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

[DevilsAvocado]

EPR requires some further constraints as follows:
1) The LHV's can't be singular objects, but rather local ensembles, roughly analogous to what any classical waveform is.
2) The properties, presumed non-local, can't be an absolute observer independent character of the ensemble. Rather a property relative to an observer, the experimental apparatus in this case. This is why I said the fact that EPR correlations are frame dependent lends support to this view, and linked papers to demonstrate.
With these two conditions, Bell's theorem is silent. It neither proves it right or wrong, unlike the marbles.

I’m going to give you my layman assumption why I believe LHV is a dead parrot.

Please feel free to correct me (if and when I’m wrong):

• YES, it’s impossible to make any distinction whatsoever between LHV and QM predictions on a singular object/particle/photon, and that’s why Einstein & Bohr had the long and unresolved EPR-debate.
  
  
• In 1964 John Bell introduces the brilliant idea to enforce probability into the measurement of EPR, to be able to distinguish LHV from QM predictions. John Bell implements this in the form of varying the angles of the analyzers.
  
  
• There is still no way to calculate QM probability on a single entangled pair of photons.
  
  
• Today’s technique allows us to "http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.2529v2.pdf" ". Meaning – we can send one pair of entangled photons at a time and measure the outcome.
  
  
• There is no need to 'speed up' the excitation of entangled photon pairs to get an analogy to a "classical waveform". There could be one year between every pair – and the QM predictions are still there (in the same way as Double-slit electron diffraction*).
  
  
• Some argue that the entangled pair is disturbed by environment and is impossible to measure with any accuracy. This is somewhat true; there is noise which disturbs the system. However the use of http://en.wikipedia.org/wiki/Coincidence_counting_(physics)" is "improving the signal to noise ratio to the extent that the quantum behavior can be studied, without removing the noise completely".
  
  
• With the described conditions above, we can send 100 pairs of entangled photons towards the polarizer’s which are RANDOMLY ALIGNED AFTER THE ENTANGLED PAIR LEFT THE SOURCE, where the polarizer’s are http://arxiv.org/abs/0803.2425" . Meaning – there is absolutely NO WAY for the entangled pair to AGREE on the outcome since they are outside each other’s light cone when the parameters for the experiment are finally settled.
  
  
• QM predictions stipulate that if we send 100 entangled pairs of photons and the angle of the polarizer is 22.5°, we should get a correlation of 0.71, meaning 71 pairs are correlated (+,+) and 29 pairs are non-correlated (+,-) (-,+). And this is exactly what happens – EVERY TIME in thousands of performed experiments. And there is NO WAY for LHV to even get close to the QM 0.71 correlation, LHV always gives a 0.5 correlation.
  
  
• To argue that noise is by chance creating this seemingly correlation – is not healthy science.
  
  
• To argue that defective optics in crystals is by chance creating this seemingly correlation – is not healthy science.
  
  
• To argue that there is an interpretation (which has not yet been confirmed) who makes everything a non-issue – is (maybe) not healthy science.

This is why I believe: Local Hidden Variable Theory = Norwegian Blue Parrot


Double-slit electron diffraction*
https://www.youtube.com/watch?v=<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/FCoiyhC30bc&hl=en_US&fs=1&rel=0&color1=0x006699&color2=0x54abd6"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/FCoiyhC30bc&hl=en_US&fs=1&rel=0&color1=0x006699&color2=0x54abd6" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>

If the relational interpretation holds, then it makes no difference what reference frame they are in. The measurements don't make the choice, they merely finalize them.

AFAICT this makes the "Norwegian Blue Parrot" moving a little again...

You can compress and stretch them, or even time for an individual, but event ordering remains the same. If this was possible you could use a pair of moving known frames to measure the distance to various stars, but it's not. Yet if a faster than light mechanism actually existed you could. EPR doesn't 'effectively' work to allow changing real event ordering either, which lends to the relational interpretation. Yes, I would be the lawyer.

It’s possible I have misunderstood the 'problem' of RoS & EPR, but if we for awhile pretend that LHV is a working solution, then it would all be a question of 'good old relativity'. Your example with "all bullets in one gun without knowing which" is as good as any EPR setup – it’s a question of a random value that we yet don’t know.

BUT according to all I have said so far – the outcome is settled at the measurement and are instantaneously effecting to outcome of the entangled partner.

Thus in one observer's reference frame Alice would physically causing Bob’s death, and in the other observer's reference frame Alice would be completely innocent.

I do think that would cause some trouble for you as 'the lawyer'.

 

[ThomasT]

Again, no. In a local hidden variable model, each observer is measuring a separate reality. So there is no JOINT observable (or context).

Right. But the joint, entangled situation requires a joint observable and a joint measurement parameter. So, do you see why lhv theories must be ruled out and why that doesn't tell us anything about Nature?

If there is a "joint detection parameter" observable, it is global. That does not work in a local world either. So you may be correct, but you are not describing a local realistic model.

I'm not trying to describe a local realist model. I'm trying to explain why a viable local realist model of entanglement can't be done.

 

[my_wan]

Ok, the reason I got rather insistent was due to the unqualified claim that Bell's theorem proves that local realism is untenable. I take this kind of statement in the general sense, irrespective of semantics. The following quote calls this into question. I'll outline my reading of Rovelli, so perhaps we can clear the undefined issues.

Rovelli's interpretation is generally considered to be acceptable, i.e. it is not local realistic. Therefore it follows Bell.

Pedantically , "not local realistic" does not in itself entail consistency with Bell. Only consistency with empirical detection statistics does that. But more importantly, Relational EPR is local and the realism has been weakened in the interpretation, not removed. Does this justify the position that Relational EPR is not locally realistic? This is strongly dependent on how the realism has been weakened, so we'll look at that a bit closer.

http://arxiv.org/abs/quant-ph/9609002"
It should be noted the RQM is formulated as an "information theory", rather than a physical theory. This is justified by the fact that what we measure are events rather than things. These events must also involve the observer, measuring device, which is itself an ensemble of events, to have any empirical meaning. The classical notion of observation, without non-trivially interacting with the system being measured, is untenable. The notion of an object in front of you that doesn't interact with the Universe in general is empirically moot. Thus reality in the empirical regime is a verb, rather than a noun. An ensemble of verbs at that. RQM does not speak of unmeasured variables, because that includes information not available in an information theory. Neither does it claim this unavailable information is not fully contained in the local ensemble being measured. That requires the assumption that what is unknown is non-existent, which exceeds the scope of the information available.

Weakening Realism
Also very important is the notion of "observer-independent values of physical quantities". By describing reality solely in terms of verbs, Bell's theorem is sidestepped, because Bell's theorem presumes spin state is a noun, or at least has a one to one ontological correspondence with a noun (lhv). If it is a 'relative' value of an ensemble (system verbs) wrt another ensemble (observer verbs) then an absolute spin state, assumed by Bell, is untenable, at least wrt the empirical information. As a theory of information, counterfactual reasoning is not strictly valid, and obtaining information via an interaction does not entail obtaining information not already present in the local ensemble. In the words of Rovelli:

http://arxiv.org/abs/quant-ph/0604064)]From[/PLAIN] the relational perspective the Heisenberg picture appears far more natural: \psi codes the information that can be extracted from past interactions and has no explicit dependence on time; it is adjusted only as a result of an interaction, namely as a result of a new quantum event relative to the observer. If physical reality is the set of these bipartite interactions, and nothing else, our description of dynamics by means of relative states should better mirror this fact: discrete changes of the relative state, when information is updated, and nothing else. What evolves with time are the operators, whose expectation values code the time-dependent probabilities that can be computer on the basis of past quantum events.

