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

[IcedEcliptic]

It is settled to the mainstream community. There are a few doubters. Of course, there are also doubters of a spherical Earth, General Relativity, the Big Bang, etc. If we found out everything we know is wrong, then this could be too.

Are you telling me that the Earth is not flat? Hogwash sir! ;)

 

[jtbell]

Are you telling me that the Earth is not flat?

And it's not supported by turtles all the way down?

 

[DevilsAvocado]

And it's not supported by turtles all the way down?

No worries mate! I’ve got it all covered!

 

[DevilsAvocado]

... Essentially 'entangled' means correlated.

This is an interesting point (that can be repeated). Erwin Schrödinger’s term Verschränkung is translated to entanglement, and this is (according to Anton Zeilinger) not as describing as the German term.

Verschränkung translated to English:
interleave
interconnection
folding
crossing
clasping​

Anton Zeilinger visualizes verschränkung like this:

(Entanglement in Swedish is something like 'spaghetti'... maybe that’s why I sometimes have a hard time digest... )

 

[IcedEcliptic]

And it's not supported by turtles all the way down?

I believe in the great turtle pile as the only sane anchor in a mad universe. ;) heh

 

[jtbell]

(Entanglement in Swedish is something like 'spaghetti'... maybe that’s why I sometimes have a hard time digest... )

I wonder what it is in Finnish. (Being of Finnish-American background, I have a more than passing interest in the language, but I haven't tried to study physics in it.)

 

[zonde]

Opinions put aside, do the Bell Tests and ones that Dr. Chinese is speaking of mean that this is a settled issue? I am not in this community, so I do not know.

What do you mean by "settled issue"? Settled using scientific method or settled by general consensus?
Anyways there is quite a big hole in reasoning about discarding local realism. Bell theorem rests on QM prediction that prefect correlations for any same (or orthogonal too in case of photons) angles do not depend form detection efficiency.
This is testable prediction however it has never been tested.

You can read what is in wikipedia about http://en.wikipedia.org/wiki/Scientific_method" :
"1. Use your experience: Consider the problem and try to make sense of it. Look for previous explanations. If this is a new problem to you, then move to step 2.
2. Form a conjecture: When nothing else is yet known, try to state an explanation, to someone else, or to your notebook.
3. Deduce a prediction from that explanation: If you assume 2 is true, what consequences follow?
4. Test: Look for the opposite of each consequence in order to disprove 2. It is a logical error to seek 3 directly as proof of 2. This error is called affirming the consequent."

 

[DevilsAvocado]

I wonder what it is in Finnish.

...I’m not sure, but could it be Nokia...??

Noo sorry, entanglement = Lomittuminen, and the word for QM is really cool Kvanttimekaniikka. Just taste that word (imagine sitting in a real hot sauna), it’s definitely hotter than QM!

(P.S. There’s a "friendly war" between Finnish Nokia and Japanese/Swedish Sony Ericsson, but in the end we are all brothers and sisters, even in ice hockey! )

 

[my_wan]

[...](Entanglement in Swedish is something like 'spaghetti'... maybe that’s why I sometimes have a hard time digest... )

Reasonable synonyms in English, but I believe that's what Francis Bacon would refer to as an "idola fori" (idol of the marketplace). To say that a variable is entangled does not endow that variable with the realism of spaghetti. Now if these variables unambiguously possessed these presumed ontic qualities, then where's the FTL communicator? Without that your still stuck with interpretive ambiguity, though something clever in the vein of Bell's Theorem might pull it off.

The Monty Python humor is cool, but until EPR can directly address this relational class, rather than violating the relational objections to formulate arguments against it, it remains just humor. The only honest answer to the OP then remains: It's potentially possible, simply because nobody has any hard answers. I'm still waiting on a cleaner empirical rebuttal to the relational model class.

 

[zonde]

Thought that I might add something to my last post.
In wikipidedia "affirming the consequent" is described as negative thing without looking at positive sides of this approach. Really there are other occupations of people that take advantage of that approach - it's engineering.

So if we do not call modern QM a science but engineering then everything falls in places and all things are fine the way they are.

 

[DevilsAvocado]

... do not call modern QM a science but engineering ...

