Fun question RE: Bell's Theorem

In summary, Bell's inequality shows that a non-contextual hidden variable model is inconsistent with the experimentally-confirmed facts of quantum mechanics. The assumption that parameters exist whether they are measured or not is rejected by Bell's first theorem.
  • #36
RandallB said:
I take that “larger parameter space” as additional dimension(s), but however you care to define it, - it is Non-Local and has no bearing on ‘disproving’ Bell.
Rather so far Bell experiments provide support for such Non-Local ideas, QM, BM, MWI, and this one.

What could be more exciting that to have someone pull out the only experimental support for these Non-Local ideas by demonstrating Bell’s Logic as invalid?
My only problem with mw is he did not state a opinion, as requested in the OP, but his conclusion that “Thus: Bell's logic is wrong!
He has been asked by you and other of us enough – without giving some small foundation I’ll let him pass by as just another ‘Silly’ Crackpot.

I see you still don't understand the meaning of the word local, Randall-B. I quickly scanned the paper and it basically adresses the possibility of hidden correlations, this goes back to the Clauser Horne Shimony criticisms on Bell, and that is pretty old stuff.

As a general comment : one can point out (as I do) that Bell inequalities can be circumvented, a whole other problem is to make a theory which does so in a *natural* way (such thing is bound to be more complicated than QM).

Careful
 
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  • #37
Careful said:
I see you still don't understand the meaning of the word local, Randall-B. I quickly scanned the paper ...
Careful I see you still define “LOCAL” in your own terms without properly defining your use of the term.
I understand very well that BM, Strings, MWI and more can define “Local” in a manner that can solve most all the paradoxes resolved by the QM statistical HUP interpretation (Copenhagen).

BUT all those do so though an addition degree of freedom of movement/measurement beyond what we can observe in our perceived reality. That way we can apply one of these:
A) The separation between our event of interest and the observed result of that event at some distance, in some dimension unclear to us is a separation of ZERO. Thus within necessary limitations on information transfer, correlations & interference patterns can be obtained.
OR
B) By establishing an unknown influence in an alternate three dimensional reality overlaying our observed reality with the ability to propagate waves there that can provide some guidance to particles as the move in our realty, can amaze us with the resulting correlations & interference patterns.
C) Or some other combination of “local” actions within the definitions of a non-classical theory to resolve most paradoxes that cannot be resolved classicly.

Doing so with a new non-classical reality is fine – but not without making clear that is what you’re doing.

What I find endlessly tiring is the refusal by the proponents of these ideas is their unwillingness to properly identify what they mean by “LOCAL”! Because it requires using Multi-dimensional local, super-local, meta-local, Bohm-Local or (I don’t care what you cat it)-local version of it
And NONE of these are Einstein Classical Local and are all Classically and Bell Theorem Non-Local.
And yes the Bell Theorem can be and has been circumvented by many Non-Local ideas, just not a Local one.

Even Hess-Philipp called their model a “possible” loophole, see http://www.pnas.org/cgi/content/full/98/25/14224" .
If you quickly scan to the bottom, a citing article is clearly listed declaring “Hess-Philipp model is nonlocal”

So I do what Local is;
I also know what “non-local local” is, and I can tell when someone shortens that to just ‘local’ without explanation. Personally I find the omission of that detail unfairly misleading.
 
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  • #38
RandallB said:
Careful I see you still define “LOCAL” in your own terms without properly defining your use of the term.
I understand very well that BM, Strings, MWI and more can define “Local” in a manner that can solve most all the paradoxes resolved by the QM statistical HUP interpretation (Copenhagen).
.
I defined local for you plenty of times before, it is simply a field theory which satisfies the constraints of Lorentz covariance (with an arrow of time). These theories are not excluded by Bell, and basically Bell's definition of local is naive (as I said plenty of times too). Therefore, your use of non-local is an abuse and to refer to BM in this context is even more silly. BM is non local in the sense that its dynamics requires a hypersurface for it's definition (and is dependent upon the latter choice) in sharp conflict with the demand of Lorentz covariance.

Either you are going to scientifically attack my statement and definition or either you are going to learn something about locality. And please stop referring to rebuttals to papers, either you comment it yourself and then we can enter in an honest debate or either you don't comment at all. Science is not an opinion contest, and I am not interested in polls.

