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

[ThomasT]

1) You say: "Your argument here does not follow regarding vectors. So what if it is or is not true?", but the claim about this aspect of vectors is factually true. Read this carefully:
http://www.vias.org/physics/bk1_09_05.html
Note: Multiplying vectors from a pool ball collision under 2 different coordinate systems don't just lead to the same answer expressed in a different coordinate system, but an entirely different answer altogether. For this reason such vector operations are generally avoided, using scalar multiplication instead. Yet the Born rule and cos^2(theta) do just that.
2) You say: "I think you are trying to say that if vectors don't commute, then by definition local realism is ruled out.", but they don't commute for pool balls either, when used this way. That doesn't make pool balls not real. Thus the formalism has issues in this respect, not the reality of the pool balls. I even explained why: because given only the product of a vector, there exist no way of -uniquely- defining the particular vectors that went into defining it.

Again, I am missing your point. So what? How does this relate to Bell's Theorem or local realism?

I think that my-wan's point might be related to Christian's formulation of his (Christian's) LR model. Christian's point being that you need an algebra that can suitably represent the rotational invariance of the local beables -- which, in his estimation, Bell didn't represent adequately. According to Christian, Bell's ansatz misrepresents the topology of the experimental situation. Christian has produced 5, or so, papers (for anyone interested, go to arxiv.org and search on Joy Christian) that I know of trying to explain his idea(s). I don't fully understand what he's saying. That is, presently, I'm having difficulty incorporating what Christian is saying into my own 'intuitive' understanding of what I currently regard as the lack of depth in Bell's 'logical' analysis. Although, intuitively, I see a connection. I've read his papers and the discussions on sci.physics.research that Christian participated in a couple of years ago, and the impression I got was that he became frustrated with the lack of knowledge and preparation of those involved. Since then, I've seen nothing about his stuff and don't know if it's still under consideration for publication or not. Maybe he just abandoned it. Maybe someone should send him an email or something to find out what's what. (No, not me!) After all, the guy is a bona fide mathematical physicist who got his PhD under Shimony -- and he has published some respected peer reviewed stuff. It's very curious to me.) If he came to the conclusion that he was wrong, then wouldn't he be obligated, as a scientist, to say so? I assume that there are physicists and mathematicians here at PF qualified to critique his stuff. So, maybe they will contribute their synopses and critiques.

Anyway, I think my_wan's considerations about vectors are related to this. If I'm wrong, then please let me know why.

 

[ThomasT]

If this is a local theory in which any correlations between the two disturbances are explained by properties given to them by the common source, with the disturbances just carrying the same properties along with them as they travel, then this is exactly the sort of theory that Bell examined, and showed that such theories imply certain conclusions about the statistics we find when we measure the "disturbances", the Bell inequalities. Since these inequalities are violated experimentally, this is taken as a falsification of any such local theory which explains correlations in terms of common properties given to the particles by the source.

Bell's ansatz depicts the data sets A and B as being statistically independent. And yet we know that separately accumulated data sets produced by a common cause can be statistically dependent -- even when there is no causal dependence between the spacelike separated events that comprise the separate data sets -- precisely because the spacelike separated events have a common cause.

Bell has assumed that statistical dependence implies causal dependence. But we know that it doesn't. So, I ask you, is Bell's purported locality condition, in fact, a locality condition?

Virtually all physicists would agree that the violation of Bell inequalities constitutes a falsification of the kind of theory you describe, assuming you're talking about a purely local theory.

But that isn't what I asked.

What I asked was:

... given a situation in which two disturbances are emitted via a common source and subsequently measured, or a situation in which two disturbances interact and are subsequently measured, then the subsequent measurement of one will allow deductions regarding certain motional properties of the other.

Assuming the conservation laws are correct, then are these sorts of deductions allowable?

 

[ThomasT]

The EPR conclusion is most certainly not the view which is currently accepted.

The EPR conclusion was that qm is not a complete description of the physical reality underlying instrumental phenomena. Are you telling me that this isn't the view of a majority of physicists? If so, how do you know that? Every single physicist that I've talked to personally about this, whether they're familiar with EPR and Bell etc. or not, has said to me that they regard qm, in the sense of a description of the physical reality underlying instrumental phenomena, to be incomplete. This doesn't speak to why it's incomplete, or whether it must be incomplete, but just that it is incomplete. I conjecture that this is the view of a majority of working physicists. Now you can do a representative survey to prove that that conjecture is incorrect. But in the absence of such a survey, then a conjecture to the contrary is also just a conjecture.

