if experiments always found the same fruit on trials where both experimenters chose the same box, then on trials where both experimenters chose different boxes they should find the same fruit at least 1/3 of the time. If they perform this experiment many times (with perfect 'efficiency' so no cards have to be thrown out) and find that they only get the same fruit 1/4 of the time when they choose different boxes, isn't this a valid falsification of the hypothesis that there was an unchanging hidden fruit behind all six boxes? You wouldn't say the experiment failed to show anything because they assumed six variables with well-defined values but only sampled two, would you?

Completely irrelevant. The simulation model is not dealing with detection efficiency loophole. It deals with the coincidence time window, or if you prefer "coincidence time loophole".

Does the computer model assume every emitted photon is detected? If not, why are you so sure they aren't exploiting this loophole? Anyway, you may be right that they exploit the coincidence-time loophole, a slightly different experimental loophole I hadn't been thinking of (discussed here). I think you could view it as a type of detector efficiency loophole in any case, since it means that the detectors aren't correctly identifying all entangled pairs as pairs.

Not if the De Raedt model fails to simultaneously exploit the locality loophole (or it does but requires a very contrived and complicated algorithm).

Huh? What are you talking about?

I was responding to your statement 'since non-localists rely on the same "loopholed experiments" to proclaim the demise of locality, a locally causal explanation of those same experiments however "loopholed" they are, is an effective counter argument.' A model is not an "effective counter argument" if it can't actually explain all the different types of experimental results seen so far, including the experiments where the detector efficiency loophole was closed but the locality loophole was not.

I'm trusting DrChinese's analysis, unless you can show where it's wrong--do you claim there is some section of the paper that demonstrates that every simulated photon emitted by the source is actually detected? If so, perhaps you could quote that section?

Again this doesn't make sense because De Raedt were modelling an actual experiment, so expecting them make their model so it deliberately does not correspond to what is actually done and observed in the real experiment is queer.

I'm not "expecting them" to do anything different than what they did. I was responding to your comment "No. Read the paper!" in response to my comment "seems to be exploiting some variant of the detector efficiency loophole." If you were denying that they exploited the detector efficiency loophole, wouldn't that mean you were claiming that their model assumed conditions of perfectly efficient detection?

Feel free to trust DrC's analysis. To me the simple fact that he misrepresents their claims is disqualifying.

But he doesn't misrepresent their claims, his claim is perfectly correct if you understand what he means by "Bell is respected" (namely, that their model would obey Bell inequalities in an experimental setup that actually matched the observable experimental conditions assumed by Bell). If you're just saying that the claim "Bell is respected" would be wrong if we had a different interpretation of the meaning of that phrase, then you're just quibbling over DrChinese's choice of language, not saying his discussion is wrong in any more substantive sense.

 

[RUTA]

It is clear to me from their paper that
a) They have provided an "LR model" of the experiments under consideration. (Section V)
b) For the two types of experiments they considered, they showed that their model agrees with the QM prediction and violates Bell for some values of d. (Section IV)

The authors are not ambiguous about what they claim to have demonstrated. At least to me, it is clear that they have a LR model which violates Bell's inequalities but agrees with QM.

If you do not think they have presented an LR model which agrees with QM and disagrees with Bell for the two types of experiments they considered, you will have to clarify what you mean by
1) LR Model
2) obtain |S| > 2 in theory

I suspect we agree on what constitutes an LR model and that indeed they have an LR model. We should also agree that the data provided by their LR model yields |S| > 2 when subjected to the analysis in question. Where we might disagree is on whether or not they have an LR model that yields |S| > 2 in theory.

That is to say, their LR model can produce unambiguous pairs of events, so there is no need in theory to use the experimental procedure for finding correlated events -- they can easily program their data so that every pair of events is correlated (whereas only a tiny fraction of those under experimental analysis are correlated). Under this type of analysis their LR model will not produce |S| > 2.

So, again, they have not found an LR model that violates Bell's inequality. What they have found is a loop hole in these two particular experiments whereby an LR model can appear to violate Bell's inequality because of the analysis that must be used in a real experiment when you don't know which pairs of events are correlated. Again, this limitation is NOT applicable to their LR model because they CAN know which events are correlated in their model and, using this knowledge, they can easily show that their LR model doesn't violate Bell's inequality.

 

[billschnieder]

Your argument there is based on a failure to distinguish "assumptions about the observable conditions of the experiment" from "theoretical assumptions about hidden variables"--this sort of confusion is common in your arguments, which is exactly why I phrased my comment in the way I did.