Healthy reflection zonde. This approach has the big advantage of eliminating any 'religious elements'. If you put your head in the sand at a construction site, then you risk being buried in cement. ()

I’ agree 99.9%, with reservation for the fact the whole universe is inside this "construction site", and this must have some influence on the matter...

 

[DevilsAvocado]

... Now if these variables unambiguously possessed these presumed ontic qualities, then where's the FTL communicator? Without that your still stuck with interpretive ambiguity, though something clever in the vein of Bell's Theorem might pull it off.

I agree.

I have tried many times, and this is last try (before maybe starting a new thread). I see two paradoxes in EPR/Bell test experiments:

1) The official "Spukhafte Fernwirkung".

2) The 'madness' of SYNCHRONIZED ENTANGLED OUTCOMES.

If we compare with the double-slit experiment, we don’t have this problem. The wavefunction (of the wave–particle duality) is propagating perpendicular towards the double-slit and passes simultaneously. No problem, no paradox.

Whereas in Bell test experiments we have a wavefunction of two particles (or more!), that are separated outside each other’s light-cones, and have this far been tested at 18 km separation.

Now, to have one influence the other we need "Spukhafte Fernwirkung". But this is not enough, some function/property/mechanism must also resolve which one of the particles is going to DECIDE the correlated outcome.

It won’t work if they are exactly synchronized, because this will create a conflict with QM, HUP and probability.

It will only work if they are unsynchronized, but then we run into problem with GR who says that in some frame of reference they will be exactly synchronized, and in another frame of reference Alice will set the outcome, and in another frame of reference Bob will set the outcome!?

>> This doesn’t work with current understandings of QM and GR!? << ​

(... as far as I can tell ...)

 

[IcedEcliptic]

Scandinavian languages make my brain hurt. Lovely to hear, but painful to read and pronounce.

 

[DevilsAvocado]

Scandinavian languages make my brain hurt.

Yeah, I hear you.

This guy has completely destroyed our reputation!

https://www.youtube.com/watch?v=<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/mbs64GvGgPU&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/mbs64GvGgPU&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>

 

[unusualname]

Here is a paper that shows a violation of Bell's inequalities in classical statistics, among other things.

Abstract: http://arxiv.org/abs/0906.4919" Section VIII covers Bell's inequalities. I can't honestly disparage considerations that local realism may in fact be a dead horse. What I can disparage is the claim that it is certainly so. It's not entirely honest on either side of the fence.

But he doesn't claim this supports local (deterministic) realism, instead he proposes that reality is based on "probabilistic realism":

“Probabilistic realism” starts from the premise that the most general fundamental description of reality is of statistical nature [13]. “Elements of reality”, which allow for definite predictions, correspond then to values of observables as well as to correlations. Let us consider the EPR case of two entangled spins, carried by spatially separated particles which originate from the decay of a spinless particle and therefore have total spin zero. In this case the element of reality is the maximal anticorrelation for all spin directions, rather than values of individual spins. This element of reality is revealed by measurements of both spins and has existed already before the first measurement. In contrast, the value of one of the spins is maximally undetermined before the first measurement and not an element of reality.
Due to the correlation, the two spins have to be considered as one system. Even for an arbitrarily large separation, such that signals cannot be exchanged any longer, we cannot divide the system into two independent subsystems, consisting of one of the spins each. The correlation between the two spins is then nonlocal.

which is hardly what most of you local realists mean by local realism :)

I think I prefer nonlocal deterministic realism to this suggestion anyway, and I'm sure the most profitable way forward is to determine possible non-local models of reality, in that regard papers like this one An experimental test of non-local realism are interesting (rules out a class of non-local models)

 

[ThomasT]

It's clear that Bell Test (violation) experiments are correct (to anyone sensible), and it's also clear that Special Relativity is correct, so to account for entanglement we need either "magic" or a FTL causal mechanism that doesn't contradict SR.

There's almost universal agreement that the tests are correct. But neither magic nor ftl transmissions (nor aliens, etc.) are necessary to understand why the correlations exceed the limits on explicit lhv accounts of them.