That is because the EPR view has been theoretically (Bell) and experimentally (Aspect) rejected. But that was not the case in 1935. At that time, the jury was still out.

The EPR view stands as well today as it did in 1935. Either a real physical disturbance with real physical attributes is being emitted by the emitter or it isn't. If it isn't, then, according to a strict, realistic interpretation of the qm formalism, then the reality of B depends on a detection at A, and vice versa. Pretty silly, eh?

What is wrong with this view is that it violates the Heisenberg Uncertainty Principle. Nature does not allow that.

There's nothing in the EPR view that violates the uncertainty relations.

EPR says that two particles emitted from a common source are related wrt an applicable conservation law. So that, if the position of particle A is measured, then the position of particle B can be deduced, and if the momentum of particle A is measured, then the momentum of particle B can be deduced.

The uncertainty relations say that for a large number of similar preparations, the deviation from the statistical mean value of the position measurements will be related to the deviation from the statistical mean value of the momentum measurements by the following inequality: (delta q) . (delta p) >= h (where h is Planck's constant, the quantum of action).

As Bohr so eloquently, and yet so, er, cryptically, expressed, the uncertainty relations have no bearing on the relationship between a measurement that WAS made at A and a measurement that WAS NOT made at B.

Bottom line, the EPR argument has nothing to do with the uncertainty relations.

But it has everything to do with the, I conjecture, virtually universal acceptance that qm is an incomplete description of the physical reality underlying instrumental phenomena.

However, just so you don't take what I'm saying the wrong way. I don't see that an unassailably more complete description is possible. Even though there are LR models of entanglement that reproduce the qm predictions, there's absolutely no way to ascertain whether or not they're accurate depictions of an underlying reality. This was Bohr and Heisenberg's, et al., meeting of the minds, so to speak. Qm is, as a probability calculus of instrumental phenomena, as complete as it needs to be, and as complete as it can be without unnecessary and ultimately frustrating speculation regarding what does or doesn't exist or what is or isn't happening in the deep reality underlying instrumental phenomena. The point is that qm, as a mathematical probability calculus, can continue to be progressively developed, and technologically applicable, without any consensus regarding the constituents or behavior of proposed underlying 'elements of reality'.

 

[my_wan]

Do you just mean that local properties of the particle are affected by local properties of the detector it comes into contact with? If so, no, this cannot lead to any violations of the Bell inequalities.

I'll go through the computer model (virtual detectors) I used in your question below. I'll also explain the empirical based assumptions used.

Suppose the experimenters each have a choice of three detector settings, and they find that on any trial where they both chose the same detector setting they always got the same measurement outcome.

Naturally you get consistency between experiments, at least statistically. It really would be weird otherwise. But real experiments are limited to 2 setting choices at a time. The 3rd setting is a counterfactual from previous experiments. I doubt you've read the unfair coin example, an unfair coin with a tiny adjuster to set so it match a second 85% of the time, but by defining a 3rd simultaneous setting you are putting very severe non-random constraints on how it relates to 2 other settings. Both completely correlated with 1 and totally uncorrelated with the other, yet expecting this nonrandom choice to match stochastically with both based on statistical profiles pulled from previous experiments without such constraints. Neither classical nor QM mechanism allows this. Only QM is not explicitly time dependent so it's much harder to see the mechanism counterfactually in QM.

Then in a local hidden variables model where you have some variables associated with the particle and some with the detector, the only way to explain this is to suppose the variables associated with the two particles predetermined the result they would give for each of the three detector settings; if there was any probabilistic element to how the variables of the particles interacted with the state of the detector to produce a measurement outcome, then there would be a finite probability that the two experimenters could both choose the same detector setting and get different outcomes. Do you disagree?

Finite, maybe. Though there's at least some reason to believe nature is not finite. But assuming finite, I can also calculate the odds that all the air in the half of the room you are in spontaneously ends up in the other half of the room. The odds of it happening are indeed finite, but I'm not holding my breath just in case.

What do you mean by "assigning" coordinate systems? Coordinate systems are not associated with physical objects, they are just aspects of how we analyze a physical situation by assigning space and time coordinates to different events. Any physical situation can be analyzed using any coordinate system you like, the choice of coordinate system cannot affect your predictions about coordinate-invariant physical facts.