Thus, realism is in fact fully maintained in Relational EPR, in the form of verbs rather than nouns, and no mechanism is required to transfer information, at the time of the measurement, from space like separated regions. The information is fully contained in local events (verbs). The distance between such ensembles, and RoS, is then a moot issue.

Strengthening Realism
What is not provided by RQM are noun predicates that define the events (verbs). This is justifiable, even if they exist, given that any ontic entity, which does not interact with the Universe, lacks any empirical relevance whatsoever. Our experience of the world is fully and exhaustively defined by these verbs (events). Yet if Einstein realism holds, at least in principle, it must be in terms of nouns on which the verbs are relativistically predicated. Such attempts are often constructed as generalized thermodynamic models. The one I referenced previously in this thread actually constructed such EPR correlations from thermodynamic ensembles, among other things. The only response I got from that was that the reference was already known.

Summation
Although Relational EPR weakens Einstein realism in an empirical sense, it does not remove it in principle. Nor is the events themselves, void of any noun predicates, anything other than empirically real events, which requires no space like separated detection of events. It is only by assuming that a lack of information entails the lack of a relativistic properties that evidence of FTL can be constructed. I'm therefore inclined to say:
1) Relational EPR is a local realistic interpretation, with the caveat that the relative 'events' are real irrespective of lacking noun predicates or observer independent variables.
2) Local realistic models can, at least in principle, be formulated consonant with Bell and Relational EPR, with the caveat being that the empirical content is contained in the form of relativistic (observer characterized) verbs.
3) Bell's theorem fails to rule out lhv models in which observables are relativistic observer dependent characterizations of an ensemble of verbs.

 

[DevilsAvocado]

In particular what can be addressed in the general sense is this paper:
http://arxiv.org/abs/quant-ph/0604064"

Eureka! I think I got it (somewhat)!
Since we know there can’t be a global universal NOW (RoS), there can’t be a global universal REALITY (for all observers), right!?


http://arxiv.org/PS_cache/quant-ph/pdf/0604/0604064v3.pdf" is a cool paper!


And I must read it many times more to digest all. Rather 'shockingly' there seems to be parallels to what I was asking about in https://www.physicsforums.com/showpost.php?p=2716407&postcount=324", and the question of a wavefunction that collapses 'twice'.

An indication of this fact is in the well-known difficulty of describing and interpreting the relativistic transformation law of the wave function, when measurements involve observers in relative motion.

Relational EPR is very cool in the sense that it tries to 'merge' GR & QM by a 'slight' modification of both interpretations of Einstein & Bohr, smart and very 'diplomatic'.

I guess my 'rant' in https://www.physicsforums.com/showpost.php?p=2717199&postcount=331" is completely obsolete in the view of Relational EPR... sorry.


It looks like even DrChinese is out on thin ice...?

We call locality the principle demanding that two spatially separated events cannot have instantaneous mutual influence. We will argue that this is not contradicted by EPR type correlations, if we take the relational perspective on quantum mechanics.

Locality is at the very roots of RQM, in the observation that different observers (in general distant from one another) can have different descriptions of the same system.

I must digest and read again, but I shall return. Thanks for the link.


[PLAIN]http://upload.wikimedia.org/wikipedia/en/thumb/b/b0/Observer-observed.gif/350px-Observer-observed.gif
Observer O measures the state of the quantum system S

 

[my_wan]

Well speaking for myself, and continuing the "bull in the china-shop" method of scientific argument (although crude, it does create a clear path), I simply don't see why anyone would prefer pleading to alternative wholesale interpretations of reality rather than accepting some rather straightforward adjuncts to the classical reality we already know and love so well.

Yes, I seek as few adjuncts to classical physics as possible. What I hope to have made clear, unless someone can provide a good counterargument, is that, at least in principle, it's possible to maintain both locality and realism. If someone can posit a rational FTL mechanism, that's empirically useful, I'll accept that as a local mechanism. The speed C is the limit of locality as we know because that's what it defines given our present understanding, not because it is, if faster effects exist. However, simply as a method of sweeping EPR under a rug is not a valid justification in my view.

EPR fails and shows we need an additional (or alternative) model to explain the observations of quantum theory. Well, since what fails is local classical causality, why not just accept that there's a mechanism that allows non-local causality? As long as the mechanism is consistent with other classical observations everything's sweet, n'est-ce pas?

Ok, perhaps so, but before that can be stated without equivocation, the objections I have articulated must be addressed. Merely stating it is so does not make it so. As for my reasons for avoiding non-local effects: Because the conceptual and mathematical nightmare it creates in trying to get it to coexist with what we know is beyond belief. Even QM presently is a tame beast in comparison. If it remains "consistent with other classical observations" then it must lack empirical meaning, outside of sweeping conceptual issues under the rug. The constraints of RoS are quiet severe.

To be consistent with classical physics, the non-local causal mechanism can't be observable classically (obviously), so let's just chuck in a non-classical space using your favourite topological construct and propose that communication occurs in that space.

Some of my own modeling attempts explicitly allow certain variables of sorts to randomly exceed C. Yet it's unworkable as an EPR mechanism, or any FTL summation. So I'm not adverse to FTL mechanisms as such, but merely to poke it in like some surgical instrument accidentally sewed into your body by a surgical doctor doesn't cut the mustard for me.

That also conveniently allows us to have a real wave-function, consisting of the non-classical signal's effects on classical space at the instersection points of the topology with classical space.

FTL is not a requirement for real wavefunctions. It does seem require a separation, at least in principle, between the waveform (itself an ensemble), and the ensemble imposed by on it solely by limitations of specific knowledge of that ensemble.

That also allows us to suggest this is the space in which our consciousness exists, and clears up the mind-body duality to boot! (Evolution sussed out how to sustain consciousness in material bodys without much trouble, so it must be constructed from something that pervades the environment)

Ouch, I don't have a problem with the mind/body connection. I can even provide an empirically realistic self organizing 'toy' mind model, including memory, qualia, and evolutionary stages, with nothing more than metronomes and springs. Mathematically it's not really fundamentally new, but makes it easy to visualize how it leads to the empirical data. I generally find this kind of question involves the composition fallacy, and a failure to appreciate the nature and ubiquity of emergent properties. For this reason I find it interesting, but outside the scope here.

Then all we need, is some quantitative predictions from the model, such as delayed entanglement propagation, which we then observe.

Perhaps even something that''ll fill the holes left by Bell's theorem.