My argument is broken down into points as follows:

1) Bell's inequalities can be derived from triples of dichotomous variables without any physical assumption
2) In Bell-test experiments only pairs of values are ever collected at a time (a dataset of pairs)
3) A dataset of pairs can be made to violate inequalities derived from a dataset of triples for purely mathematical reasons
4) I have provided mathematical proof of (1), (2) is an accepted fact. I have provided proof of (3) via simulation
5) Therefore, the violation of Bell's inequalities derived from triples, by experiments such as Bell-test experiments which only collect pairs, is not surprising, it is expected for purely mathematical reasons, having nothing to do with realism or locality.
6) Therefore, Bell's inequality can never be violated by a dataset of triples, even if the physical assumption of of spooky action at a distance is mandated!

If you are now seriously considering responding to it, please clearly point out which of the above points is wrong and why it is wrong. I could not discern a clear response against any of the above points in anything you have written.

Does the computer model assume every emitted photon is detected? If not, why are you so sure they aren't exploiting this loophole?

Had you read the paper, you will have understood this. They have a single parameter dwhich corresponds to the coincidence time window, and they clearly show that with values of d similar to what is used in real experiments, Bell is violated and the simulation agrees with QM but if no coincidence time window is introduced ie d = 0, which is NOT what is done in real experiments, the simulation respects Bell and disagrees with QM, even though not all photons are detected. So yeah, I am pretty sure that their simulation has nothing to do with detection efficiency, and you will be too if only you read the article.

A model is not an "effective counter argument" if it can't actually explain all the different types of experimental results seen so far, including the experiments where the detector efficiency loophole was closed but the locality loophole was not.

Again, despite your wishes, this model has nothing to do with detector efficiency.

his claim is perfectly correct if you understand what he means by "Bell is respected" (namely, that their model would obey Bell inequalities in an experimental setup that actually matched the observable experimental conditions assumed by Bell).

Exactly zero such experimental setups have been realized to date. They present a model of a real experimental setup and THEY CLAIM that their model agrees with QM as evidenced by their own words which I have quoted to you. You can disagree with their claims but you certainly can not say they claim the opposite to what they actually claim, by introducing some other setup, which has never been realized and which they never set out to model. Dr C is free to state that in his opinion, their model agrees with Bell and disagrees with QM. But to say their model does not claim to match QM is false. The former states an opinion about their model, the latter purports to represent their claims but does not. This is obvious, and no amount of quibbling can change this. So feel free to continue the quibbling but count me out of it.

 

[billschnieder]

I suspect we agree on what constitutes an LR model and that indeed they have an LR model. We should also agree that the data provided by their LR model yields |S| > 2 when subjected to the analysis in question. Where we might disagree is on whether or not they have an LR model that yields |S| > 2 in theory.

That is to say, their LR model can produce unambiguous pairs of events, so there is no need in theory to use the experimental procedure for finding correlated events -- they can easily program their data so that every pair of events is correlated (whereas only a tiny fraction of those under experimental analysis are correlated). Under this type of analysis their LR model will not produce |S| > 2.

So, again, they have not found an LR model that violates Bell's inequality.

Would you say the Weihs et al experiment violated Bell's inequality and agreed with QM, or would you say the Weihs et al experiment appeared to violate Bell's inequality because it exploited the coincidence time loophole? If you have no problem with this interpretation of the Weihs et all experiment, which they are modelling, I see not reason to expect anything different about their model.

What they have found is a loop hole in these two particular experiments whereby an LR model can appear to violate Bell's inequality because of the analysis that must be used in a real experiment when you don't know which pairs of events are correlated. Again, this limitation is NOT applicable to their LR model because they CAN know which events are correlated in their model and, using this knowledge, they can easily show that their LR model doesn't violate Bell's inequality.

Sure, you can say that. But they are modelling the experiment, and their model of the experiment violates Bell and agrees with QM. I think you would agree that d=0 does not correspond to the experiments they were modelling.

 

[RUTA]

Would you say the Weihs et al experiment violated Bell's inequality and agreed with QM, or would you say the Weihs et al experiment appeared to violate Bell's inequality because it exploited the coincidence time loophole? If you have no problem with this interpretation of the Weihs et all experiment, which they are modelling, I see not reason to expect anything different about their model.


Sure, you can say that. But they are modelling the experiment, and their model of the experiment violates Bell and agrees with QM. I think you would agree that d=0 does not correspond to the experiments they were modelling.

Nature is producing the experimental data and, unlike the LR model, we don't know how She's doing that. Thus, we say simply that Weil's experiment violated Bell's inequality and agreed with QM, just like we can (and I did) say the LR model violated Bell's inequality and agreed with QM (although, I had to add the qualifier -- "using the analysis of this experiment"). The reason for the qualifier is that we KNOW if the LR model is programmed to produce correlated pairs unambiguously, which it can do, then it will NOT violate Bell's inequality and NOT agree with QM.

I'm not trying to play semantic games, there is a distinction between the following two claims:

1. I have an LR model that produces data which when analyzed per experiment X violates Bell's inequality and agrees with QM.

