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Why is superdeterminism not the universally accepted explanation of nonlocality?

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Demystifier
#163
Mar1-12, 03:54 AM
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Thanks lugita!
jadrian
#164
Mar1-12, 04:12 AM
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Quote Quote by jadrian View Post
let me clarify this a little bit. the "conspiracy" is simply the result of the history of the causal interactions of ALL the stuff in the universe. it is a result of d and a being the part of the sum of everything in the universe. d and a alone would not be able to affect eachother if isolated from the history of all interactions in the universes past. it requires all the information in the universe to result in determinism. there is nothing super about it.

if determinism only is effective within lightcones, in which case if outside eachothers lightcones, a and d could not affect eachother just as future events cannot effect the past, as lightcones expand at the speed of light, if there were particle a that had not yet interacted with other particles d1 d2 d-infinity, (i stated before that this should be impossible under a causally governed universe) in this hypothetical case it would be not practically, but THEORETICALLY impossible to do such an experiment or have such nonlocal effects even without an experiment. also, along with photons a and b traveling in opposite directions, so too will plenty of other EFFECTUAL information be propagated to a and d from particles locally and causally effecting the photon source, so it would make a and d effectively the same as being locally deterministic. it would be determined tho in the universe that the lightcones would eventually expand to make a and d react causally therefore deterministically.
but outside our lightcone they will have their own lightcone, in which their determinism will eventually mesh precicely with our determinism leading to the same result that the future of everything is predetermined.
Delta Kilo
#165
Mar1-12, 08:55 AM
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Wouldn't retro-casuality have exactly the same outward appearance as superdeterminism to us? It is certainly more economical (in occam sense) - the 'conspiracy' in each case only has to go back in time as far as needed to achieve correct outcomes as opposed to setting it all up just before big bang. Also laws of physics are time-symmetrical already (:those that counts anyway:).
DrChinese
#166
Mar1-12, 08:56 AM
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Quote Quote by jadrian View Post
if determinism only is effective within lightcones, in which case if outside eachothers lightcones, a and d could not affect eachother just as future events cannot effect the past, as lightcones expand at the speed of light, if there were particle a that had not yet interacted with other particles d1 d2 d-infinity, (i stated before that this should be impossible under a causally governed universe) in this hypothetical case it would be not practically, but THEORETICALLY impossible to do such an experiment or have such nonlocal effects even without an experiment. also, along with photons a and b traveling in opposite directions, so too will plenty of other EFFECTUAL information be propagated to a and d from particles locally and causally effecting the photon source, so it would make a and d effectively the same as being locally deterministic. it would be determined tho in the universe that the lightcones would eventually expand to make a and d react causally therefore deterministically.
Not sure what most of this means, but would like to remind you that a and d have never existed within a common light cone. They were "born" separated and remain separated their entire existence. Yet they were made to be entangled, displaying correlations characteristic of twins. Yet other photons from the same laser sources at the same time, those not made to be entangled, show no such relationship. Further, the decision to entangle is made AFTER the photons are detected and their existence has ended.

And you are trying to say that local deterministic systems naturally display this behavior. You might want to rethink that. Clearly, you need something "super" to explain this. Because your explanation above doesn't explain why some photons show the correlations and others don't. Following your concepts, all of them should evidence Bell state statistics.
lugita15
#167
Mar1-12, 09:40 AM
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Quote Quote by DrChinese View Post
And you are trying to say that local deterministic systems naturally display this behavior. You might want to rethink that. Clearly, you need something "super" to explain this. Because your explanation above doesn't explain why some photons show the correlations and others don't. Following your concepts, all of them should evidence Bell state statistics.
DrChinese, you're not a very good conspiracy theorist. Clearly the particles are always entangled with each other, but never display this entanglement unless they know that quantum mechanics would consider them to be entangled, in which case they would each try to act in exactly the right way so that everyone is fooled into thinking quantum mechanics is right. Theories are so easy to make when you abandon things like Occam's razor.
DrChinese
#168
Mar1-12, 10:09 AM
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Quote Quote by lugita15 View Post
DrChinese, you're not a very good conspiracy theorist. Clearly the particles are always entangled with each other, but never display this entanglement unless they know that quantum mechanics would consider them to be entangled, in which case they would each try to act in exactly the right way so that everyone is fooled into thinking quantum mechanics is right. Theories are so easy to make when you abandon things like Occam's razor.
I was trying (unsuccessfully it seems ) to force jadrian to realize that the laser source must be imparting the hidden (it is a conspiracy, so something should be hidden) information to the photon at the time it is created. But that the same laser source only imparts the correct information for perfect correlations to a small subset of photons, just those that some spacelike-separated robotic observer will eventually mark as being in a Bell state (and no others).