There, that's much more reasonable than relational interpretrations of reality and other such malarky. :)

I suspect that in labeling it "malarky" it's being interpreted within a singular myopic ontology. It was intentionally restricted in terms of an "information theory" for empirical and model independent consistency. Read my last response to DrC and I included at least one ontological model extension. If I took it as a final answer to the issues posed by QM, which I don't accept without GR, it would in fact be at the very least pointless. Understand what actually makes it work, and it gives you tools to think about real models, rather than just boring interpretations.

The most fundamental point I'm trying to make here is that, contrary to common opinion, EPR correlations don't entirely rules out all locally realistic theories. I've also provide the caveats that such models would require. I still have some interesting points to articulate for DevilsAvocado's last post. I look forward to defeat, if that is the truth, but the points actually need addressed for that to happen.

 

[RUTA]

Summation
Although Relational EPR weakens Einstein realism in an empirical sense, it does not remove it in principle. Nor is the events themselves, void of any noun predicates, anything other than empirically real events, which requires no space like separated detection of events. It is only by assuming that a lack of information entails the lack of a relativistic properties that evidence of FTL can be constructed. I'm therefore inclined to say:
1) Relational EPR is a local realistic interpretation, with the caveat that the relative 'events' are real irrespective of lacking noun predicates or observer independent variables.
2) Local realistic models can, at least in principle, be formulated consonant with Bell and Relational EPR, with the caveat being that the empirical content is contained in the form of relativistic (observer characterized) verbs.
3) Bell's theorem fails to rule out lhv models in which observables are relativistic observer dependent characterizations of an ensemble of verbs.

I spent hours yesterday with my philosopher of science colleague reading van Fraassen and Rovelli on RQM. We think we have it figured out (it's a challenge, thus the van Fraassen's paper). Crudely, it's information theory plus the light cone structure. Overall, physics is about information and special relativity and QM are rules for the exchange of information. RQM says information exchange is local per SR with correlations per QM. RQM does not provide an underlying mechanism for those QM correlations, so we were frustrated until we figured that out and quit looking for his ontology.

Given what I (mis?)understand about RQM, I would say it does not accomplish local realism, weakly or otherwise. He's in the nonseparable (not realism) class, clearly, but exactly how he doesn't say. I'm inclined to think he's saying QM is fundamental, so there is no "why" for its correlations. This is like SR postulating the constancy of c. It's a postulate, so there is no explanation for "why" everyone measures the same speed for light. It's just a brute fact about information and its exchange.

BTW, we think RBW can be used to provide a "why" for information theory and RQM, but that's another story.

 

[my_wan]

Eureka! I think I got it (somewhat)!
Since we know there can’t be a global universal NOW (RoS), there can’t be a global universal REALITY (for all observers), right!?

Yes, but there can be a form of general covariance. So in a relativistic sense it still describes the same thing, with different correlation statistics, measurements, etc. Not a separate reality as opined earlier in this thread. We already empirically know that EPR correlations are frame dependent.

http://arxiv.org/PS_cache/quant-ph/pdf/0604/0604064v3.pdf" for more detail on the interpretation as it relates to QM. Be aware that, as an interpretation, it remains model neutral. That doesn't preclude ontological extensions that go beyond purely the measured information without violating the legitimacy of RQM, as I pointed out in my last post to DrC. The sum total of all measurements is after all a complete specification of what we know or can empirically know, with or without theories that synthesis it in workable models.

And I must read it many times more to digest all. Rather 'shockingly' there seems to be parallels to what I was asking about in https://www.physicsforums.com/showpost.php?p=2716407&postcount=324", and the question of a wavefunction that collapses 'twice'.

Yes, I only mentioned the "twice collapsing wavefunction" once in passing. Actually my version was a collapsed wavefunction that wasn't collapsed for another observer. This can easily lead outside the EPR question of this thread, but I tend to think the formalized wavefunction consist of real quasi-localized fields we call particles, smeared (superimposed) over all possibilities not entirely relevant to a single self interacting particle (ensemble). This would indicate a the collapse didn't localize the particle, it merely reduced all possibles, from lack of a priori knowledge, to just the information relevant to that one particle. A large number of individual detections of self interacting particles must still be representative of all possibilities, as the formalized wavefunction requires.

Relational EPR is very cool in the sense that it tries to 'merge' GR & QM by a 'slight' modification of both interpretations of Einstein & Bohr, smart and very 'diplomatic'.

This "diplomacy" has strengths and weaknesses, and was predicated more on the notion of an "information theory" consonant with QM than diplomacy. It allows the interpretation to be model independent, and still allow logical cogency to be analyzed. Its weakness is that it doesn't by itself provide pointers to how to construct a model, consonant with RQM and/or GR, that could potentially lead us to new empirical content or unification. It's not that hard to access a models cogency with RQM after the fact though. Does P=NP?

I guess my 'rant' in https://www.physicsforums.com/showpost.php?p=2717199&postcount=331" is completely obsolete in the view of Relational EPR... sorry.

Yes, the single particle verses statistical ensembles of possibilities which may only be relevant in part to that single particle verses statistics of a large number of detections where all possibilities becomes relevant makes it somewhat difficult to think about. We know that particles are self interacting, so the wavefunction is relevant, at least in part, to single particles. Though I think it most likely that all possibilities is a useful fiction in the single particle case, while the particle is still a quasi-localized ensemble (field). You also seem to have gotten the issues that a Universal now would impose on present physics if it defines something that can't exist via RoS. If it's found to exist then it can't exist at any given time relative to a particular observer. It only goes stark raving mad from there, however easy it is to say now is now for me. I'll bow to anybody that can pull it off.

It looks like even DrChinese is out on thin ice...?

So am I. I've included a lot of opinion about what is possible here. However, I'm fairly confident in the main points of my claim as they relate to the EPR subject of this thread. Not as a fact of how nature is, but in the claim that EPR correlations fail to rule out the class of LHV theories specified.

I must digest and read again, but I shall return. Thanks for the link.

[PLAIN]http://upload.wikimedia.org/wikipedia/en/thumb/b/b0/Observer-observed.gif/350px-Observer-observed.gif
Observer O measures the state of the quantum system S

If you could, continue to try and poke holes in the possibility of LHV models of the class I've specified. It's difficult to learn from merely chasing support for a preexisting viewpoint. I'd like to hear your perspective of what you get from it anyway, and any questions or problems that I failed to address.

 

[unusualname]

Yes, I seek as few adjuncts to classical physics as possible. What I hope to have made clear, unless someone can provide a good counterargument, is that, at least in principle, it's possible to maintain both locality and realism. If someone can posit a rational FTL mechanism, that's empirically useful, I'll accept that as a local mechanism. The speed C is the limit of locality as we know because that's what it defines given our present understanding, not because it is, if faster effects exist. However, simply as a method of sweeping EPR under a rug is not a valid justification in my view.

Ok, perhaps so, but before that can be stated without equivocation, the objections I have articulated must be addressed. Merely stating it is so does not make it so. As for my reasons for avoiding non-local effects: Because the conceptual and mathematical nightmare it creates in trying to get it to coexist with what we know is beyond belief. Even QM presently is a tame beast in comparison. If it remains "consistent with other classical observations" then it must lack empirical meaning, outside of sweeping conceptual issues under the rug. The constraints of RoS are quiet severe.

