Bell's Theorem and Nonlocality

I have given a sufficient demonstration to prove that entanglement is a fact, not just a theory, in the same way that gravity is a fact and not just a theory. Any claims of local determinism invariably lead to a prediction which decisively disagrees with experimental fact. If you want to say that the Bell test experiments don't constitute a demonstration of fact, then you may as well say that space, time, mass, particles and electric charge aren't proven facts either.

 

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So you don't want to let me present my case?

That is a new and different position from your claims in the presentation up to now. Is it possible you can't show one link that supports your claim that entanglement is fact?

It is obvious that your "pretend falsification of the position you claim is mine", but which in fact is your own straw man, is coming apart at the seams. Are you now finding yourself in corner, and are resting to threats again? Is the "real" CptBork now in the room?

 

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That is not responsive to my post #55. Your response is just false, you have not demonstrated that entanglement is fact. It is not a fact. Is that the means you plan to use to avoid an admission that is clearly required. You admit that entanglement is not a fact, or you show where the theory was elevated to a fact.

 

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I declare the following: The math proof I just completed demonstrates that entanglement is a fact, because any attempt to account for nature without it is guaranteed to make predictions in significant disagreement with existing experiments. Tell me how my math proof fails to demonstrate this.

 

Does the math proof include the application of the theory of entanglement? If so, the proof is not that entanglement is fact, it is proof that the theory of entanglement is a theory used in the process of applying the postulates of QM to support the math.

You have not responded to this question either, and it goes back to the very beginning of the bad air between us. I told you back on Cav577's thread that only interpretations that could be verified or falsified using QM, as it stands, were tested. Do you deny I said that? That fact is important because the speculations that I have put forth, after stating that my position is that QM might not be complete, are hypotheses that cannot be tested, and cannot be proven or falsified by QM as it exists. Do you see the distinction?

 

The proof doesn't say anything about the theory of entanglement, and it doesn't depend on any details other than the knowledge that the theory being disproved relies on local hidden variables to explain nature.

I've said all along that you don't need to know or assume anything about QM to show that local hidden variable theories can't possibly match reality, and the proof makes no assumptions whatsoever about QM. Quantum mechanics only comes into play when you ask what kinds of existing theories do correctly predict the results of Bell tests.

 

so in summary you have managed to show that hypothetical local hidden variables are not applicable?
After all, is not the hypothesis of local hidden variables just another attempt to provide a theoretical contra to the notion of "actual" entanglement?

 

Correct, they can't possibly account for existing experimental results.

Also correct. If local hidden variables can't explain reality, then the only possible alternative is some form of non-local entanglement, by definition.

 

Do all those experiments involve photons?

What is the simplest of those experiments?

Do you think those experiments disprove aether?

 

QQ, you may remember this discussion we had starting in and around this post.

In that series of posts, we touched on the theory of entanglement. I mentioned, "I wonder if particles said to be entangled actually have their states superimposed, or if they each have their state established at the moment that they are produced, and we only are then able to determine which particle is in which state when we observe one of them?"

My question about entanglement and superposition conveys the view that entanglement and superposition may not be fact, and instead that they are theory; not fact or reality in the scientific sense.

You didn't reply to that specifically, and now I'm not sure of the meaning of your post last night. I am saying that entanglement and superposition are part of the Quantum Theory postulates that CptBork depends on in the experiments associated with his mathematical proof. He now says they are not. Before I respond to his recent posts, can you acknowledge this post and respond about your meaning in your post #67?

 

Yes they do, and the involve creating entangled photons with their states superimposed, as I understand the Aspect experiments.

The Aspect experiments are famous and are available to review. Simple may not be exactly the right word, but if you read them you can understand that entanglement is a part of the process.

Thank you for asking!

 

In principle you can do the same kind of experiment with electrons and other spin-1/2 fermions, replacing "polarized/not polarized" on a given axis with "spin up/spin down", where the net spins of the two particles add to zero whenever measured on the same axis. I'm not specifically aware what kind of work has been done in this area, but most experimental tests involving Bell's Theorem are done with photons and those are, according to Wikipedia, the only ones for which all possible loopholes in the argument have been thoroughly addressed.

As mentioned by quantum_wave, Alain Aspect's experiments were the first tests of Bell's Theorem and probably the simplest, but subsequent experiments with different configurations have since been conducted in order to close all the loopholes and workarounds in Aspect's result.

No, but I do think other unrelated experiments disprove it (if you're looking for an aether of the type hypothesized by 19th/early 20th century physicists such as Hendrik Lorentz).