Careful
 
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  • #39
Careful said:
I defined local for you plenty of times before, it is simply a field theory ……..
I find you opinions and definitions to confusing follow. You complain when I don’t accept BM as local.
Therefore, your use of non-local is an abuse and to refer to BM in this context is even more silly.
But it only takes one more sentence and you say;
BM is non local in the sense that its …..And please stop referring to rebuttals to papers, ..
You mean the rebuttal listed at the bottom of the paper you were referring to?? Let me see if I have this right – read papers you read not those papers that disagree with papers you read. Just how does that fit with:
Science is not an opinion contest, and I am not interested in polls.
Is that unless they are your opinions? And why do you want to address polls I sure don't.

Bell desired to support the Einstein argument, that a Local hidden variable should account for what the HUP in QM could account for, and QM was an incomplete explanation without it that variable. His theorem was to help define that unknown hidden variable.
In the context of the experiments we are dealing with here, we have a pair entities; electrons with spin, or photons with polarization.
LOCAL is simple by design; it expects to define ALL the variables associated with each entity where were and when they created. Variables limited to that nearby Absolute Space and at that Absolute Time. To independently remain with each separate entity until disturbed no matter how far they separate. Simple and consistent with Newtonian concept of Absolute Space and Time even with Special Relativity.

The point of Aspect and other experiments is not to show directly that QM is correct and complete, but by the Bell Theorem that a classical solution using Absolute Space and Time cannot succeed and therefore imply that the QM/HUP could be true and complete and that a non-local solution is required.
But it cannot prove the QM/HUP part. Which is why we have so many custom made non-local solutions that can work and MIGHT be right.
For some reason many insist needing to call themselves “local”. However they do it: Enlarge “Local” to a local system that includes the separate A & B observation points. Use extra dimension(s) BM, String, MWI etc; Statically reach across time with field probabilities, uncertainty probabilities, etc for explaining groups of data; collapsing wave function concepts; and on and on.
All of these at best are new or Nuevo-Local, not Absolute Space and Time Local.
What I don’t get is why anyone thinks these theories gain credibility by claiming them to be local. None of these theories are EXCLUDED by Bell experiments, and claims to there own version of “local” doesn’t help science prove one version over another.

If you think you have found the solution that is truly a valid local realist explanation and therefore disqualifies all those Non-Local theories including those with "non-local local" explanations. It is really quite simple; clearly describe for us the hidden variable so that it is no longer an unknown hidden variable, in absolute space and time terms of course and in terms of just one pair of entities.
 
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  • #40
roundedge said:
If you're not familiar with Bell's inequality, and the subsequent experiment, I suggest perusing over http://www.upscale.utoronto.ca/GeneralInterest/Harrison/BellsTheorem/BellsTheorem.html"

1. the validity of logic

2. objective reality

3. locality

however the results of the experiment contradict the inequality.

Thus, by reducto ad absurdum, one or more of those three assumptions must be wrong.

Personally, I'd prefer to believe that we've somehow misconceptualized what spin is, or we've made a mistake in assuming that spin can be considered a quality, or that an electron can be considered an individual with individual qualities, than concede one of those three assumptions. However, if forced to bite the bullet, what assumption do you think would be the first to go.
Here is my current personal opinion:

The one to go would be: The validity of the logic used.
So objective reality and locality should stay.There is one weak point in Bell's logic. One thing which he can’t prove:

Bell type hidden variables are always inputs to random processes.
Two separate random processes together can never obey the conservation
laws. It is the a-priori assumption that these processes are random which
makes the Bell inequality fail.

The random process is typically a (polarizing) beamsplitter. The photon
must choose to leave the beamsplitter at either one way. The Bell hidden
variable assumes an A% chance for the photon to leave at one side and
a (100-A)% chance to leave it at the other side.

To obtain the experimental correlation results with a Local, Hidden Variable
model one has to assume that the Hidden Variable(s) predetermine the
side at which the photon will exit the beamsplitter. That would mean
that the apparent randomness is just our ignorance of what is physically
going on.Both Locallity and Objective Reality could be saved if we would make
the asumption that the randomness at the beamsplitters is our ignorance. Recent experiments show that there is more going on in a beamsplitter
as we were aware of until recently. One experiment for example shows
that two independent photons with an arbitrary phase relation entering
the beamsplitter at the same time will always leave the beamsplitter at
the same side! Both leave at one side or the both leave at the other
side but they will never leave the beamsplitter at different sides.

Both photons have the same polarization but apparently the randomness
assumed: A% vs (100-A)% is not longer valid for both photons.