So that means the laser source ALSO knows enough about that robotic observer to know which ones will be seen to be entangled (since the robotic observer makes that decision at a later time).

Oh, and the laser source ALSO knows which direction the polarizers for a and d are set in. That, of course, so that the Bell relationship holds. Of course, those polarizers can be set by 2 more robotic observers using let's say, 2 different random algorithms. Which of course the laser source knows this too.

Of course, there are actually 2 separate laser sources which are phase locked together. So both knows what the other is going to do. On the other hand, the photons don't even need to exist at the same time any more than they need to exist in the same location, so that the appearance of entanglement crosses both space and time if we want to set it up that way.

And so, as you say, does the theory continue on without the benefit of Occam...
zonde
#169
Mar1-12, 11:03 PM
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Quote Quote by lugita15 View Post
You're right, I am assuming that. But that's a harmless assumption to make.
Linear relationship between θ and correlation level follows directly from that assumption.
So your statement that "the argument does not assume it, it proves it." ... well, I wouldn't say it's very truthful.

Quote Quote by lugita15 View Post
Perfect correlations for matching measurement settings is a consequence of quantum mechanics, so surely if a local realist theory wanted to match the predictions of QM then it would have to have perfect correlations for matching measurement settings. I highly doubt this is what ThomasT is disputing.
Local realistic theory can not reproduce all predictions of QM.

But local realistic theory can try to reproduce QM predictions in domain where they are experimentally verified. And that domain does not include (something close to) perfect correlations for matching measurement settings.

What I think ThomasT is disputing is that given Malus law it is very unreasonable conclusion that there is linear relationship between θ and correlation level.


Quote Quote by lugita15 View Post
(You can, of course, be the fringe type of local realist who has a theory making predictions contrary to QM, but who believes that the only reason the experiments have proven QM right is that they're subject to various flaws, loopholes, and systematic biases. But as Bell tests become more sophisticated, that becomes an increasingly untenable positon, arguably even more so than superdeterminism.)
No, I am a type of local realist who tries to make falsifiable local realistic explanations agreeing with QM in a domain where it is experimentally tested.
lugita15
#170
Mar1-12, 11:47 PM
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Quote Quote by zonde View Post
Linear relationship between θ and correlation level follows directly from that assumption.
You're right, it's a fairly direct route from the assumption that there is perfect correlation at identical polarizer settings to the conclusion that the local realist must believe that the correlation is linear. But ThomasT does not agree with this fairly direct line of reasoning, so I'm trying to convince him that it works.
Local realistic theory can not reproduce all predictions of QM.
If I could persuade ThomasT of this, I'd be done.
But local realistic theory can try to reproduce QM predictions in domain where they are experimentally verified. And that domain does not include (something close to) perfect correlations for matching measurement settings.
But that just has to do with practical experimental limitations. The point I'm arguing with him about is whether someone can believe that all the predictions of quantum mechanics are correct and still believe in (non-superdeterministic) local realism. I'm trying to show that the answer is no, because one experimental prediction of QM is perfect correlations at identical polarizer settings, from which the local realist is forced to believe in a linear correlation relationship, which is in contradiction with another experimental prediction of QM.
What I think ThomasT is disputing is that given Malus law it is very unreasonable conclusion that there is linear relationship between θ and correlation level.
I agree that this is the point of contention, but keep in mind that he thinks a local realist can believe in the nonlinear correlation given by Malus' law, while at the same time also believing that there is perfect correlation at identical settings. I hope you agree that he's wrong on this point.
No, I am a type of local realist who tries to make falsifiable local realistic explanations agreeing with QM in a domain where it is experimentally tested.
Out of curiosity, which experimental loophole of Bell tests do you cling onto? Detector efficiency, communication, freedom of choice, or something else?
jadrian
#171
Mar2-12, 07:30 AM
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Quote Quote by Delta Kilo View Post
Wouldn't retro-casuality have exactly the same outward appearance as superdeterminism to us? It is certainly more economical (in occam sense) - the 'conspiracy' in each case only has to go back in time as far as needed to achieve correct outcomes as opposed to setting it all up just before big bang. Also laws of physics are time-symmetrical already (:those that counts anyway:).
exactly. it shouldnt be called super determinism. it should be called universal causality. if im the first with this this then i claim it. adrians universal causality
jadrian
#172
Mar2-12, 07:33 AM
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Quote Quote by lugita15 View Post
You're right, I am assuming that. But that's a harmless assumption to make. Perfect correlations for matching measurement settings is a consequence of quantum mechanics, so surely if a local realist theory wanted to match the predictions of QM then it would have to have perfect correlations for matching measurement settings. I highly doubt this is what ThomasT is disputing.