2. I have an LR model that violates Bell's inequality and agrees with QM.

You have to choose your words carefully so as not to conflate these two claims.

 

[Gordon Watson]

Nature is producing the experimental data and, unlike the LR model, we don't know how She's doing that. Thus, we say simply that Weil's experiment violated Bell's inequality and agreed with QM, just like we can (and I did) say the LR model violated Bell's inequality and agreed with QM (although, I had to add the qualifier -- "using the analysis of this experiment"). The reason for the qualifier is that we KNOW if the LR model is programmed to produce correlated pairs unambiguously, which it can do, then it will NOT violate Bell's inequality and NOT agree with QM.

I'm not trying to play semantic games, there is a distinction between the following two claims:

1. I have an LR model that produces data which when analyzed per experiment X violates Bell's inequality and agrees with QM.

2. I have an LR model that violates Bell's inequality and agrees with QM.

You have to choose your words carefully so as not to conflate these two claims.

Dear RUTA,

Sorry, but (for me) this is NOT your clearest piece of writing (which I value). Could you take more words, please, to make your points more clearly and expansively?

They seem to be important; though I am sure to be in disagreement, even when they have been clarified.

PS: Could you explain, and elaborate fairly fully, why you capitalized KNOW here?

The reason for the qualifier is that we KNOW if the LR model is programmed to produce correlated pairs unambiguously, which it can do, then it will NOT violate Bell's inequality and NOT agree with QM.

What do we KNOW here, and how do we KNOW IT, please?

PPS: Please clear your PF mail box.

Thank you very much,

JenniT

 

[billschnieder]

I'm not trying to play semantic games, there is a distinction between the following two claims:

1. I have an LR model that produces data which when analyzed per experiment X violates Bell's inequality and agrees with QM.

2. I have an LR model that violates Bell's inequality and agrees with QM.

You have to choose your words carefully so as not to conflate these two claims.

I see your point. My point though is the following: Claim (1) and (2) are not different within the context of the paper we are discussing so I do not see why you insist on making a distinction. The authors did not claim to be deriving "an LR model" in a general sense. Their focus in that paper is to present "an LR model of the experiment" and in that context you can not separate their model from the constraints imposed by the experimental situation being modeled. It seems from your phrasing of (1) that you prefer to to do that. But do you apply the same standard to QM? QM only gives predictions for clearly stated experimental setups. I don't think you will expect QM to generate a dataset which you will then analyze according to experiment X.

 

[DevilsAvocado]

I'm not trying to play semantic games

Well, I’m afraid you’ll have to... Semantic games are Mr. BS favorite engagement. The more completely meaningless words he produces, the happier he gets. Just watch and learn...

 

[JesseM]

My argument is broken down into points as follows:

1) Bell's inequalities can be derived from triples of dichotomous variables without any physical assumption
2) In Bell-test experiments only pairs of values are ever collected at a time (a dataset of pairs)
3) A dataset of pairs can be made to violate inequalities derived from a dataset of triples for purely mathematical reasons
4) I have provided mathematical proof of (1), (2) is an accepted fact. I have provided proof of (3) via simulation
5) Therefore, the violation of Bell's inequalities derived from triples, by experiments such as Bell-test experiments which only collect pairs, is not surprising, it is expected for purely mathematical reasons, having nothing to do with realism or locality.
6) Therefore, Bell's inequality can never be violated by a dataset of triples, even if the physical assumption of of spooky action at a distance is mandated!

If you are now seriously considering responding to it, please clearly point out which of the above points is wrong and why it is wrong. I could not discern a clear response against any of the above points in anything you have written.

3) is ambiguous. It's true a dataset of pairs can be made to violate inequalities from a set of triples under certain sampling conditions, but not under the conditions assumed by Bell, where the choice of which two values to measure is random on each trial, and there is no correlation between the probability of a given triple and the choice of which pair to measure on a given trial.

Had you read the paper, you will have understood this. They have a single parameter dwhich corresponds to the coincidence time window, and they clearly show that with values of d similar to what is used in real experiments, Bell is violated and the simulation agrees with QM but if no coincidence time window is introduced ie d = 0, which is NOT what is done in real experiments, the simulation respects Bell and disagrees with QM, even though not all photons are detected. So yeah, I am pretty sure that their simulation has nothing to do with detection efficiency, and you will be too if only you read the article.

Suppose the simulation was altered so that 100% of all photons were detected by the simulated detectors--would the model continue to violate Bell inequalities? If not, I would say that by definition it is exploiting the detector efficiency loophole, even if it is also exploiting the coincidence time loophole.

his claim is perfectly correct if you understand what he means by "Bell is respected" (namely, that their model would obey Bell inequalities in an experimental setup that actually matched the observable experimental conditions assumed by Bell).

Exactly zero such experimental setups have been realized to date.