See: Experimental interference of independent photons:
R. Kaltenbaek et al, PRL 96, 240502 (2006).
http://arxiv.org/abs/quant-ph/0603048
I have not seen any experiments yet with beamsplitters which take
into account the V,A potential components of the photon. Two
so-called "undistinguishable" photons with equal polarizations can have
their V,A components pointing in totally different directions. The V,A
components of a photon may be candidate hidden variables.Regards, Hans
 
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  • #41
Bell's theorem and ''the logic used''

Hans de Vries said:
Here is my current personal opinion:

The one to go would be: The validity of the logic used.
So objective reality and locality should stay.

Regards, Hans

Hans, I appreciate the clarity of your wording, and am happy to say that I share this part of your post as my opinion too.

In other words (if I understand you correctly): We question the validity of ''the logic used'' AND NOT the validity of formal logic in general.

I might add that many authors appear to drag their own strange (personal) logic into the issue, departing from Bell's own ''defective'' logic in the process. Thus, I've just had a look at the Harrison site http://www.upscale.utoronto.ca/PVB/H...lsTheorem.html and have to say that I've never seen such a mess. I hope you'll join in as I attempt to sort it out!

PS: I'll probably create a new thread: Bell's theorem: Harrison's (2006) inequality refuted.

wm
 
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  • #42
Bell's theorem and the fear of being shown up?

RandallB said:
Yes it is, they are essentially using a NON-Local description where additional information hidden from us is contained in a “larger parameter space”.
From their introduction:


I take that “larger parameter space” as additional dimension(s), but however you care to define it, - it is Non-Local and has no bearing on ‘disproving’ Bell.
Rather so far Bell experiments provide support for such Non-Local ideas, QM, BM, MWI, and this one.

What could be more exciting that to have someone pull out the only experimental support for these Non-Local ideas by demonstrating Bell’s Logic as invalid?
My only problem with wm [= edit] is he [= assumption] did not state an [edit] opinion, as requested in the OP, [edit] but his conclusion that “Thus: Bell's logic is wrong!
He has been asked by you and other of us enough – without giving some small foundation I’ll let him pass by as just another ‘Silly’ Crackpot.

RandallB; you seem to be big on claims and low on performance. I'm concerned such a ''style'' may not be conducive to what's ahead here. (Anyway, enough said.) So:

1. Please (again) show me the logic behind your claim that I did NOT ''state an opinion, as requested in the OP''. Here's my opinion (again), in more general words: The logic used in the derivation of all ''Bell theorems'' is invalid.

2. I note that, despite my absence, you still did not nominate a ''Bell theorem'' that you personally endorse. I hope you accept the example that has been given (Yes?); and that you'll not be one of those who, afraid of being wrong, chime in at the end saying: "Of course; I knew that!'' (So we'll consider that gambit closed from the start, OK?)

3. As for demonstrating ''the invalidity of the logic used in Bell theorems'' -- rest assured that I'm committed to giving it my best shot here. Though I note that the example chosen is one of the messiest I've seen; and so I hope you'll help me sort it out right from the start ... because I'm not confident that I'll interpret it wholly correctly in my early attempts at clarification (before rebuttal).

With best regards, wm xor, if you prefer, W (wrong) M (mostly)
 
  • #43
Bell's theorem: Clarifying Harrrison's (2006) assumptions

BoTemp said:
wm, I have a thought. You have stated that Bells logic is flawed. Please state how. Personally, I don't care if it's a published paper or whatever, a posting to this forum is fine with me; I'm interested in your thoughts. I believe http://www.upscale.utoronto.ca/PVB/Harrison/BellsTheorem/BellsTheorem.html
was posted on this thread somewhere; I can't find a fault in the logic. Perhaps you can help me out.

Dear BoTemp, thanks for the example you've chosen, though it has to be one of the untidiest that I've seen. Indeed, if you had not endorsed its logic, I would not have bothered with it.

Also, in my view, when teaching students, photons are easier to present, and more convincing re the (supposed) non-locality. And whilst my first thought was to give (with your agreement) the photon equivalent, I'll refrain from that consideration here (in the spirit of your request for help, as I see it; ie, students would surely be better off with the photon case).

On first reading, the logic error leaps out at me, so perhaps I misunderstand the implications of the related assumption. Also, there appears to be an implicit assumption that may be equally telling against the case presented. Would you therefore please clarify:

1a. Electrons have spin in a given direction even if we do not measure it.

I'm confused about ''the given direction''. If you give me an arbitrary electron, and I give the ''direction'', then are you saying that the electron will have spin in the given direction, even though not measured?