To understand why BIs are violated it's necessary to compare the formal requirements, as set forth by Bell, with the experimental setups to which they're being applied (formal requirements that any explicit local hidden variable model of the joint, entangled, situation must meet). 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. Rather it's relationships between these variables that's being measured in the joint context. These relationships are joint hidden parameters that are being measured by a joint instrumental variable. This is what the 'quantum nonseparability' of the situation physically refers to. QM gives a correct account of the joint, entanglement, situation by not separating its components.

The above point is the key to understanding what Bell's theorem means and why it's impossible to have a local hidden variable model of entanglement. It's not that Bell was wrong or that he unwittingly made a faulty lhv model. Making a lhv model of entanglement is kind of a catch-22. The only way to represent the joint situation with local hidden variables happens to be incompatible with the demands of the situation that it's trying to model. An lhv account of the joint, entangled, situation must necessarily be an incorrect account of that situation. This has been proven by Bell and others (see David Mermin's, "Hidden variables and the two theorems of John Bell", Rev. Mod. Phys., Vol. 65, No. 3, July 1993). So, BIs (and other 'no lhv' theorems) based on the requirements necessary to construct any explicit lhv model of the joint, entangled state, experimental situation must, necessarily, be violated -- and this has nothing to do with nonlocal or ftl communication between the separated entangled quanta or the separated filtering and detection devices. The joint experimental situation is just, in Bell's words, "incompatible with separable predetermination". This doesn't mean that there aren't separate particles that have predetermined unknown individual properties. It just means that the joint experimental situation can't be modeled in those terms. (What sometimes sets people on the wrong path is Bell's statement in the conclusion of his 1964 paper, "On the Einstein Podolsky Rosen Paradox": "In a theory in which parameters are added to quantum mechanics to determine the results of individual measurements, without changing the statistical predictions, there must be a mechanism whereby the settings of one measuring device can influence the reading of another instrument, however remote." Which is correct of course. However, since there's no particular reason to believe that our universe might work that way independent of 'no lhv' theorems, and since BI violations can be explained without such a mechanism, then there's no particular reason to invent such a mechanism.)

Once that's understood, then it remains to understand how the correlations can be produced in a universe in which the principles of SR and local action hold. It should be clear enough that if there's some predetermined underlying relationship between, say, the spins of two photons, and that if these photons are jointly analyzed by crossed polarizers, then the correlations which result are pretty much what would be expected in a locally causal c-limited universe. Local predetermination of individual properties is incompatible with qm, because, for the reasons mentioned above, accounts of joint, entangled state, experimental situations in those terms are, necessarily, incompatible with those experimental situations.

This is not to say that the underlying mechanisms which result in entanglement correlations are completely, or even well, understood. They aren't by any means. And understanding that a local common cause for the underlying entanglement isn't ruled out by 'no lhv' theorems is just a beginning to any approach that's in line with relativistic restrictions. So, it's suggested that, before weird and absurdly strange scenarios are offered to account for the BI violations and entanglement stats, maybe the focus should stay on the subtleties of the still fascinating, even without any artificially added wierdness, facts of the science and analysis and interpretation that promise to facilitate a better understanding.

So, for the record, I agree with those (eg., David Mermin, see his "What Do These Correlations Know about Reality? Nonlocality and the Absurd) who think that positing the existence of, eg., nonlocality is not in keeping with the best practice of scientific inquiry.

 

[my_wan]

Now, to have one influence the other we need "Spukhafte Fernwirkung". But this is not enough, some function/property/mechanism must also resolve which one of the particles is going to DECIDE the correlated outcome.

This is at the core of the problem. Yet the justification that one must have actually influenced the other, at the time of measurement, is predicated on the unreality during transit and reality at the time of measurement. If these correlations were actually present during transit, then no such 'communication' is needed. The only way to deny this possibility is to deny the reality posited by such models during transit, then requiring what has been denied at the time the measurement takes place. No mechanism is required to "DECIDE" the correlation if it already exist.

You then made a more specific claim, that without a valid response moots my argument above.

It won’t work if they are exactly synchronized, because this will create a conflict with QM, HUP and probability.