Quiet simple cases exist were quantities are not coordinate-invariant, and a very important one involves basic vector products. Consider:
http://www.vias.org/physics/bk1_09_05.html

The[/PLAIN] operation's result depends on what coordinate system we use, and since the two versions of R have different lengths (one being zero and the other nonzero), they don't just represent the same answer expressed in two different coordinate systems. Such an operation will never be useful in physics, because experiments show physics works the same regardless of which way we orient the laboratory building! The useful vector operations, such as addition and scalar multiplication, are rotationally invariant, i.e., come out the same regardless of the orientation of the coordinate system.

It states it "will never be useful in physics", yet both the Born rule and Malus Law involve just such a vector product if you presume there is some underlying mechanism. Given just a single vector magnitude it's not even possible to uniquely identify the vectors that it was derived from.

Anyway, your description isn't at all clear, could you come up with a mathematical description of the type of "hv model" you're imagining, rather than a verbal one?

My model is based on a computer model, virtual emitters and detectors.

Assumptions (I'll use photons and polarizations for simplicity):
1) A photon has a single unique default polarization, which is only unique in that upon meeting a polarizer at the same polarization it effectively has a 100% chance of passing that polarizer.
2) The odds that a photon will pass through a polarizer that is offset from that photon default polarization is defined by cos^2(theta), Malus Law.
3) A bit field is set to predefine passage through a polarizer it meats at various settings, with the odds of a bit being predefined as 1 (for passage) determined by a random number generator with a min/max of 0/1 that rolls less than cos^2(theta) when created at the emitter.
4) A random number with a min/max of 0/359.5, rounded to half degree increments, predefines the default polarization at the emitter. These can be rotated with impunity.

For computer modeling a default polarization and a bit field is set. I used 180 bit field, which predefines passage or not for each 1/2 degree over 90 degrees, reversed for every other 90 degrees. The odds that a 10 degree bit, for instance, will be predefined 1 is cos^2(10). Anticorrelated photons are simply flipped 180 degrees, with the same bit field. The photons can be randomly generated and written to a text file. I have lots of improvements to try, but haven't got to it yet.

The formula, when a photon meets a detector is simply (polarizer1 - photon1) and (polarizer2 - photon2) at the other end. Then simply count that many bits into the bit field to see if a detection occurs. No Malus Law used here because it's built into the statistics of the bit field. Detections are returned before comparisons are made between polarizer1 and polarizer2.

This only works to match QM predictions if 1 of the polarizer settings is defined to be 0. Yet you can rotate the photons coming from the emitter with impunity, without effecting the coincidence statistics. So there exist no unique physical state at certain rotations. Neither polarizer directly references the setting of the other polarizer. Only the difference between the photons default polarization and the polarizer setting it actually comes in contact with is used to define detections.

The 0 angle is the biggest issue. You could also add another 719 180 bit fields, for 1/2 degree increments, to undo the 0 degree requirement on one of the detector. This would blow up into a huge, possibly infinite, number of variables in real world conditions, but if quantum computers work as well as expected this shouldn't be an issue.

I'm not happy with this, and have a lot of improvements to try, when I get to it. Including using predefined ranges instead of bit fields, and non-commutative vector rotations in an attempt to remove the coordinate rotations as I change a certain detector setting. I have my doubts about these.

 

[my_wan]

Please tell me what theta represents physically.

As I asked already:
How you define theta? Is it angle between polarization axis of polarizer (PBS) and photon so that we have theta1 for H and theta2 for V with condition that theta1=theta2-90?
Or it's something else?

Theta is simply a polarizer setting relative to any arbitrary coordinate system. However, it only leads to valid counterfactual (after the fact) comparisons to route statistics at a 0 setting, but it makes no difference which coordinate choice you use, so long as the photon polarizations are uniformly distributed across the coordinate system.

 

[JesseM]

Bell's ansatz depicts the data sets A and B as being statistically independent.

Only when conditioned on the appropriate hidden variables represented by the value of λ. When not conditioned on λ, Bell's argument says there can certainly be a statistical dependence between A and B, i.e. P(A|B) may be different than P(A). Do you disagree?

And yet we know that separately accumulated data sets produced by a common cause can be statistically dependent -- even when there is no causal dependence between the spacelike separated events that comprise the separate data sets -- precisely because the spacelike separated events have a common cause.