(You can, of course, be the fringe type of local realist who has a theory making predictions contrary to QM, but who believes that the only reason the experiments have proven QM right is that they're subject to various flaws, loopholes, and systematic biases. But as Bell tests become more sophisticated, that becomes an increasingly untenable positon, arguably even more so than superdeterminism.)
if you could match experimental settings, which you cant, then you wouldnt have correlations, youu would have the exact same result.
jadrian
#173
Mar2-12, 08:02 AM
P: 143
Quote Quote by lugita15 View Post
OK, let me give you an example of why you need special initial conditions.

In a deterministic theory, in order to predict the current behavior of any object, you need to know the initial conditions of the object, as well as the deterministic laws of the universe. In Newtonian mechanics, for example, you need to know the positions and velocities of all the particles at time t=0, and then F=ma will tell you the behavior of the particles at all later times.

Now let's consider what a local deterministic explanation of entanglement would look like. Let particles A and B be an entangled pair of photons, which are separated by a great distance and then sent through polarization detectors. We also have particles C and D: C tells the experimenter what angle he should set the polarizer that measures A, and D tells the experimenter how to set the polarizer that measures B. You can think of C and D as neurons in the brains of the experimenters if you like.

Now we find experimentally that the behavior of particle A through its measurement device is strongly correlated with the angle at which B's measurement device is set. And that angle is determined by particle D. So we have a correlation between the behavior of particles A and D.

But particles A and D are seperated by such a large distance, so they cannot communicate with each other to coordinate their behavior (unless you have a nonlocal theory like Bohmian mechanics which allow undetectable faster-than-light signalling between particles). So a local determinist has to conclude that A and D are correlated not based on a current relationship between the present states of A and D, which would be impossible, but based on a past relationship of the initial states of A and D.

This is what we mean by special initial conditions: A and D seemingly have nothing to do with each other. After all, it is A and B that were in the entangled state, and yet somehow we have to conclude that the initial conditions of A and D had to be specially set so that a correlation between A and D would be observed in the future. And instead of just D, we can have a large number of particles D1, D2, D3,... which together determine the measurement setting, so the initial state of particle A had to have been set based on the initial states of all these particles. And in the real world, almost all particles in the universe are interacting in some way with almost all other particles, so really the setting of measurement device depends on almost everything in the universe, from which we conclude that the initial conditions of the whole universe were specially set so that the right kind of correlation would be displayed billions of years later between particle A and the measuring device.

This is why superdeterminism is called "conspiratorial". That doesn't mean it's wrong, it just has some issues which make it rather difficult to construct a viable superdeterministic theory, but let me repeat that some potential first steps toward such a theory have already been taken by a few people.
also with d could have this instantaneous effect on a as i could decide to shoot my self in the head or not depending on the angle, wouldnt this be faster than light info tranfer, violating relativity?

this further seems proof that d and are within the lightcone of the distant past, in which case, the info about what d will do to affect a is predetermined. and nonlocal interactions can only occur within a lightcone or you violate relativity.
jadrian
#174
Mar2-12, 08:07 AM
P: 143
also, has it been proven in a lab that time moves forward and isnt frozen or moving backwards? it seems like that is something our intuition has guided us to regard as truth. is there not enough intuition in the world to regard determinism as truth?
jadrian
#175
Mar2-12, 08:23 AM
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Quote Quote by DrChinese View Post
Free will is not a necessary component of QM. So I certainly am not rejecting superdeterminism because of that. I reject superdeterminism as an explanation for Bell test results, and I do so for the reasons already stated.

Please bear in mind that there are no candidate superdeterministic theories to reject at this point, so it is a moot point in many ways. The reason I mention the amount of local information to be stored in every particle is because a candidate theory will end up postulating this (in some form or fashion) as a way to explain Bell test results. It is not necessary to assume free choice for measurement settings in any stage of the argument, but you must explain how (i.e. the exact mechanism, since we have no other reason to suspect it exists) the choice is propagated in a superdeterministic candidate.

Not so easy, I assure you. Which is again, the answer to your original question.


then why even call it superdeterminism. there is no conpiracy! its simply causality governed by relativity. call it universal causality. yes it is that easy.
Delta Kilo
#176
Mar2-12, 08:44 AM
P: 273
Quote Quote by jadrian View Post
exactly. it should be called super determinism. it should be called universal causality.
No, it is obviously different. superdeterminism does not by itself imply retro-causality. Instead some constraints are placed on the initial conditions which somehow pre-determine the outcomes of all Bell-type experiments (including experimenters' choices) in the future. These initial conditions then evolve forward in time according to laws of physics, causing all these pre-determined outcomes to eventuate.