Some of my own modeling attempts explicitly allow certain variables of sorts to randomly exceed C. Yet it's unworkable as an EPR mechanism, or any FTL summation. So I'm not adverse to FTL mechanisms as such, but merely to poke it in like some surgical instrument accidentally sewed into your body by a surgical doctor doesn't cut the mustard for me.

FTL is not a requirement for real wavefunctions. It does seem require a separation, at least in principle, between the waveform (itself an ensemble), and the ensemble imposed by on it solely by limitations of specific knowledge of that ensemble.


Ouch, I don't have a problem with the mind/body connection. I can even provide an empirically realistic self organizing 'toy' mind model, including memory, qualia, and evolutionary stages, with nothing more than metronomes and springs. Mathematically it's not really fundamentally new, but makes it easy to visualize how it leads to the empirical data. I generally find this kind of question involves the composition fallacy, and a failure to appreciate the nature and ubiquity of emergent properties. For this reason I find it interesting, but outside the scope here.

Perhaps even something that''ll fill the holes left by Bell's theorem.

I suspect that in labeling it "malarky" it's being interpreted within a singular myopic ontology. It was intentionally restricted in terms of an "information theory" for empirical and model independent consistency. Read my last response to DrC and I included at least one ontological model extension. If I took it as a final answer to the issues posed by QM, which I don't accept without GR, it would in fact be at the very least pointless. Understand what actually makes it work, and it gives you tools to think about real models, rather than just boring interpretations.

The most fundamental point I'm trying to make here is that, contrary to common opinion, EPR correlations don't entirely rules out all locally realistic theories. I've also provide the caveats that such models would require. I still have some interesting points to articulate for DevilsAvocado's last post. I look forward to defeat, if that is the truth, but the points actually need addressed for that to happen.

The problem you have is that not many people working in modern physics really care that EPR violations can be explained away by philosophical arguments about the nature of reality. You've mentioned the relational interpretation and an interpretation based on "probabilistic realism" (which I did reply to btw, I think you missed that since you claim your post was ignored) which are fun for those of a philosophical bent to ponder but for pragmatic scientists they are not very useful.

The relational interpretation is particularly unappealing, it just comes across as a clumsy way of extending einstein's spacetime relativity.

You (too) easily claim that consciousness may be explained by emergent properties in complex systems, as if that was a simple issue in comparison to explaining nonlocality!

The physical world is stuff A, consciousness is stuff B. Science will have to accept sooner or later that we haven't included stuff B in our models of reality.

Once we accept that stuff B has to be included we begin the next stage of our scientific development.

I don't think we need to throw deep philosophical arguments in just yet, science is about making theoretical models of how things work so as to make predictions or explain "why" something happens or is the way it is. Science starts with observations, and what I observe is that there is a physical world and there is my conscious awareness of this physical world. My conscious awareness is clearly not part of the physical world, so to model it scientifically I suggest it exists in is own separate "space", which mathematically we can model with extra dimensions appended to physical space or other topological constructs.

Our conscious thoughts seem to be able to have effects in the physical world and the physical world certainly affects our consciousness so we assume the two spaces are joined and can influence each other.

We can also assume consciousness is mundane and not something mystical, since it emerged from a mundane process, evolution.

Given that the only phenomena in science we know to be in conflict with classical local realism are quantum effects, it seems natural to assume consciousness and quantum effects are related, in particular it seems that entanglement and quantum computation gives a natural setting for our consciousness.

It also allows a natural solution to the problem of free-will: without conscious beings the universe is essentially the result of statistical physics. However, if we actually "are" a quantum system it seems reasonable to assume we can influence or "choose" quantum states in our own quantum system, so free-will is a conscious being selecting quantum states in his consciousness (which propagate to effects in the physical world). We do have to allow that an individual particle also has free-will, but if it's not related to any "desires" in a complex consciousness the "choices" made by individual particles are indistinguishable from random.

(Why we have desires to influence quantum states one way or another is complex, and the problem of the human condition)

Rather than argue subtle and complex philosophical issues this raises I like to imagine a simple "thought experiment":

Imagine a sophisticated computer based on Mars, which knows all current physics, observing the Earth's exterior for the last few billion years. The computer would record all physical events, eruptions, meteor impacts, climate change etc and fit them to its physics model without much trouble. But then in 1957 it sees a metal object shoot up from the surface and deliberately orbit the earth, in the years following it sees another metal object travel to the moon. How does it explain that with physics? Have conservation laws been broken? How can those events fit a physical model of the Earth which started as a relatively simple physical object, a big ball of molten rock.

Heck, we could even blow the Earth to pieces, maybe even the universe.

Without including consciousness (stuff B) as an additional component to reality in your scientific models you get nonsense.

So putting it all together, and returning to the OP's question, I suggest entanglement is due to signalling in the space of stuff B. It doesn't conflict with classical causality because the entire causal chain is restricted to the space of stuff B, although it may give rise to curious observations of backward events in the space of stuff A (classical space), it doesn't allow FTL signalling in the space of stuff A.

I don't even think this is a controversial model, it's bleedin' obvious.

 

[DevilsAvocado]

My conscious awareness is clearly not part of the physical world

Huh? Can that really be proven?

without conscious beings the universe is essentially the result of statistical physics.

Huh?? So the first 400 millions yrs after BB, before the first star was formed – and consciousness was impossible – the universe was a deterministic machine without HUP...??

But then in 1957 it sees a metal object shoot up from the surface and deliberately orbit the earth, in the years following it sees another metal object travel to the moon. How does it explain that with physics?

If the sophisticated Mars computer had a really good telescope, it could see the first tree deliberately rise from the mud. We don’t apply consciousness to a tree, do we...??

 

[DevilsAvocado]

If you could, continue to try and poke holes in the possibility of LHV models of the class I've specified.

You bet!
()

I think it’s time for some reconciliation... my brain is smeared out (superimposed) over all possibilities in trying to understand EPR – from DrC’s experimental-down-to-earth, to RUTA’s 'strange' RBW, and your 'special' RQM, and now comes an unusualname and propose that consciousness is the key...??

I got to think... (for a change ;)

 

[ThomasT]

In a local hidden variable model, each observer is measuring a separate reality. So there is no JOINT observable (or context).

That's right. (You're almost there.) But entanglement IS a JOINT observational context. (Let that sink in for a moment.)

Now, is what's being measured in the separate measurements at A and B the same as what's being measured jointly?
The answer is no. That's why I said:

It should become clear that the variables which determine individual detection rates can't be made to (can't be put into a form which would) account for the joint detection rates, because they aren't the determining factors in that situation.

... in a local world, what happens here does not affect what happens there.

That's right. But there are only two values for |a - b| where A and B are perfectly correlated (anticorrelated), and these perfect correlations are compatible with the assumption that the relationship between the entangled photons has a local common cause.