Yes, and this was exactly the possibility that Bell was considering! If you don't see this, then you are misunderstanding something very basic about Bell's reasoning. If A and B have a statistical dependence, so P(A|B) is different than P(A), but this dependence is fully explained by a common cause λ, then that implies that P(A|λ) = P(A|λ,B), i.e. there is no statistical dependence when conditioned on λ. That's the very meaning of equation (2) in Bell's original paper, that the statistical dependence which does exist between A and B is completely determined by the state of the hidden variables λ, and so the statistical dependence disappears when conditioned on λ. Again, please tell me if you disagree with this.

Bell has assumed that statistical dependence implies causal dependence.

No, he didn't. He was explicitly considering a case where there is a statistical dependence between A and B but not a causal dependence because the dependence is fully explained by λ. In the simplest type of hidden-variables theory, λ would just represent some set of hidden variables assigned to each particle by the source when the two particles were created, which remained unchanged as they traveled to the detector and which determined their responses to various detector settings.

It would really help if you looked over my lotto card analogy in post #2 here! Your comments suggest you may be confused about the most basic aspects of Bell's proof, so instead of trying to understand the abstract equations in his original paper, I think it would definitely help to look over a concrete model of a situation where we propose a simple hidden-variables theory (involving a common cause, namely the cards being assigned identical 'hidden fruits' by the source) to explain a statistical dependence in observed measurements (the fact that whenever Alice and Bob choose the same box on their respective cards to scratch, they always find the same fruit behind it).

So, I ask you, is Bell's purported locality condition, in fact, a locality condition?

Properly understood, yes it most certainly is.

Virtually all physicists would agree that the violation of Bell inequalities constitutes a falsification of the kind of theory you describe, assuming you're talking about a purely local theory.

But that isn't what I asked.

What I asked was:

given a situation in which two disturbances are emitted via a common source and subsequently measured, or a situation in which two disturbances interact and are subsequently measured, then the subsequent measurement of one will allow deductions regarding certain motional properties of the other.

That paragraph is not even a question, so I would say that's not what you asked. My comment above was in response to your question (which I quoted in my post), "Do you doubt that this is the view of virtually all physicists?" And I understood "this is the view" to refer to your earlier comment "The EPR view was that the element of reality at B determined by a measurement at A wasn't reasonably explained by spooky action at a distance", i.e. specifically the view that correlations in quantum physics could be explained by this sort of common cause, in which case this is not the view of virtually all physicists. On the other hand, if you were just asking whether all physicists would agree there are some situations (outside of QM) where correlations between separated measurements can be explained in terms of common causes, then of course the answer is yes.

Assuming the conservation laws are correct, then are these sorts of deductions allowable?

Here you seem to be asking a new question, and my answer is "yes, in cases where two disturbances are emitted by a common source, observations of one may allow for deductions about the other". And of course, the whole point of Bell's argument was to consider whether or not the observed correlations between measurements on entangled particles could be explained in terms of this sort of "common cause" explanation in a local realist theory. The conclusion he reached was that any such explanation would imply certain Bell inequalities, which are experimentally observed to be violated in quantum experiments.

 

[ThomasT]

Only when conditioned on the appropriate hidden variables represented by the value of ?. When not conditioned on λ, Bell's argument says there can certainly be a statistical dependence between A and B, i.e. P(A|B) may be different than P(A). Do you disagree?

Does the form, Bell's (2), denote statistical indepencence or doesn't it?

Yes, and this was exactly the possibility that Bell was considering! If you don't see this, then you are misunderstanding something very basic about Bell's reasoning. If A and B have a statistical dependence, so P(A|B) is different than P(A), but this dependence is fully explained by a common cause λ, then that implies that P(A|λ) = P(A|λ,B), i.e. there is no statistical dependence when conditioned on λ. That's the very meaning of equation (2) in Bell's original paper, that the statistical dependence which does exist between A and B is completely determined by the state of the hidden variables λ, and so the statistical dependence disappears when conditioned on λ. Again, please tell me if you disagree with this.

It seems that you're saying that if the disturbances incident on a and b have a common cause, then the results, A and B, can't be statistically dependent. Is that what you're saying?