Here you specified "exactly synchronized". But "exactly" has implications that may not be valid. I'll use a well known paper by Hall and Reginatto to illustrate.
http://arxiv.org/abs/quant-ph/0102069"

http://arxiv.org/abs/quant-ph/0102069]An[/PLAIN] exact uncertainty principle, formulated as the assumption that a classical ensemble is subject to random momentum fluctuations of a strength which is determined by and scales inversely with uncertainty in position, leads from the classical equations of motion to the Schrodinger equation. Thus there is an exact formulation of the uncertainty principle which precisely captures the essence of what is "quantum" about quantum mechanics.

Thus, by analyzing HUP as something somewhat analogous to Brownian motion, a version of HUP was derived from which the Schrodinger equation could then be directly derived. You should also note that this assumed a "classical ensemble", not an absolute valued variable in and of itself. Thus the implication by "exactly synchronized" does not entail that the measured variable is itself an absolute valued variable. Yet we all know that a large ensemble of random variables can be characterized by non-random values, and non-local effects are not needed to arrive at this value. Nor are we required to assume these variables don't exist without measurement, even though they lack real meaning wrt individual elements of a defining ensemble, classical or otherwise. "Exactly", "HUP", "QM", and "probability" has not only been maintained, but defined by and extended to include the Schrodinger equation in exact uncertainty case.

This addresses the "exactly synchronized" issue, but a more general issue implied in your rebuttal needs mentioned. Though I doubt you intended to imply this. In general when speaking of what is in "conflict" with a theory we are limited to empirical "conflict", irrespective of how incongruent the principles used to arrive at the empirical content appears to be. It's my opinion that ontologies have a symmetry similar to coordinate dependence, which we know is untenable in the general case. There can also be a form of covariance between incongruent but empirically equivalent ontologies. Many debates result from these sometimes equivalent but incongruent ontologies, and we call it arguing semantics.

 

[DrChinese]

...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. Rather it's relationships between these variables that's being measured in the joint context. These relationships are joint hidden parameters that are being measured by a joint instrumental variable...

Again, no. In a local hidden variable model, each observer is measuring a separate reality. So there is no JOINT observable (or context). This is by definition, but also comes from the EPR definition of an element of reality: if the outcome can be predicted with certainty, then there is an element of reality. And in a local world, what happens here does not affect what happens there.

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.

 

[my_wan]

But he doesn't claim this supports local (deterministic) realism, instead he proposes that reality is based on "probabilistic realism":

“Probabilistic realism” starts from the premise that the most general fundamental description of reality is of statistical nature [13]. “Elements of reality”, which allow for definite predictions, correspond then to values of observables as well as to correlations. Let us consider the EPR case of two entangled spins, carried by spatially separated particles which originate from the decay of a spinless particle and therefore have total spin zero. In this case the element of reality is the maximal anticorrelation for all spin directions, rather than values of individual spins. This element of reality is revealed by measurements of both spins and has existed already before the first measurement. In contrast, the value of one of the spins is maximally undetermined before the first measurement and not an element of reality.
Due to the correlation, the two spins have to be considered as one system. Even for an arbitrarily large separation, such that signals cannot be exchanged any longer, we cannot divide the system into two independent subsystems, consisting of one of the spins each. The correlation between the two spins is then nonlocal.

(Bolding and underlining added to make my point.)

Here it says: "This element of reality is revealed by measurements of both spins and has existed already before the first measurement." Thus no signaling mechanism is required to establish a correlation when the measurement takes place. It goes on to say: "In contrast, the value of one of the spins is maximally undetermined before the first measurement and not an element of reality." But what does "maximally undetermined" mean here wrt one spin, that doesn't exist with both spins? It is our knowledge that is "maximally undetermined", not the spin state itself. Consider the following analogy.

You have a red and a blue marble. You have a machine package them in separate boxes without any knowledge of what color is in each box, and ship one around the world. Now, in the case of both marbles, like both spins, the color of both marbles is fully determined before the first measurement, as specified in the quote. Also, the color of the marble in anyone box is "maximally undetermined", because you don't know which marble is in which box, as specified in the quote. Yet the colors are correlated, because knowledge of one provides full knowledge of the other. You can only assume a FTL mechanism if you deny that the marbles had a color before opening one of the boxes.