But, you might counter, the full range of entanglement stats can't be reproduced by a lhv description of the joint context. And that's correct, but it's because what's being measured in the separate measurements at A and B is not the same as what's being measured jointly.

A local hidden variable account of the joint context requires the parameter determining joint detection RATE (this parameter is the relationship BETWEEN the relevant individual property or properties of the disturbances incident on a and b) to be described in terms of the parameter determining individual detection SEQUENCE (this parameter is the relevant individual property or properties).

Hence our catch-22 situation: there's no way to model the joint situation using individual properties and get the full range of entanglement stats -- yet an lhv model requires the joint state to be described in terms of the individual properties, properties which, it's quite easy to see, can't possibly be put into a form which would account for the full range of entanglement stats. It's like requiring a peg to fit into a hole that, if you just look at the situation, it can't possibly fit into, and then making all sorts of wild speculations and new realities to account for why it doesn't fit into the hole.

If there is a "joint detection parameter" observable, it is global. That does not work in a local world either.

(1) The joint measurement parameter is |a - b|. (2) What |a - b| is measuring is the relationship between the counter-propagating disturbances. Both (1) and (2) are compatible with the assumption of c-limited locality.

So you may be correct ...

It is correct. But the presentation needs some refining.

... but you are not describing a local realistic model.

Hopefully it will become clear that I'm not trying to do that, but rather explain why such a model is impossible, and why the impossibility of constructing such a model doesn't imply nonlocality (or ftl info transfer) in Nature.

 

[ThomasT]

EPR fails and shows we need an additional (or
alternative) model to explain the observations of quantum
theory.

There is a local causal explanation for EPR. Just as
there is a local causal explanation for any entanglement stats. It's
just that these stats can't be predicted by an explicit lhv model. And
the reason for that has to do with a disparity between the requirements
of an explicit lhv model and the experimental situation that is being
modelled, independent of the consideration of locality, which is what
I've been talking about in my many posts in this thread.

Well, since what fails is local classical causality
...

No, that's not what fails. What fails is the requirement
that an experimental situation be modeled in terms of variables which
are irrelevant wrt the experimental situation.

... why not just accept that there's a mechanism
that allows non-local causality?

Because there's a simpler
explanation for why BIs are violated that doesn't require nonlocality
or any interpretation of qm other than the standard one.

-----------snip malarky -----------

There, that's much more reasonable than relational
interpretrations of reality and other such malarky. :)

No, it's malarky.

 

[ThomasT]

Since I haven't really received a proper rebuttal, perhaps some questions to clear up the distinctions I'm making between what is and isn't ruled out by EPR experiments, or attempts to paraphrase what I've said so I can see what the issue is.

The challenge is to explain why lhv descriptions of entanglement are impossible without resorting to artificial constructions of 'reality', or positing nonlocality or ftl transmissions, etc. I think that's possible.

Read what I've posted. Because if it's correct, then all of the speculative interpretations of qm which purport to account for violations of BIs are simply not necessary to account for violations of BIs -- and a rather well established interpretation of qm, namely dBB theory, might then need to be viewed as quite probably just wrong wrt its explicit nonlocality.

As long as we continue thinking that we don't or can't know exactly why BIs are violated, then the door is open to lots of stuff that would otherwise just be dismissed as being obviously silly.

But, what I'm saying is that we can know why BIs are violated and that it's right in front of us, and all we have to do is compare the requirements of an lhv theory with the reality (ie., the preparations) of entanglement experiments and it's immediately apparent why lhv descriptions of these experimental situations are impossible -- without resorting to nonlocality, or ftl, or dBB, or MWI, or RQM, or RBW, etc.

If one of your electrical appliances doesn't turn on, what's the FIRST thing you do? Check to see that it's plugged in, right? Unfortunately the equivalent isn't happening wrt speculations surrounding the incompatibility between lhv models and entanglement.

 

[unusualname]

Huh? Can that really be proven?

No, it's just an observation (that consciousness is not part of the physical world)

Huh?? So the first 400 millions yrs after BB, before the first star was formed – and consciousness was imp ossible – the universe was a deterministic machine without HUP...??

Well the uncertainty principle still applied, but (assuming no other conscious lifeforms had formed) the universe was deterministic in the sense of statistical physics, but remember that classical determinism doesn't imply perfect predictability due to the limitations imposed by chaos theory, even in a simple 3-body planetary system.

If the sophisticated Mars computer had a really good telescope, it could see the first tree deliberately rise from the mud. We don’t apply consciousness to a tree, do we...??

Ok a joke, but a tree doesn't do anything beyond what we can explain by simple physics, it doesn't have sophisticated inputs from the physical world (no non-trivial sense organs) either. Simple physics can't explain the journey taken by the Apollo rocket to the moon, since it was guided by conscious choices. I noticed some links were posted above to preprints discussing the behaviour of entangled systems in moving classical frames http://arxiv.org/abs/quant-ph/0302095 and http://arxiv.org/abs/quant-ph/0205179 , these results show that the classical observables in entangled systems vary according to the reference frame, but that's not unexpected since I would expect a form of special relativity to apply to any additional spaces appended to classical reality, just that we don't need to assume c is the limiting speed in that space. :)

 

[unusualname]

There is a local causal explanation for EPR. Just as
there is a local causal explanation for any entanglement stats. It's
just that these stats can't be predicted by an explicit lhv model. And
the reason for that has to do with a disparity between the requirements
of an explicit lhv model and the experimental situation that is being
modelled, independent of the consideration of locality, which is what
I've been talking about in my many posts in this thread.

By "explanation" I mean one that makes sense scientifically.

Because there's a simpler
explanation for why BIs are violated that doesn't require nonlocality
or any interpretation of qm other than the standard one.

-----------snip malarky -----------

Your "simple explanation" is the most convoluted one in the whole thread, at least mine is "simple" ;)

 

[IcedEcliptic]

By "explanation" I mean one that makes sense scientifically.



Your "simple explanation" is the most convoluted one in the whole thread, at least mine is "simple" ;)

I have been quietly reading this for some time, and I agree. I don't ascribe to the RUTA or unusualname view, but I recognize them as scientific and plausible.

Zonde, ThomasT, you are selling your own crazed theories.

 

[my_wan]

You bet!
()

I think it’s time for some reconciliation... my brain is smeared out (superimposed) over all possibilities in trying to understand EPR – from DrC’s experimental-down-to-earth, to RUTA’s 'strange' RBW, and your 'special' RQM, and now comes an unusualname and propose that consciousness is the key...??

I got to think... (for a change ;)

I've provided no better reason to presume my approach is any better than anybody elses. I would encourage not attaching to a particular view for purely anesthetic reasons. The point I hope to make clear is that EPR correlations, in spite of the very real constraints it imposes, does not support nor rule out local causality in general. That is the point relevant to the OP.