 

Ok, I've watched several videos and read more than few articles about this theorem. As I understand so far it is defined according to predictions of QM, and as such it might not be applicable outside QM because those predictions might not actually be true, or they might be true but only in terms of QM itself.

I'd like to make sure now I understand not only what is going on in the experiment, but more importantly why is it set up the way it is.

There are three different polarization axis A, B, C which are selected before or after photons are emitted?
What is it we measure after the photons are polarized, some binary value like spin up and spin down?

When both photons are polarized along the same axis, say A, we always get deterministic result?
That is if we measure photon 1 has spin down, then photon 2 will always have spin up?

What is the purpose of having three different axis, does it have anything to do with uncertainty principle?

 

CptBork, I had expected that after you presented the math proof, you were going to connect it with experimental results testing Bell's Theorem and the proof. The proof and theorem alone prove nothing, without the experimental results. And the experimental design and results are where the question, may remain. Do the experiments prove or just support the theorem and math proof? How do you address any systematic or design issues that could influence the conclusions?

As I mentioned earlier I am skeptical about any FTL process. A hold over from my early background associated with relativity and dislike of QM. The later something I have been trying to overcome. So I was and am interested in the introduction of how and why the experimental tests support or prove, the theorem and math proof.

So far it seems to me you have presented a clear argument and basis for your position, but stopped short of connecting that with the experimental evidense and data.., the only part of the arguement that could be presented as proving the theorem.

Can you extend the discussion to the test and how and why they prove the theorem and why there exclude any other as yet understood explanation of the results?

I am interested in your thoughts on this.

 

It seems there's a lot of confusion here, and quantum_wave has expressed a similar misunderstanding. Bell's Theorem in its original form states that there's a certain testable prediction made by any local hidden variable theory which is different from the prediction made by quantum mechanics, and tests based on this theorem weren't technologically possible for another 15-20 years. Whether quantum mechanics is valid or not doesn't change the fact that any local hidden variable theory makes a testable prediction which differs substantially from experimental results, although quantum mechanics does indeed correctly predict these results.

The measurement axes for detecting polarization are decided after the photons are emitted, and close enough to the time of measurement so that no lightspeed signals can communicate this choice from one particle to the other before both are measured. The binary value you look for is whether the photon is polarized at that angle ("+") and passes through the associated filter, or not polarized at that angle and blocked by the filter.

I don't think the photons are set up with any spin along the axis of motion, I think they're linearly polarized, but I'm not going to pretend I'm an expert on the precise experimental setups. In any case, whenever the same axis of measurement is chosen at both ends of the lab, they always yield the same polarization values just as predicted by deterministic and quantum theories, it's only when the axes are different that you get interesting results.

I think if you restrict the argument to looking at only 2 axes, then quantum mechanics and local hidden variable theories predict the same result, or else the local hidden variable prediction is not automatically inconsistent with experiment (I could check it directly and perhaps get back to you on that if you're genuinely interested). What I've presented here is a very simple theorem, but I think there's a good reason it took almost 4 decades after the introduction of modern quantum theory before someone discovered it, there's a degree of ingenuity in the argument. Also note that the measurement axes don't necessarily have to be \(120^\circ\) apart, but then the quantum prediction changes from 25% to something else (as far as I'm aware, the experimental results still contradict local hidden variable theory predictions for any choice of angles, but again I'd have to play with the math and see).

 

Polarizing photons and then measuring some aspect of polarization is confusing. Experiment with spin up and spin down electrons makes it much more clear what is a part of the setup (input) and what is actually measured (output). Just saying.

So we have determinism. If we were testing any law of classical physics that would be sufficient, we would conclude the relation between photons is simply due to initial conditions when they were emitted.

Why is that not enough? How is that not conclusive? Why do we need three different polarization axis, randomness and statistics? It's because of Heisenberg's uncertainty principle. So I question whether is this principle indeed true and whether it really applies to anything else but Quantum Mechanics.

 

Firstly your question raises a massive issue confronting science in it's quest to move on from it's current paradigm. So the short answer is no, I can not give an explanation in a way that you will be satisfied.

Years ago Ernst Mach (1938-1916) alluded [documented indirect reference] to something that influenced Einstein significantly and it was directly associated with how inertia, universal constancy etc could be a form of continuous supposition on a a universal scale [ my interpretation ok?]
The discussions between the two scientists, Mach and Einstein, would have been extraordinary and rather outrageous given the times. [Mach being very much the senior [mature] mentor of the two. IMO]

Apparently according to wiki Einstein interpreted Mach as: "...inertia originates in a kind of interaction between bodies..."
Now keep in mind we are talking about discussions and insights prior to GR's development and that those discussions were involving the entire universal structure.