And the other way around, retro-causality does not mean total super-determinism.
Quote Quote by jadrian View Post
if im the first with this this then i claim it. adrians universal causality
Too bad, you are at least 25 years late. See Transactional Interpretation. Although I personally don't like it, or rather don't see a point. It does not clarify what measurement apparatus is, where does preferred basis come from and what happens to Shroedinger's cat. It keeps all these thorny questions swept under the carpet.

But then transactional interpretation does not hold a monopoly on advanced wave solutions. After all, MWI is sufficiently weird, those who accept it might as well go for broke and add retro-causality to the mix.
jadrian
#177
Mar2-12, 08:53 AM
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Quote Quote by DrChinese View Post
That is just NOT true in any meaningful sense. A particle has only a few observable elements: momentum, position, mass, charge, spin, color, etc. It would be instructive to state specifically how you would know ANY information about the past interactions by knowing these. Suppose the spin is +1. What does that tell you? Or momentum is 1.63 (units ignored) in direction XYZ? Not much history to be gained from that!

No, you need there to be a rich hidden internal structure. One that contains the entire initial conditions of the universe, like DNA. And this DNA would need to be in every particle so they know how to react during Bell tests.
conservation of information. finiteness of information. your quote "what does that tell you" is ambiguous. you are trying to say that information can not adequately explain the universes deterministic evolution? are you serious? do you believe in true randomeness? in order for an electrons position to be truly random, you would have to assume it is moving at infinite speed!

and your dna analogy is completely imcompatable. dna is replicated. information is not.

consider a rack of pool balls getting struck by the cue ball.
now remove all the balls besides the cue ball and the 8 ball. assume the cue ball is particle d and the 8 ball is particle a. without the other balls measured positions on the table, you will not be able to know how the cue ball transfered its info into the 8 ball resulting in the cue ball and 8balls new locations. it requires ALL!!, ALL!! how many times do i have to say it? of the information of all the other balls location, how much they spun, etc.. to figure out how cause led to effect via determinism in this situation. you keep throwing these things at me as if they are a way around the law of conservation of information. seriously?
DrChinese
#178
Mar2-12, 08:56 AM
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Quote Quote by jadrian View Post
also, has it been proven in a lab that time moves forward and isnt frozen or moving backwards? it seems like that is something our intuition has guided us to regard as truth. is there not enough intuition in the world to regard determinism as truth?
Actually, there are QM interpretations in which time does not flow in the conventional sense. These are called "block world". I happen to be something of a fan of a particular one of these, called Relational Block World.

Relational Blockworld: A Path Integral Based Interpretation of Quantum Field Theory; W.M. Stuckey, Michael Silberstein, Timothy McDevitt (2009)

Although time does not flow, the future is a component in interactions and it is the total setup that is relevant. Although the authors do not call it a time symmetric model per se, I think it qualifies.

For those that are interested:

The above paper is advanced reading, but it is absolutely fascinating in this sense: It is a QM interpretation that makes predictions that are slightly DIFFERENT than standard QM. Incredibly, those predictions seem to account for experimental evidence in favor of an accelerating expansion of the universe WITHOUT adding otherwise new physics.

Easily the most ambitious program I have seen in the few years. So a tip of the hat to the authors, good luck! If anyone wants to discuss, we can start a new thread on that.
jadrian
#179
Mar2-12, 09:02 AM
P: 143
Quote Quote by lugita15 View Post
Again, I am not claiming that A and D could never have interacted. I am saying that the interaction of A and D would have to have occurred in just the right way so that they would demonstrate nonlocal correlations of just the right kind. And by similar arguments, you would have to conclude that at the beginning of the universe all the particles interacted with each other to set just the right initial states for each particle, so that all the Bell tests which would be performed in the entire history of the universe would get just the right results. That's what's called a conspiracy.
they dont have to interact in a special way, what makes you think that. weve already been through your abcd experiment and ive shown its irrellevant to universal causality leading to determinism without any special initial conditions. there is no conspiracy unless you NEGLECT the histories of the pool balls besides the cue ball and 8 ball as i described above
DrChinese
#180
Mar2-12, 09:15 AM
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Quote Quote by jadrian View Post
conservation of information. finiteness of information.... you keep throwing these things at me as if they are a way around the law of conservation of information. seriously?
Well, golly. Perhaps you can share this with us. What exactly is this law? Can you cite a reference? Does it have anything to do with entropy (which increases to the future, see 2nd law of thermodynamics)?

At any rate, you continue to throw out terms without understanding their meaning. At this point, I, lugita15. Delta Kilo and others have tried to help you with the physics involved. You seem to reject this in favor of speculation which lacks any basic background study or consideration. Your billiard ball example is typical, as it doesn't explain Bell test results and never will.

So good luck, and again I recommend you do some more study in the area.


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