... the whole point of Bell's argument was to consider whether or not the observed correlations between measurements on entangled particles could be explained in terms of this sort of "common cause" explanation in a local realist theory. The conclusion he reached was that any such explanation would imply certain Bell inequalities, which are experimentally observed to be violated in quantum experiments.

Yes, well, we disagree then on the depth of Bell's analysis, or simply on the way his analysis and result is communicated. The problem is that viable LR models of entanglement exist. Would you care to look at one and refute it -- either wrt to its purported locality or reality or agreement with qm predictions?

 

[DrChinese]

Quiet simple cases exist were quantities are not coordinate-invariant, and a very important one involves basic vector products. Consider:
http://www.vias.org/physics/bk1_09_05.html

We are not discussing whether 2 measurements commute or not. Or two vector operations. We are discussing whether 2 measurements on separated particles have various attributes. So this statement and the related example are completely meaningless in the context of this discussion. I really wish you would stop mentioning it as it leads us nowhere useful.

We understand that your model lacks rotational invariance in that it works with a reference angle of 0 and not at others. And no, it is not OK that you can define any angle as 0 to make it appear to work. Your "trick" works because you are effectively communicating Alice's setting to Bob or vice versa. Whether or not vectors add in all coordinate systems does not change this point in any way.

 

[ThomasT]

JesseM, do you think that most physicists equate EPR's spooky action at a distance with quantum correlations?

 

[JesseM]

Does the form, Bell's (2), denote statistical indepencence or doesn't it?

You haven't defined what you mean by "statistical independence". I think I made clear already that two variables can be statistically dependent in their marginal probabilities but statistically independent when conditioned on other variables.

Could you please answer the questions I ask you in my posts, like this one?

When not conditioned on λ, Bell's argument says there can certainly be a statistical dependence between A and B, i.e. P(A|B) may be different than P(A). Do you disagree?

It seems that you're saying that if the disturbances incident on a and b have a common cause, then the results, A and B, can't be statistically dependent. Is that what you're saying?

If the common cause is the complete explanation for the statistical dependence in the marginal probabilities, then when conditioned on the common cause they wouldn't be statistically dependent (i.e. if you already know precisely what properties were given to system A by the common cause which also gave some related properties to system B, then learning about a later measurement on system B will tell you nothing new about what you are likely to see when you measure system A). Do you disagree with that? If you do disagree, can you think of any classical examples where we have correlations that are completely explained by a common cause, yet where the above would not be true?

Of course you could have a more complicated situation where there were multiple common causes, and perhaps also some direct causal influences between A and B. But then the given common cause wouldn't be the complete explanation for the correlation observed between measurements on A and B.

Yes, well, we disagree then on the depth of Bell's analysis.

OK, but do you want to engage in an actual substantive discussion about the details of his analysis and whether his assumptions are justified? If so then I would ask that you please answer my direct questions to you, and also address the examples and arguments I present like the lotto card analogy in post #2 here or the argument I made about conditioning on complete past light cones, and what this would imply in both deterministic and probabilistic theories, in this post. Of course there's no need to respond to all of this immediately, but if you are intellectually serious about exploring the truth and not just trying to engage in rhetorical denunciations, then I'd like some assurances that you do plan to address my questions and arguments seriously if we're going to keep discussing this stuff.

 

[DrChinese]

Does the form, Bell's (2), denote statistical indepencence or doesn't it?

It seems that you're saying that if the disturbances incident on a and b have a common cause, then the results, A and B, can't be statistically dependent. Is that what you're saying?

A common cause is assumed. Statistical correlation of A and B is assumed as well. Even perfect correlations can be explained, all within Bell (2). There is no problem with any of this. This is simply a restatement of what EPR was trying to say.

The problem is getting this to agree to the QM expectation values. There are a variety of constraints in this as my_wan has discovered. Under scenario a), the Malus relationship does not hold except at privileged angle settings. Under scenario b), an infinite or at least very large amount of data must be encoded. And both of these scenarios are BEFORE we come to terms with a Bell Inequality.

So my point is that for everyone attacking Bell (2), you are coming at it backwards. It is a generic statement, and does not provide any particular insight into the EPR issue at all. Any way you want to express the statement "The result A does not depend on setting b, and vice versa" would work here. Bell calls this requirement essential because it is his version of locality. (Or call it "local causality" if that is a preferable label.) Bell assumed his version would not cause anybody to have a cow, that it would be accepted as a mathematical version of the "...A not dependent on b..." statement. So whether or not there is a statistical connection, that really makes no difference. Since this is assumed by everyone. So Bell (2) is not an expression of the independence of statistical correlations A and B. It has to do with the independence of A and b, and B and a. If your model has A dependent on b, then it fails test #1. Because it is not local.