Personally, interpretations for their own sake is of very little interest to me. As a group they provide a space of possibilities, much like EPR correlations provides limits. I also consider observationally equivalent ontologies to the ontological interpretations provided. If an ontologically pleasing interpretation is all that is at stake, QM is just fine as is. But we still have the issue how to get QM and GR to play well together, with a formalism that provides empirical data, more than mere interpretations. The notion that interpretation alone is a useful construct is a stretch for me, especially with bigger game potentially available. Also, the notion that some things simply are because they are (fundamental) may in fact be so, but I think that presuming a priori that they are can be a self defeating self imposed limitation. The history of science supports the notion that fundamental principles can often be derived from more fundamental constructs.

So all the various interpretations have value, in their own way, but attempting to convince me that a given interpretation is the one true interpretation, like a one true absolute frame of reference, is a lost cause in my view. This multiplicity of views and approaches has value, often not as incongruent as supposed if you don't take ontologies as absolutes, and is an important part of the search.

 

[DevilsAvocado]

So all the various interpretations have value, in their own way ...

Okay, I hear you... so how do we proceed to find the TRUTH!?

()

 

[DevilsAvocado]

No, it's just an observation (that consciousness is not part of the physical world)

I’m curious about this. It’s our brains that have 'trouble' with EPR – not EPR itself (meaning the experiment ;).

I agree, it’s very "natural to assume consciousness and quantum effects are related", even though I personally don’t think it has anything to do with 'binary computing' – with the main objection that the brain is a living biological tissue with a electrochemical network, connected to a living body, which in turn are (must be) connected to other living bodies/brains in a social and cultural network, where the human language is the most important factor (put a newborn in an isolated box, and you will have a creature that has more common with a crazy chimpanzee than a human), whereas the quantum computer is stone dead, and completely alone, even if it has a NIC.

Could you imagine two quantum computers in love, 'connected' by a Cat5!?
Edit: And now I just realized netdating!

(My personal wild guess is that the brain is instead of binary 1/0, is utilizing 'analog chemistry' to build up 'thresholds' to trigger 'events', like falling in love, etc...)

Well the uncertainty principle still applied, but (assuming no other conscious lifeforms had formed) the universe was deterministic in the sense of statistical physics, but remember that classical determinism doesn't imply perfect predictability due to the limitations imposed by chaos theory, even in a simple 3-body planetary system.

Agree, and we can probably be 100% sure that no other conscious was available < 400 myrs, except if life could emerge from free-streaming radiation or cold dark matter...? This would be a miracle that would put EPR in 'kindergarten'!

... a tree doesn't do anything beyond what we can explain by simple physics ...

Huuum, can we really describe DNA and the "life of a tree" by "simple physics"...? Where is that formula??

I noticed some links were posted above to preprints discussing the behaviour of entangled systems in moving classical frames ...

The paper http://arxiv.org/abs/quant-ph/0205179" is very interesting (why did I miss that?). This seems to prove that the wavefunction is Lorentz invariant (covariant?), and my 'speculation' about RoS wavefunction contradictions is in-valid... still it’s hard to accept that the joint entanglement of the wavefunction can 'survive' this 'environment':

[URL]http://upload.wikimedia.org/wikipedia/commons/e/e4/Lorentz_transform_of_world_line.gif[/URL]
Views of spacetime along the world line
of a rapidly accelerating observer moving
in a 1-dimensional "universe"

 

[zonde]

I have been quietly reading this for some time, and I agree. I don't ascribe to the RUTA or unusualname view, but I recognize them as scientific and plausible.

Zonde, ThomasT, you are selling your own crazed theories.

Scientific means that there is something testable about idea apart from hand waving.
Where is that part in RUTA or unusualname views that you call them scientific?

My idea however can be tested easily any time (assuming of course you have equipment for basic Bell inequality test).
Another thing is that my idea is based on things that you observe in experiments and not on what's in other people heads. So you can call my idea crazy but it's much tighter bound with what you can observe out there compared to those plausible other ideas.

 

[my_wan]

I spent hours yesterday with my philosopher of science colleague reading van Fraassen and Rovelli on RQM. We think we have it figured out (it's a challenge, thus the van Fraassen's paper). Crudely, it's information theory plus the light cone structure. Overall, physics is about information and special relativity and QM are rules for the exchange of information. RQM says information exchange is local per SR with correlations per QM. RQM does not provide an underlying mechanism for those QM correlations, so we were frustrated until we figured that out and quit looking for his ontology.

The last sentence contains what it appears I need to respond to. No, it doesn't specify a mechanism any more than you specify a mechanism by which you know a heads up coin has tails down. Now your obviously not going to get 1 to 1 like a coin with ensembles and relational variables. Recall, as you noted, this cast not just RQM but QM itself as an "information theory". Thus the content of the wavefunction is a specification of what is known from prior measurements, not the actual physical content of it. Read the quote from the paper I provided DrC again:

http://arxiv.org/abs/quant-ph/0604064)]From[/PLAIN] the relational perspective the Heisenberg picture appears far more natural: \psi codes the information that can be extracted from past interactions and has no explicit dependence on time; it is adjusted only as a result of an interaction, namely as a result of a new quantum event relative to the observer. If physical reality is the set of these bipartite interactions, and nothing else, our description of dynamics by means of relative states should better mirror this fact: discrete changes of the relative state, when information is updated, and nothing else. What evolves with time are the operators, whose expectation values code the time-dependent probabilities that can be computed on the basis of past quantum events.

The lack of time dependence mentioned is because the information defined is only that information available from past interactions. The only thing that evolves with time is the empirical time-dependent probabilities computed from past quantum events. If this was a physical theory, rather than an information theory, then you could properly talk about the evolution of relative variables. This is important to realize, that the claim is that both RQM and QM are information theories. Talking about how two particles correlate spins in this situation is pointless, because all it really did was fill in information we couldn't obtain from past measurements. It's like wondering how the other side of the heads up coin knew to be tails, only we are dealing with ensembles of relational variables here (quantum events).

Given what I (mis?)understand about RQM, I would say it does not accomplish local realism, weakly or otherwise. He's in the nonseparable (not realism) class, clearly, but exactly how he doesn't say. I'm inclined to think he's saying QM is fundamental, so there is no "why" for its correlations. This is like SR postulating the constancy of c. It's a postulate, so there is no explanation for "why" everyone measures the same speed for light. It's just a brute fact about information and its exchange.

Nonseparable, in the sense used in RQM and claimed for QM, is the same sense in which 10 red and 10 blue marbles are randomly mixed and placed equally in each of 2 boxes. Now, without looking in those boxes, the "information" you have about the number of red and blue marbles in each box is nonseparable. Yet opening one box instantly provides information about what's in the other box, and requires no FTL mechanism regardless of separation.

Now RQM also justifies this "information theory" (RQM and QM) as a complete description of what can be known, and they're absolutely right in a 'purely' empirical sense. I still prefer a wider range of empirically equivalent model constructs.

BTW, we think RBW can be used to provide a "why" for information theory and RQM, but that's another story.

RBW is an impressive construct. How difficult would it be to recognize if its ontology was remodeled into an exactly equivalent logical construct that reversed the concept of motion again? The issues raised wrt RQM makes me question this. Ontologies are mostly more akin to coordinate systems that truth statements in my view, with some caveats.

 

[IcedEcliptic]

Scientific means that there is something testable about idea apart from hand waving.
Where is that part in RUTA or unusualname views that you call them scientific?