Now we also know that these QM correlations cannot correspond to singular properties of a singular object, like in the marble sense. Bell's ingenuity made that crystal clear. If the logic holds in the QM sense, then the properties must be defined by ensembles, group behavior/relations which defines the properties. We know, classical or not, that a large number of random variables can be summed as a single well defined variable. Only when we put these variable into two groups, we can't define what each group separately will sum to, without first measuring at least one group. We also know that disparate emergent properties of ensembles can be formalized as if a single entity, if we drop (or don't know) the identifiers which define them.

which is hardly what most of you local realists mean by local realism :)

I run into realists 'priest' all the time, and these are a bigger pain than they are worth. However, given the misrepresentation apparently provided in your rebuttal, I think it would be a bit difficult to define what one particular realist means. I'm not even sure "most" is definable.

I think I prefer nonlocal deterministic realism to this suggestion anyway, and I'm sure the most profitable way forward is to determine possible non-local models of reality, in that regard papers like this one An experimental test of non-local realism are interesting (rules out a class of non-local models)

I take the opposite tack, but given what we know at this point it would be unreasonable for me to insist my approach will be the most profitable. I'm not so certain as you have stated yourself to be here. I am a bit more certain that certainty in your own view can be a liability to a fruitful search, even if your lucky enough to be essentially right. My own modeling efforts actually include FTL variables of sorts, they just happen to be unusable for EPR and similar effects.

 

[my_wan]

Again, no. In a local hidden variable model, each observer is measuring a separate reality.

Funny, I've never seen it that way. There's MWI which is a class of its own, but certainly not universal to lhv models. There's another way I could interpret this, but it would be essentially equivalent to stating that two observers that measure the velocity of the same object differently must be measuring a "separate reality". Of course general covariance is a difficult issue in QM.

So there is no JOINT observable (or context). This is by definition, but also comes from the EPR definition of an element of reality: if the outcome can be predicted with certainty, then there is an element of reality. And in a local world, what happens here does not affect what happens there.

Yet I still haven't even seen an acknowledgment of definitions not contained in the EPR definition, nor what those definitions entail. If you restrict the discussion solely to realism as defined by EPR, then logical validity goes without saying. Yet there are entire well defined classes of models which EPR definitions don't apply. You can legitimately ignore them as a personal preference, but stating what certainly is or isn't so, on the basis of a priori rejections of logical classes, doesn't follow.

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 give a marble analogy of a joint detection parameter to unusualname. Then pointed out how EPR puts constraints on this logic through ensembles rather than singular objects with singular properties. I'd still like to hear a rebuttal that does a prior reject the reasoning in order to reject the reasoning.

 

[unusualname]

So, for the record, I agree with those (eg., David Mermin, see his "What Do These Correlations Know about Reality? Nonlocality and the Absurd) who think that positing the existence of, eg., nonlocality is not in keeping with the best practice of scientific inquiry.

yes, but it's much more fun to speculate on non-locality :)

When De Broglie suggested wave-particle duality in 1923, it was a pretty crazy looking suggestion at the time which bypassed a lot of tortuous alternative philosophical and analytical proposals, but turned out to be a spectacularly successful scientific model.

It's quite possible that Entanglement "paradoxes" will turn out to be due to us being restricted to observing a projection of reality, so we don't really see the real picture, like in the holographic principle which, amongst other things, proposes that all information in a volume is obtainable from the surface area surrounding it.

So the non-locality may be illusory due to us being restricted to observing a subset of reality (although it appears to be non-local behaviour in that subset)

 

[IcedEcliptic]

Ah yes, the science of personal preference.

 

[my_wan]

Ah yes, the science of personal preference.

It plays a legitimate role in science when dealing with open questions, unless you think a psychic would do better directing research. It makes no sense for everybody to explore exactly the same set of assumptions, and such preferences distribute these searches more realistically. The danger is when we wrongly insist opposing assumptions are invalid, and artificially restrict research to our personal preferences. Certainly there are closed questions, but we must be careful not to over generalize and close questions that the physics involved didn't specifically close.

 

[DevilsAvocado]

This is at the core of the problem.