 

[ThomasT]

You haven't defined what you mean by "statistical independence".

Factorability of the joint probability. The product of the probabilities of A and B. Isn't that the definition of statistical independence?

 

[DrChinese]

Factorability of the joint probability. The product of the probabilities of A and B. Isn't that the definition of statistical independence?

a and b are different than A and B. A and B do not need to be independent.

 

[ThomasT]

a and b are different than A and B. A and B do not need to be independent.

Exactly. But that's how Bell's model denotes them. In Bell's model, the data sets A and B are independent.

 

[ThomasT]

So Bell (2) is not an expression of the independence of statistical correlations A and B.

Are you sure about that? I think it's been demonstrated that Bell's ansatz reduces to the probability definition of statistical independence. If you think otherwise then maybe you should revisit the posts in this and other threads dealing with that.

 

[ThomasT]

DrC, the view of many physicists, including past discussions I've had here at PF, indicate that Bell's idea was that if the data sets A and B were statistically dependent, then they must be causally dependent. Of course, we know this is wrong.

 

[DrChinese]

Are you sure about that? I think it's been demonstrated that Bell's ansatz reduces to the probability definition of statistical independence. If you think otherwise then maybe you should revisit the posts in this and other threads dealing with that.

I have stated many times: A and b, not A and B. The result A is definitely correlates with B. The question is: does A change with b? It shouldn't in a local world. In other words: if Alice's result changes when spacelike separated Bob moves his measurement dial, then there is spooky action at a distance. I know you will agree with that statement.

From the EPR conclusion: "This makes the reality of P and Q depend upon the process of measurement carried out on the first system in any way. No reasonable definition of reality could be expected to permit this." They are saying the same thing as Bell (2).

And in Bell's words: "The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b." Which he then presents in his form (2). There is no restriction on the correlation of A and B in this.

So the data points for A with setting a come out the same regardless of the value of b. Of course the correlation of A and B may change with a change in a or b. Bell (2) is not saying anything about that. If you doubt this, just re-read what Bell said above. Or what EPR said.

 

[DrChinese]

DrC, the view of many physicists, including past discussions I've had here at PF, indicate that Bell's idea was that if the data sets A and B were statistically dependent, then they must be causally dependent. Of course, we know this is wrong.

There is nothing wrong with causality in this situation. I mean, the entire point is that the pairs are clones (or anti-clones) of each other because they were created at the same time. The question is whether there is observer independence in the outcomes. Whether the reality of P and Q are independent of what goes on elsewhere. Whether the result A is dependent on setting b.

And as far as anyone knows, this is "possible" within constraints when you consider Bell (2) by itself. This has been demonstrated by who knows how many local realistic papers. But of course all this falls apart when you add the realism requirement. EPR said that it was possible to constrain reality to just the number of observables that could be predicted simultaneously (1), but that was too restrictive (in their opinion). So by then applying the less restrictive definition of reality which they claim as reasonable (2 or more), Bell obtains his famous result.

 

[DrChinese]

Exactly. But that's how Bell's model denotes them. In Bell's model, the data sets A and B are independent.

No, that is my point. You have misinterpreted Bell (2). How many times must I repeat Bell:

"The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b."

"The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b."

"The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b."

Yes, I am pretty good with ^V. And there can be a connection between A and B. In fact, there has to be to have an element of reality according to EPR. It was assumed that A and B would be perfectly correlated when a=b. That is how you predict the outcome of one without first disturbing it.

 

[ThomasT]

I have stated many times: A and b, not A and B. The result A is definitely correlates with B. The question is: does A change with b? It shouldn't in a local world. In other words: if Alice's result changes when spacelike separated Bob moves his measurement dial, then there is spooky action at a distance. I know you will agree with that statement.

From the EPR conclusion: "This makes the reality of P and Q depend upon the process of measurement carried out on the first system in any way. No reasonable definition of reality could be expected to permit this." They are saying the same thing as Bell (2).

And in Bell's words: "The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b." Which he then presents in his form (2). There is no restriction on the correlation of A and B in this.