1b. Implicit assumption: The assumption of FAITHFUL MEASUREMENT.

This assumption appears to be in play. For I take it that, when we measure the spin of the above electron in the ''given direction'' (ie, the direction given by me), then you will say that we faithfully measure (and record) the spin that the electron actually had in that direction before this measurement?

Thus, in summary, are we dealing with 3 primary assumptions?

1a. Electrons have spin in a given direction even if we do not measure it.

1b. If we do measure the spin (in #1a) ''in the given direction'', then the result is a faithful reporting of the pre-existing spin in this direction.

2. Logic is valid.

3. Locality (per Einstein) holds.


Looking forward to your clarifying thoughts on the above. With thanks again, and best regards, wm
 
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  • #44
wm said:
1. Please (again) show me the logic behind your claim that I did NOT ''state an opinion, as requested in the OP''. Here's my opinion (again), in more general words: The logic used in the derivation of all ''Bell theorems'' is invalid.
Sure – the logic for that is easy – you didn’t sate an opinion you said
"Thus: Bell's logic is wrong! "
Your word “THUS” implies that based on SOMETHING you draw the CONCLUSION.
I was only asking for some detail on the “something’.
If you are withdrawing the implication that you had something to draw a conclusion from and were only stating a desire to show Bell’s logic wrong -- then fine you meant to say you were just getting started.
2. I note that, despite my absence, you still did not nominate a ''Bell theorem'' that you personally endorse.
As to personally endorsing A Bell theorem – I’m only aware of one, he didn’t create a list of variations. There are various non-local theories that explain the results of Bell Theorem experiments.

My personal expectation is that non-local theories are incomplete and a more complete solution is possible even while all three of the OP issues remain true. That makes me a Local Realist if that’s clear enough.

But until that is demonstrated, I accept the theory that rules as QM. Even though I am impressed by the BM ideas, mostly because of the thinking in Prince Louis de Broglie books, I’m biased by the clearly successful practical application of QM of the past several decades.
 
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  • #45
On the same wavelength.

RandallB said:
That makes me a Local Realist if that’s clear enough.

But until that is demonstrated, I accept the theory that rules as QM. Even though I am impressed by the BM ideas, mostly because of the thinking in Prince Louis de Broglie books, I’m biased by the clearly successful practical application of QM of the past several decades.

Thanks for this; for I see that we're making progress. I'm a Local Realist too, with local as in ''Einstein locality'' and realism needing more words than that (but it is not ''Einstein realism'' if we were somehow to believe that ''EPR elements of reality'' represent his views). (NB: He was dismissive of the EPR paper, which was mainly written by Podolsky.)

Anyway, as self-proclaimed Local Realists, many will put us in the same camp, they being convinced that we're both wrong, and even rather silly.

Now note: Being a Local Realist doesn't require me to negate the achievements of QM. It's just that I like my science to include some clarifications of reality as it is; if possible, independent of observation. So, difficult as that may be (and as impossible as some may claim it to be) I push on in the certain knowledge that ''only the impossible is impossible''.

Ciao, wm
 
  • #46
wm said:
. I'm a Local Realist too, with local as in ''Einstein locality'' ...
I am unaware of any Local Realist argument the claims:
"Bell's logic is wrong!"
I consider the Bell test the only one that has any chance of showing all non-local theories as incorrect or at least as no more than convenient analogies.
Fact is examination of experimental results so far indicate that Local Realists, such as myself, are likely incorrect and that a local hidden variable cannot provide good and that therefore reality is likely non-local.
Just because I disagree with non-local, I’ll not avoid it by accepting the idea the “"Bell's logic is wrong!" or question the validity of logic without some foundation. Certainly no foundation has been shown here.
I’d recommend you not accept as well, I don’t know how a local realist could.
 
  • #47
wm said:
Dear BoTemp

1a. Electrons have spin in a given direction even if we do not measure it.

1b. Implicit assumption: The assumption of FAITHFUL MEASUREMENT.

This assumption appears to be in play. For I take it that, when we measure the spin of the above electron in the ''given direction'' (ie, the direction given by me), then you will say that we faithfully measure (and record) the spin that the electron actually had in that direction before this measurement?
wm

I realize the example I gave wasn't the cleanest, but the logic is sound as far I could see. Anyway, the crux of the matter.