I’m sincerely thankful for this comment. I was about to give up, convincing myself I was "lost in translation". Thank you so very much for this.

No mechanism is required to "DECIDE" the correlation if it already exist.

This makes me a little 'nervous' again... do you mean that LHV is still a reasonable possibility??

Here you specified "exactly synchronized". But "exactly" has implications that may not be valid.

Bad formulation of me, I’m sorry. What I wanted to pin down is the problem of Relativity of Simultaneity (RoS), and the fact that entanglement seems to be in need of a global NOW, to work properly.

One weird way to get rid of this problem is to accept Relational Blockworld (RBW) – No movement of particles in spacetime whatsoever.

Another is Many Worlds Interpretation (MWI) – EPR is no paradox and works just fine, in branched and separated universes.

And we can rule out a universal global NOW – since, for example, the GPS satellites needs adjustments for relativistic time dilation effects, essential for the functioning of the system.

So if we skip "interpretations under development" and look at what we 'have today', I say we have some 'trouble' in getting entanglement working.

My hope is that the QM world isn’t that 'crazy' that it’s impossible to 'talk about', and make some sense, in plain language. I could of course be totally wrong; QM world is 'crazy' and/or impossible to talk about. But I sure hope not. (Note: I’m not talking about superposition etc, simultaneously spin up/down – that’s not crazy, just weird.)


In an attempt to get over 'ontology & semantics', I’ll take a real dramatic example:

1) Alice & Bob are going to play "Russian Entangled Roulette".

2) Two revolvers with all rounds are connected to the measuring apparatus, and adapted to Alice & Bob’s heads.

3) If spin up (+) is measured, the revolver will not fire. If spin down (-) is measured, the revolver will fire.

4) Alice & Bob are separate by 1 ly, with the source halfway.​

PROBLEM:
In one observer's reference frame we could see Alice’s photon hitting the polarizer first, and measure (+), thus killing Bob by deciding he is going to measure (-).

In another observer's reference frame we could see Bob’s photon hitting the polarizer first, and measure (-), thus saving Alice by deciding she is going to measure (+).

Would you be Alice lawyer in court?

Or what I’m really getting at – how do Alice & Bob’s photons know which reference frame they are in? Either the wavefunction/entanglement is broken/measured – or it is not. You can’t be in a state 'in-between' or 'both', can you? The wavefunction can’t collapse 'twice', can it?

 

[IcedEcliptic]

It plays a legitimate role in science when dealing with open questions, unless you think a psychic would do better directing research. It makes no sense for everybody to explore exactly the same set of assumptions, and such preferences distribute these searches more realistically. The danger is when we wrongly insist opposing assumptions are invalid, and artificially restrict research to our personal preferences. Certainly there are closed questions, but we must be careful not to over generalize and close questions that the physics involved didn't specifically close.

Pretty way of saying that what you and zonde and thomast are on about is not really physics.

 

[my_wan]

This makes me a little 'nervous' again... do you mean that LHV is still a reasonable possibility??

In principle yes, but EPR correlations do place very definite restrictions on any such models. I thought I covered those conditions in my responses and papers I referenced for details. I give a marble analogy but Bell's theorem does in fact rule out such singular objects with singular properties. 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.

Bad formulation of me, I’m sorry. What I wanted to pin down is the problem of Relativity of Simultaneity (RoS), and the fact that entanglement seems to be in need of a global NOW, to work properly.

Yes indeed, IIF a signaling mechanism is required. However, if you accelerate, there's no reason to be surprised that all distant objects change apparent velocity instantly, exactly according to your definition of simultaneity. Yet no signaling is involved. If 1) and 2) above apply, then this is all that's involved with EPR correlations. In fact, the difficulties RoS imposes seems to lend more support to this view.

One weird way to get rid of this problem is to accept Relational Blockworld (RBW) – No movement of particles in spacetime whatsoever.

Yes, I've only been aware of RBW a few days, and it's very interesting. However, fundamentally RBW appears to take advantage of the relational view I've been discussing, in an upside down sort of way. The Blockworld does require the entire context to be accounted for.

Another is Many Worlds Interpretation (MWI) – EPR is no paradox and works just fine, in branched and separated universes.