So the data points for A with setting a come out the same regardless of the value of b. Of course the correlation of A and B may change with a change in a or b. Bell (2) is not saying anything about that. If you doubt this, just re-read what Bell said above. Or what EPR said.

You miss the point. Bell's ansatz denotes that the data sets A and B are statistically independent.

 

[DrChinese]

You miss the point. Bell's ansatz denotes that the data sets A and B are statistically independent.

No. They aren't independent. Bell never mentions that point.

 

[ThomasT]

No, that is my point. You have misinterpreted Bell (2). How many times must I repeat Bell:

"The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b."

"The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b."

"The vital assumption is that the result B for particle 2 does not depend on the setting a, of the magnet for particle 1, nor A on b."

Yes, I am pretty good with ^V. And there can be a connection between A and B. In fact, there has to be to have an element of reality according to EPR. It was assumed that A and B would be perfectly correlated when a=b. That is how you predict the outcome of one without first disturbing it.

You can repeat anything you want as much as you want. The fact is that Bell's model says that the data sets A and B are independent.

This point is important, so if you dispute it, then you'll have to demonstrate why.

And yet we know from the experimental designs that the data sets, A and B, aren't independent. And we also know that this statistical dependence doesn't have to have anything to do with a causal connection between A and B or A and b or B and a or B and A. A local common cause is sufficient to explain the statistical dependencies that are observed. Period. If you think that Bell's theorem proves that there is no local common cause to the correlations, then you're just not thinking about this like a physicist. In fact, I'll submit this: many physicists, maybe even most, having neither the time nor the inclination to delve very deeply into Bell's theorem, have accepted the common view that all local realistic theories of entanglement are impossible. What do they care. It has nothing to do with their research or their experiments or their grants. Period.

Of course, imo, they're wrong. But so what? It doesn't affect their programs one bit. So I reject your appeals to 'a majority of physicists' think this or that. I've issued you a challenge and asked you to clarify what you mean by your 'requirement'. Please address that issue. It's most difficult to learn anything from obfuscations.

 

[ThomasT]

No. They aren't independent. Bell never mentions that point.

It doesn't matter if he 'mentions' it. It's there, in the model.

On the one hand, in some posts, you say that it doesn't matter if Bell says this or that. And on the other hand, when it suits your purpose, you appeal to what Bell did or didn't say.

Well, I'm telling you now, the arguments that have been presented have nothing to do with what Bell did or didn't say about any of his formal presentations. All we're concerned with are the formalisms. Period.

So, you'd better forget about what 'most' physicists say or believe, and what Bell said or believed, and just look at what he presented as a model of a certain experimental situation. It happens to be wrong. And we're trying to determine exactly what's wrong with it.

 

[DrChinese]

It doesn't matter if he 'mentions' it. It's there, in the model.

On the one hand, in some posts, you say that it doesn't matter if Bell says this or that. And on the other hand, when it suits your purpose, you appeal to what Bell did or didn't say.

Well, I'm telling you now, the arguments that have been presented have nothing to do with what Bell did or didn't say about any of his formal presentations. All we're concerned with are the formalisms. Period.

So, you'd better forget about what 'most' physicists say or believe, and what Bell said or believed, and just look at what he presented as a model of a certain experimental situation. It happens to be wrong. And we're trying to determine exactly what's wrong with it.

It would be nice if you would mention that it is the 1965 paper which I quote, not his later writings. And it is that same paper which is usually referenced by authors, not his later writings. There has never been much question about the respect I give that paper.

Now, after saying the words, Bell presents the mathematical form which is the SAME as the words. There is no question about this to most anyone. But I see that for many, this can be a bit confusing. So I will point out EXACTLY what his (2) says:

There is a result function for Alice, A(a, lambda), which has no dependence on b. There is a result function for Bob, B(b, lambda), which has no dependence on a. These share a common dependence on a set of hidden variables or hidden functions. I believe you can see this point for yourself. And there is the correlation function, P(a, b) which we would expect to match the quantum expectation value, which is Bell's (3). For a=b, the result is -1 for the singlet state. I believe you can plainly see this point.

Now, where is the above any different than what I have told you: Bob's result B is independent of Alice's setting a. But there is definitely a correlation between A and B, which is in fact -1 when a=b.

I really don't know how to make it much clearer. Show me any respected author who says that Bell (2) is a requirement that outcomes A and B are statistically unrelated. Or if the author is not respected, at least give me a funny quote.