1a. Sloppy phrasing on the authors part. What he meant was "spin is conserved". The assumption is that measuring the spin at detector A tells you, without a doubt, the spin of the electron at detector B. You can't generalize this statement to any situation which doesn't have entanglement involved. I mentioned earlier that I'd entertain arguments that this isn't true, but those arguments would be refuting conservation of spin (angular momentum at a quantum level).

1b. Well, no, not really. Saying "the spin the electron actually had" is a fruitless question. Before measurement, the electron will have some wavefunction which is a superposition of the two spin possibilities. You assume that the measurement here is an ideal quantum measurement, and following from the postulates of QM you will observe either spin state with probabilities determined by the wavefunction. An ideal measurement collapses the wavefunction into one spin state, the one you observe. The implied assumption is that this ideal measurement is the only thing which affects the wavefunction of the particle.
 
  • #48
I could be wrong.

RandallB said:
I am unaware of any Local Realist argument the claims:
"Bell's logic is wrong!"
I consider the Bell test the only one that has any chance of showing all non-local theories as incorrect or at least as no more than convenient analogies.
Fact is examination of experimental results so far indicate that Local Realists, such as myself, are likely incorrect and that a local hidden variable cannot provide good and that therefore reality is likely non-local.
Just because I disagree with non-local, I’ll not avoid it by accepting the idea the “"Bell's logic is wrong!" or question the validity of logic without some foundation. Certainly no foundation has been shown here.
I’d recommend you not accept as well, I don’t know how a local realist could.

1. I'm in the middle of revising my website. It addresses these issues, so I'll let you know when it's up (hopefully in September -- I took on too much!).

2. To be clear: I'm committed to Local Realism (as a principle theory) and my site happily supports my claim that: Every Bell-theorem and every Bell-test-challenge (known to me) contains a logic error*. That is, I've so far found no need to waver from LR in that my LR derives all the ''entangled'' results (and I respond to all correspondence on my site).

3. In relation to such matters here, as captured in BoTemp's correspondence, I'm aiming to have a first draft up here by next Monday -- at the level of high-school math and logic.

* The most common logic error is the failure to distinguish between statistical-dependence P(AB|C) = P(A|C).P(B|AC) = P(B|C).P(A|BC) = P(BA|C) and statistical-independence P(AB|C) = P(A|C).P(B|C) = P(BA|C).

As always, I could be wrong, wm
 
  • #49
Debunking Harrison's (2006) inequality

BoTemp said:
I realize the example I gave wasn't the cleanest, but the logic is sound as far I could see. Anyway, the crux of the matter.

1a. Sloppy phrasing on the authors part. What he meant was "spin is conserved". The assumption is that measuring the spin at detector A tells you, without a doubt, the spin of the electron at detector B. You can't generalize this statement to any situation which doesn't have entanglement involved. I mentioned earlier that I'd entertain arguments that this isn't true, but those arguments would be refuting conservation of spin (angular momentum at a quantum level).

1b. Well, no, not really. Saying "the spin the electron actually had" is a fruitless question. Before measurement, the electron will have some wavefunction which is a superposition of the two spin possibilities. You assume that the measurement here is an ideal quantum measurement, and following from the postulates of QM you will observe either spin state with probabilities determined by the wavefunction. An ideal measurement collapses the wavefunction into one spin state, the one you observe. The implied assumption is that this ideal measurement is the only thing which affects the wavefunction of the particle.

Thanks for this; we pretty much agree. I found the sloppy phrasing surprising and off-putting. I hoped that you and I had a common view of what we can say about an electron. BECAUSE I didn't want to address such side-show issues in my first draft -- which should be here by Monday -- at the level of high-school math and logic
 
  • #50
Administrative fix of thread-heading please??

NB: Students searching for Bell's THEOREM

might miss this thread

if the header-spelling is left as Bell's THEORUM [sic].:cry:

Can it be corrected, please? (Separate email sent to Admin last week.)

Thanks, wm:smile:
 
  • #51
I think this is about time that I will refer all of you again back to the PF Guidelines that you have explicitly agreed to. Take note, for instance, that the main forum is NOT the place to do an exercise in one's own personal theory, no matter how convincing one thinks it is.

If you have a theory that contradicts or question currently accepted physics, and you have not published it already in a peer-reviewed journal, the only place on here that you can air out your ideas is the Independent Research forum, as has been clearly described in the guidelines. I believe that we have been more than generous (and patient) in letting this thread go on as long as it did considering the content.

If any of you have anything substantially new to add to the original issue in this thread, please contact me and I'll reopen it. If not, this topic has ran its course.

Zz.
 

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