GR failed to satisfy Mach's hypothesis and no theory has yet been able to provide solutions for universal constancy of inertia/Gravitation being "EXACTLY" uniform across such a huge diversity and distance involved as is obvious when considering the universe holistically. Or to take it to it's 'inth' and absurd degree, Why the laws of physics would be or are universally constant and consistent.

I state the above because it leads to my thoughts about Quantum Supposition and how IMO the universe can be entirely superimposed in to one single zero point. [as I attempted to explore in the other thread about light cones, HSP's and delta t=0] http://www.sciforums.com/showthread.php?141347-Intriguing-question-about-Time-Physics-and-SRT-in-general

However for QM to state that all things are in a state of zero point supposition, thus generating that permanent inter-connectivity between all things would on the surface render "relative time" as being discounted as being a temporary side track from absolute time, thus seriously conflicting with SRT, and therefore GR. I do not believe that many scientists of worth are prepared to make a claim of such significance.

Therefore quantum entanglement remains in a realm of, real and observable scientific fact with pseudo-scientific explanations. [due to it's obvious potential to conflict GR and SRT. IMO]

My personal belief is that all particles are in a permanent state of Quantum Supposition and it is only when we deliberately attempt to determine this state that it is revealed. [and dramatically changed in the process in most cases]
This is because at delta t= 0 [ eg: at mark 10 am] all dimensions are zero. Thus all things are in a state of zero point supposition. [entanglement]

Suffice to say that IMO the sheer fact that all things share the "exact same gravitational constant" indicates beyond any reasonable doubt that all things are in a state of permanent supposition and logically no further examples are necessary to prove the point.

Just thoughts and I hope I haven't confused the issue even more than it is.

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I chose to discuss polarization because that's what's generally used in experimental tests, but I acknowledge it can seem confusing at first glance. When you shine a classical beam of light through a polarization filter, it comes out polarized along a specific axis perpendicular to its motion. If you then place a second polarization filter in such a way that the light coming through it is polarized at angle \(\theta\) relative to the first axis, then the amount of light making it through both filters is proportional to \(\cos^2\theta\), which falls to zero when the axes are perpendicular. In the case of photons travelling through the filters one by one, all photons making it through the first filter have polarization along the first axis, and then \(\cos^2\theta\) is the fraction of that total which will acquire polarization along the second axis and pass through the second filter when they encounter it.

That only applies in cases where the two measurement axes coincide, and I'm saying we need to look specifically at the data subset in which the two axes don't coincide to see that nature can't be both local and deterministic. Quantum physics says that a system in a given state retains that state until it's specifically disturbed, so if two photons started off in a superposition state where they're guaranteed to have the same polarization along any given axis, they'll retain identical polarization upon measurement on that axis just as they would in a deterministic theory. In cases of spin measurement, you usually start with a system in which the net spin is zero, so that the two spins have to be opposite when measured on the same axis.

You can use local hidden variables to explain the results when the axes of measurement coincide, that's pretty simple and straight forward. What local hidden variables can't explain is why the off-axis correlation rate is 25% for the setup I detailed, when any local hidden variable theory predicts that it should be at least 33% or higher.

Bell's Theorem doesn't prove the Heisenberg Uncertainty Principle, nor does it in any way depend on this result. All it conclusively proves is that local hidden variable theories cannot possibly match with known experiments, whereas the fact that the non-local quantum predictions match the experimental results only serves as a plausibility argument for the correctness of quantum mechanics.

 

Ay, caramba! Of course the measurements only coincide if they are kept in the same axis. If you swing them off their original axis into different angles you break their initial symmetry. The same would happen with two billiard balls if you gave them opposite spins and send them in opposite directions. If you then deflect them by the same amount in the opposite direction (mirrored angle) they will preserve their relative spin difference. Note that imparted change in spin due to deflection friction is relative to the deflection angle. So then if you deflect them by different amount you will break their initial symmetry and they will not be correlated any more. Has no one noticed this before?

Can I use unhidden and very obvious variables with the size of a billiard ball?

I didn't say it proves it nor that it depends on it. I don't know and it's not important. What is important is that Uncertainty Principle is the reason why the setup has three different axes of polarization. Oh boy, will you be surprised when you see billiard balls spooky communicating faster than light.

 

What someone seems to be forgetting is that billiard balls can't be in a superposition of spin states.

And if you give a pair of billiard balls opposite spins you know what their spins are; the big difference with entanglement is that it's really about the choice of measurement and in which direction. The entangled particles appear to "communicate" this information about direction of spin after being separated; the separation following entanglement and the choice of direction are an important part of the experiment.