Do you think this is relevant to judging whether DrChinese's claim is correct or not? Bell's original proof did not concern any experiment, it was about comparing the theoretical predictions of local realism to the theoretical predictions of QM, and noting that their predictions must differ in certain theoretically-possible experimental setups. So, it's worth pointing out (as DrChinese did) that the model in the paper does not disprove Bell's theoretical claims, since it would obey the Bell inequalities in the theoretically-possible experimental setup Bell was discussing.

They present a model of a real experimental setup and THEY CLAIM that their model agrees with QM as evidenced by their own words which I have quoted to you.

They only claim that it agrees with QM for the specific experiments they analyze. I doubt they claim it would agree with QM in all the Aspect-type experiments that have been done to date, let alone in any experiment which is theoretically possible in QM

Dr C is free to state that in his opinion, their model agrees with Bell and disagrees with QM. But to say their model does not claim to match QM is false.

When he says it "disagrees with QM", I think he means that it would not make the same predictions as QM in all theoretically-possible experiments. Assuming that this is what he meant, then if your criticism is meant to be something more than a semantic quibble about the words he used to express this idea, do you think anything the authors said contradicts the claim that there model would not make the same predictions as QM in all theoretically-possible experiments?

 

[RUTA]

I see your point. My point though is the following: Claim (1) and (2) are not different within the context of the paper we are discussing so I do not see why you insist on making a distinction. The authors did not claim to be deriving "an LR model" in a general sense. Their focus in that paper is to present "an LR model of the experiment" and in that context you can not separate their model from the constraints imposed by the experimental situation being modeled. It seems from your phrasing of (1) that you prefer to to do that. But do you apply the same standard to QM? QM only gives predictions for clearly stated experimental setups. I don't think you will expect QM to generate a dataset which you will then analyze according to experiment X.

I'm not a good writer. In fact, I'm not a good communicator in general. Sorry, I'll try again. Keep in mind that I'm conveying my opinion about their work. If you know that my opinion is wrong, maybe you could explain that to me.

I like your phrase, "an LR model of the experiment." That's right on the money. Now, the experiment is also in agreement with QM. Does that mean the LR model and QM are equivalent? No. What's the difference between QM and the LR model? If you wrote a computer program to simulate a perfect set of QM data, i.e., no guess work as to which pairs of events are correlated, then it would give |S| > 2. If you do the same with the LR model, it will not give |S| > 2.

Therefore, what the LR model shows is that you cannot use this experiment to claim, "We have proof that QM's prediction of |S| > 2 is right," because a computer simulator (their LR model) which doesn't give |S| > 2 does create data which give |S| > 2 when analyzed via this experiment.

How's that?

 

[DevilsAvocado]

RUTA, JesseM and DrC,

I see that Mr. BS is back on track with the "Bell's Inequalities Triples Scam - BITS". Can you please verify if I’m a moron and Alain Aspect is a liar – or if it’s billschnieder who possesses both these noble attributes.

This is a slide from Alain Aspect himself, showing the measurements of the first famous EPR-Bell experiment which violated Bell's Inequality in 1982:

I see "Measured value" and the violation of "Bell's limits", but I don’t see Alain Aspect measuring "entangled triples"...??

So, what do you think...??

 

[Gordon Watson]

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

Dear Deepak,

Answering your OP in my terms:

Is action at a distance possible?

No; no way!

PS: Though it is immaterial to my general response above, I'd be happy to learn what this phrase might mean: ... as envisaged by the EPR Paradox?

With best regards,

JenniT

 

[billschnieder]

3) is ambiguous. It's true a dataset of pairs can be made to violate inequalities from a set of triples under certain sampling conditions, but not under the conditions assumed by Bell, where the choice of which two values to measure is random on each trial, and there is no correlation between the probability of a given triple and the choice of which pair to measure on a given trial.

I will let you respond to this one by yourself:

Bell's original proof did not concern any experiment, it was about comparing the theoretical predictions of local realism to the theoretical predictions of QM

An inequality such as X <= Y, means that "X" MUST always be less than or equal to "Y". If it is shown that in some cases X is greater than Y, the inequality is violated. It is the same as saying X can be greater than Y. There is nothing ambiguous there. It just means X is not necessarily less than Y as the inequality states.

I also notice that you actually agree with my point (3), except you claim that there are certain sampling assumptions in Bell's work which I have not taken into account. As you admitted in your later statement, Bell was never concerned about any actual experimental measurements or trials, so your earlier statement suggesting that Bell assumed data to be sampled in pairs and measured randomly on each trial is flatly wrong. There are no such claimed sampling assumptions in Bell's work which my point(3) supposedly violates. If you disagree point it out with a quote from Bell's work. Even if there was such an assumption, my point (3) still does not violate such a requirement.

I had hoped you would have a more substantive critique of those points.