My idea however can be tested easily any time (assuming of course you have equipment for basic Bell inequality test).
Another thing is that my idea is based on things that you observe in experiments and not on what's in other people heads. So you can call my idea crazy but it's much tighter bound with what you can observe out there compared to those plausible other ideas.

OK, your idea is crazy.

 

[DevilsAvocado]

Nonseparable, in the sense used in RQM and claimed for QM, is the same sense in which 10 red and 10 blue marbles are randomly mixed and placed equally in each of 2 boxes. Now, without looking in those boxes, the "information" you have about the number of red and blue marbles in each box is nonseparable. Yet opening one box instantly provides information about what's in the other box, and requires no FTL mechanism regardless of separation.

Thanks my_wan for the marble analogy, it’s simple and beautiful.

I want to add a 'function' to this story, to make it 'compatible' with my understanding of what happen at Bell test experiments:

• 10 white and 10 white marbles are randomly mixed and placed equally in each of 2 boxes (i.e. entangled photons are spinless before measurement).
  
  
• Now, without looking in those boxes, the "information" you have about the number of marbles is that there are 10 white marbles in every box.
  
  
• We separate the boxes by 18 km, so they cannot influence each other.
  
  
• For the 'measurement' we have arranged a sloping bridge that randomly will make the marble roll of to the right, or to the left. If the marble goes left, it will land in red dyeing bath, and come out as a red marble for inspection. If the marble goes right, it will land in blue dyeing bath, and come out as a blue marble for inspection.
  
  
• When we run this experiment thousands of times, with different angles on the sloping bridge (thus changing the probability for red vs. blue) it turns out that the marbles in the two boxes are perfectly correlated with each other. And not only that, the actual correlation is corresponding exactly to the predictions of QM probabilities for marbles on a sloping bridge!

Now, did I poke a hole in the 'RQM Box', or not...!?

()

 

[my_wan]

Thanks my_wan for the marble analogy, it’s simple and beautiful.

I want to add a 'function' to this story, to make it 'compatible' with my understanding of what happen at Bell test experiments:

• 10 white and 10 white marbles are randomly mixed and placed equally in each of 2 boxes (i.e. entangled photons are spinless before measurement).
• Now, without looking in those boxes, the "information" you have about the number of marbles is that there are 10 white marbles in every box.
• We separate the boxes by 18 km, so they cannot influence each other.
• For the 'measurement' we have arranged a sloping bridge that randomly will make the marble roll of to the right, or to the left. If the marble goes left, it will land in red dyeing bath, and come out as a red marble for inspection. If the marble goes right, it will land in blue dyeing bath, and come out as a blue marble for inspection.
• When we run this experiment thousands of times, with different angles on the sloping bridge (thus changing the probability for red vs. blue) it turns out that the marbles in the two boxes are perfectly correlated with each other. And not only that, the actual correlation is corresponding exactly to the predictions of QM probabilities for marbles on a sloping bridge!

Now, did I poke a hole in the 'RQM Box', or not...!?

()

Cool, but I don't see this working, because as an information theory it is our information that lacks spin, not necessarily the photon. But, let's assume they are all white, and design out thought experiment (detectors) to better represent the conservation laws we do have information about. The same conservation law that require EPR correlations to begin with.

We have 20 white marbles. We collide (interact) pairs of marbles such that they leave this collision/interaction in opposite directions on the X axis. 18 km away, in each direction, we have a pair of side by side paint buckets such that one is on each side of the X axis in each direction. I'll also show this is still valid even if the marbles are never painted (relational interpretation).

Now, when one marbles lands in the (-X,Y) quadrant bucket, conservation laws demand that it is more probable that the other marble will land in the (X,-Y) bucket. Furthermore, we don't even have to paint the marbles when they land in our buckets, they remain white. We merely define marbles that land in the (-X,Y) and (X,Y) buckets as red, and (-X,-Y) and (X,-Y) as blue (opposite properties per correlation). Now red and blue becomes a purely relational concept, relative to the configuration of the bucket detectors and their overall geometry. In that case red and blue are no more real after the measurement than before, except relative to the measuring device.

Note: If QM is an information theory, as RQM posits, it can't be a priori claimed this is reasonable analogy of how it works, as it provides 'information' that's by definition not available. RQM does explicitly posit the relational properties analogous the the relational red and blue properties above. So, like Bell's theorem, even if we assume RQM is perfectly valid in principle, it does not prove no FTL mechanism exists or isn't involved, only that they aren't required.

 

[DrChinese]

If one of your electrical appliances doesn't turn on, what's the FIRST thing you do? Check to see that it's plugged in, right? Unfortunately the equivalent isn't happening wrt speculations surrounding the incompatibility between lhv models and entanglement.

You got the analogy backwards. This is exactly what happened in the 30 years from 1935 to 1965. A common view was that local realism was compatible with the predictions of QM. Bell put that to an end. At least mostly.

Anyway, I have personally spent plenty of time looking for cracks in Bell. Thousands of others have too. So you are really selling the physics community short, as well as repeating the same unsubstantiated claims.

 

[my_wan]

You got the analogy backwards. This is exactly what happened in the 30 years from 1935 to 1965. A common view was that local realism was compatible with the predictions of QM. Bell put that to an end. At least mostly.

Anyway, I have personally spent plenty of time looking for cracks in Bell. Thousands of others have too. So you are really selling the physics community short, as well as repeating the same unsubstantiated claims.

Here I agree with you, though I'm not so sure about "mostly".

EPR correlations do in fact rule out Einstein realism in the sense of absolute observables that can be completely passively observed empirically. Foundationally I don't see this as a problem, because something that exist but doesn't interact with anything isn't observable. Thus what we observe empirically are interactions, not things. However, with Bell's theorem we are provided with two choices: 1) Take the evidence EPR correlations provide as evidence to look beyond the standard local effects, which it is evidence though not proof. 2) Use the constraints imposed by EPR correlations to abandon that set of locally realistic models in contradiction, and try to ferret out the subset capable of maintaining consistency. Which to date hasn't provided any new physics, only interpretations with varying levels of cogency.

Both these possibilities needs investigated, and the first one to succeed, if either can, wins. Debate points notwithstanding, only physics. Thus there are no winners as of today. I therefore object to overstating claims on both ends.

ThomasT,
Yes, DrC is correct that your analogy unduly short changes a lot of awe inspiring work by many many brilliant people. Many things I once assumed were extremely unlikely in fact now has come to pass.

 

[DevilsAvocado]

Cool, but I don't see this working, because as an information theory it is our information that lacks spin, not necessarily the photon. But, let's assume they are all white, and design out thought experiment (detectors) to better represent the conservation laws we do have information about. The same conservation law that require EPR correlations to begin with.

Okay, you know these things better than me, and I’m 'digesting' RQM. But, still it seems to me that there is one thing missing in the story about the marbles, and I’ll highlight the 'weak' part in the red:

Nonseparable, in the sense used in RQM and claimed for QM, is the same sense in which 10 red and 10 blue marbles are randomly mixed and placed equally in each of 2 boxes.