 

[DrChinese]

And yet we know from the experimental designs that the data sets, A and B, aren't independent. And we also know that this statistical dependence doesn't have to have anything to do with a causal connection between A and B or A and b or B and a or B and A. A local common cause is sufficient to explain the statistical dependencies that are observed. Period. If you think that Bell's theorem proves that there is no local common cause to the correlations, then you're just not thinking about this like a physicist. In fact, I'll submit this: many physicists, maybe even most, having neither the time nor the inclination to delve very deeply into Bell's theorem, have accepted the common view that all local realistic theories of entanglement are impossible. What do they care. It has nothing to do with their research or their experiments or their grants. Period.

Of course, imo, they're wrong. But so what? It doesn't affect their programs one bit. So I reject your appeals to 'a majority of physicists' think this or that. I've issued you a challenge and asked you to clarify what you mean by your 'requirement'. Please address that issue. It's most difficult to learn anything from obfuscations.

OK, you are going off the deep end again. There are a lot of physicists out there who DO follow Bell tests very closely, and it is these that I generally quote. Zeilinger and Aspect being just 2, but there are a lot of very well respected scientists out there - Gisin, Weihs, Mermin, Greenberger, many many more. I am not invoking the authority of those who don't know the field. So I would recommend you cease your diatribe, it really reflects poorly. These guys know their stuff, theory and history. And every day they are dreaming up and running experiments that would be impossible in a local realistic world. So please, don't speak like a fool.

Second, as I have repeatedly told you, there IS a statistical relationship between the results of Alice and Bob. And that IS effectively due to a common cause or whatever you want to call it. I call it a conservation law. Also, a local connection MIGHT be able to follow the requirements of Bell (2) and Bell (3) but cannot survive the Bell final result (which rules out all local realistic theories).

And third, it is not my requirements which are in question here. It is the requirement of EPR, as I quoted you earlier, that there be 2 or more simultaneous elements of reality. In Bell's case, there are 3: a, b and c.

 

[ThomasT]

It would be nice if you would mention that it is the 1965 paper which I quote, not his later writings. And it is that same paper which is usually referenced by authors, not his later writings. There has never been much question about the respect I give that paper.

Now, after saying the words, Bell presents the mathematical form which is the SAME as the words. There is no question about this to most anyone. But I see that for many, this can be a bit confusing. So I will point out EXACTLY what his (2) says:

There is a result function for Alice, A(a, lambda), which has no dependence on b. There is a result function for Bob, B(b, lambda), which has no dependence on a. These share a common dependence on a set of hidden variables or hidden functions. I believe you can see this point for yourself. And there is the correlation function, P(a, b) which we would expect to match the quantum expectation value, which is Bell's (3). For a=b, the result is -1 for the singlet state. I believe you can plainly see this point.

Now, where is the above any different than what I have told you: Bob's result B is independent of Alice's setting a. But there is definitely a correlation between A and B, which is in fact -1 when a=b.

I really don't know how to make it much clearer. Show me any respected author who says that Bell (2) is a requirement that outcomes A and B are statistically unrelated. Or if the author is not respected, at least give me a funny quote.

The 'form' of Bell's (2) says, explicitly, that the data sets A and B are independent.

Look, I don't care about this right now. I already understand it. I want you to tell me what your LR 'requirement" means. Please do that. Thank you.

 

[ThomasT]

I'm waiting ...

 

[ThomasT]

Look, I have some other stuff to do soon. I want the 'casual reader' to understand that you're unable to refute a simple LR model of entanglement.

There's no need to be alarmed. It will only hurt for a second or two.

 

[DrChinese]

I want the 'casual reader' to understand that you're unable to refute a simple LR model of entanglement.

You are proof of the existence of many worlds.

ThomasT, you are really messing yourself up with this one. I appreciate that you have convinced yourself that you have brilliantly deduced the "flaws" in Bell that no one else has had the keen insight to spot. But I don't need to prove Bell, that has already been done X times over. And you have not put forth ANYTHING, much less a candidate to refute.

Any casual reader who mistakenly takes you as an authority on this subject will end up disappointed in the end. But please, continue your idle boasting if it makes you feel better.

 

[DrChinese]

I'm waiting ...

And if you are holding your breath, you will eventually turn blue. I am pretty certain of that.