To my understanding, the elegance of Bell in investigating "spooky action at a distance", was to implement "randomness at a distance", and setting the final parameters for the experiment in separate light-cones, thus prohibiting any local influence.

To me it looks like you implement the randomness at the "local source", and then put the objects in the in "closed information box". Is this really consistent with Bell test experiments (BTE)...?

Note: If QM is an information theory, as RQM posits, it can't be a priori claimed this is reasonable analogy of how it works, as it provides 'information' that's by definition not available. RQM does explicitly posit the relational properties analogous the the relational red and blue properties above. So, like Bell's theorem, even if we assume RQM is perfectly valid in principle, it does not prove no FTL mechanism exists or isn't involved, only that they aren't required.

I’m clearly missing something in RQM. I agree that QM is an information theory, and we really can’t know what’s in the "box". BUT, we can measure differences in different BTE setups. If we use not entangled photons in BTE, we get a result that don’t correspond to the predictions of QM, and if we use entangle photons – we get correspondence with QM predictions. This must mean that something happens that cannot be explained with 'every-day-local-reality', even if we all agree that there’s no 'usable information' sent FTL.

 

[ThomasT]

I have been quietly reading this for some time, and I agree. I don't ascribe to the RUTA or unusualname view, but I recognize them as scientific and plausible.

You have a strange interpretation of scientific and plausible.

Zonde, ThomasT, you are selling your own crazed theories.

Which indicates that you don't understand what either of us is saying. We're advocating certain approaches to different aspects of the EPR-Bell stuff.

Here's a link that explains what I'm saying better that I could:

http://arxiv.org/PS_cache/quant-ph/pdf/0001/0001112v3.pdf

 

[my_wan]

To my understanding, the elegance of Bell in investigating "spooky action at a distance", was to implement "randomness at a distance", and setting the final parameters for the experiment in separate light-cones, thus prohibiting any local influence.

You have to consider it in historical context (short version). This is a very very important historical piece to understand. If you get this everything should conceptually click into place.

When the mechanics was introduced by Born in 1926, the probabilities were to be understood as fundamental, without cause. A year later at the Solvay Conference, Heisenberg and Born declared the quantum revolution was over, that the physics was essentially complete and final. This stoked the famous Bohr–Einstein debates in earnest. Einstein used the conservation of energy to obtain information about the interference process, now called the EPR paradox, which he said contradicted the principle of indeterminacy. Einstein never suggested that the EPR correlations didn't exist. Ironically people now often think EPR correlations proves Einstein wrong, when in fact his argument depended on the correlations being real. If EPR correlations weren't real then his argument that they violate indeterminacy is invalid, i.e., ridiculous.

It became the accepted wisdom that indeterminacy was real, and the randomness was fundamental, without cause. Jump ahead 40 odd years, and we get Bell, Aspect, etc., with unambiguous experimental confirmation of EPR. Now, since indeterminacy is by definition true and fundamental, it means Einstein was wrong, even though he correctly predicted EPR correlations to argue against indeterminacy. Thus there must be some kind of new effect (FTL) to keep both indeterminacy and EPR correlations, and maintain that Einstein was wrong with his correct prediction. It is a paradox only because we still maintain that indeterminacy is true at the most fundamental level of nature.

Meanwhile, the search for a local EPR mechanism became the standard by which a search for hvt's was conducted, only with indeterminacy as a fundamental property in spite of EPR being correctly predicted by Einstein to undermine indeterminacy as a "fundamental" property.

Now here's the caveat: If their exist a causal mechanism for indeterminacy, such that it is real, but not fundamental, then EPR correlations prove exactly what Einstein said they prove. It is only through the acceptance of indeterminacy as a "fundamental" property that extra FTL mechanisms are needed to save the fundamental character of indeterminacy.

To me it looks like you implement the randomness at the "local source", and then put the objects in the in "closed information box". Is this really consistent with Bell test experiments (BTE)...?

Yes I did implement randomness at the "local source", and you rightly want to know if this really is consistent with EPR correlations. Well that depends. I'll lay out exactly what that depends on in the most general case.

1) If indeterminacy is a truly fundamental property of 'actual reality': then "local source" is not consistent.
2) If indeterminacy has a causal mechanism in 'actual reality': then "local source" is consistent.
(And we don't know what 'actual reality' is at this time, or even if it's a meaningful claim.)

Ironically (again to make this very important point clear), people often think that for Einstein to be right the correlation experiments must fail, when in fact Einstein correctly predicted them with the expectation that they were real, not to prove EPR correlations didn't exist, but to prove that because they did exist indeterminacy had a more fundamental cause.

Your next paragraph is perfect to finish this argument with.

I’m clearly missing something in RQM. I agree that QM is an information theory, and we really can’t know what’s in the "box". BUT, we can measure differences in different BTE setups. If we use not entangled photons in BTE, we get a result that don’t correspond to the predictions of QM, and if we use entangle photons – we get correspondence with QM predictions. This must mean that something happens that cannot be explained with 'every-day-local-reality', even if we all agree that there’s no 'usable information' sent FTL.

Note the "local source" legitimacy requirements above call for "actual reality". Note that RQM turns QM into an "information theory". If it's a theory about the information we have about the reality, rather than a theory about the reality of nature it claims to be, then by definition we can't claim any part of it as a fundamental property of "actual reality", including indeterminacy.

There are further constraints EPR correlations place on such hvt's. That is that indeterminacy is very real, just not a fundamental causeless property of nature. The only realistic way I know to pull that off is with ensembles of many properties, like the thermodynamic model I referenced. Ironically this means that constraints on the causal mechanism required to explain indeterminacy must itself be indeterminate, at least on empirical, not fundamental, grounds. More or less analogous to classical thermodynamic properties.

What I find strange here is people searching realistic causal mechanisms (FTL or not) when the very notion of a causal mechanism subverts the justification for needing a causal mechanism to explain EPR. Of course for FTL I guess it could be assumed EPR needs a causal mechanism, but indeterminacy doesn't. But what about the question of whether the wavefunction itself is real. That would directly imply a causal mechanism for indeterminacy, unambiguously subverting the need for a FTL causal mechanism for EPR correlations.

 

[ThomasT]

You got the analogy backwards. This is exactly what happened in the 30 years from 1935 to 1965. A common view was that local realism was compatible with the predictions of QM. Bell put that to an end. At least mostly.

My understanding was that qm and hidden variables were assumed to be incompatible due to von Neumann's influence. Bell pointed out the flaw in von Neumann's proof 30 years after Greta Hermann did (but noboday paid any attention to her). This is in one of the Mermin papers I referenced.

Anyway, I have personally spent plenty of time looking for cracks in Bell. Thousands of others have too. So you are really selling the physics community short, as well as repeating the same unsubstantiated claims.

What I'm talking about isn't a 'crack in Bell'. In my opinion, he really has ruled out lhv theories. You just don't get yet how that can be and still not need nonlocality or ftl propagations. The paper I linked to by Unnikrishnan in an earlier post should help clarify where I'm coming from.