Yes, except it lacks empirical justification, beyond the need for sweeping a range of issues under the rug. Maybe that can change, but so far all I see is a lot of stacking of dependent variables.

And we can rule out a universal global NOW – since, for example, the GPS satellites needs adjustments for relativistic time dilation effects, essential for the functioning of the system.

So if we skip "interpretations under development" and look at what we 'have today', I say we have some 'trouble' in getting entanglement working.

Yes, very endemic trouble. This is why I look at the issues from a class level, rather than specific models. Hopefully this will be useful in providing some viable clues where to go from here.

My hope is that the QM world isn’t that 'crazy' that it’s impossible to 'talk about', and make some sense, in plain language. I could of course be totally wrong; QM world is 'crazy' and/or impossible to talk about. But I sure hope not. (Note: I’m not talking about superposition etc, simultaneously spin up/down – that’s not crazy, just weird.)

Yep, I'm in this boat, but realistically we can't demand it a priori. So I begin with the strongest causality, and give up what the physics says I must, like the marble analogy under EPR is fully untenable. The there are a whole range of notions, common here, which give up even more but are quiet reasonable assumptions, with a fair likelihood of paying off.

In an attempt to get over 'ontology & semantics', I’ll take a real dramatic example:

1) Alice & Bob are going to play "Russian Entangled Roulette".

2) Two revolvers with all rounds are connected to the measuring apparatus, and adapted to Alice & Bob’s heads.

3) If spin up (+) is measured, the revolver will not fire. If spin down (-) is measured, the revolver will fire.

4) Alice & Bob are separate by 1 ly, with the source halfway.​

PROBLEM:
In one observer's reference frame we could see Alice’s photon hitting the polarizer first, and measure (+), thus killing Bob by deciding he is going to measure (-).

In another observer's reference frame we could see Bob’s photon hitting the polarizer first, and measure (-), thus saving Alice by deciding she is going to measure (+).

Would you be Alice lawyer in court?

Or what I’m really getting at – how do Alice & Bob’s photons know which reference frame they are in? Either the wavefunction/entanglement is broken/measured – or it is not. You can’t be in a state 'in-between' or 'both', can you? The wavefunction can’t collapse 'twice', can it?

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. Fundamentally, in this case, it would be no different from all bullets in one gun without knowing which, and both triggers are pulled. The superposition of both guns tells us exactly how many bullets there is. Without looking we could know nothing about the bullets in anyone gun. This is untenable given Bell's theorem, unless the guns are ensembles that can overlap, and you positioned properly relative to the gun. Only the formalism does not make a distinction between an actual overlap of ensembles and an apparent overlap due to our lack of location knowledge. We merely superimpose all possible locations as if all possibilities was the reality, justified on the fact that the waveforms can and do overlap, and required for valid statistical answers.

Years ago, in Jr High, I read "In Search of Schrodinger's Cat". By the time it finally got around to saying what was supposed to be so weird, I thought I had guessed the answer. I figured it was a cross frame effect in relativity. Several years later, when I finally learned how untenable this was, it unambiguously brought home the meaning of general covariance. I even embarrassed myself on this forum once, falsely thinking somebody else made this mistake. You can reverse the apparent order of events visually, but once you account for the intervals involved no change in event ordering occurs. 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.

 

[my_wan]

Pretty way of saying that what you and zonde and thomast are on about is not really physics.

Haven't payed much attention to what zonde and ThomasT have said, though I believe it was ThomasT that was backed into an untenable corner iirc. I'm more interested in views that can potentially demonstrate that I'm wrong. Pretending that a class of models that are ruled out by physics (EPR) when they are not is 'effectively' a pretense about being physics. Thus the debate belongs on the issue of how I'm wrong, and how the relational interpretation is ruled out by EPR correlations. Not on labels you can impose on me to impune.

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

This paper actually weakens the notion of realism, at least as it relates to the variables under question, yet contains the points I have been making. It's not me making demands on how things are, only pointing out that a certain class being rejected is not ruled out by EPR correlations.

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.

 

[DrChinese]

Haven't payed much attention to what zonde and ThomasT have said, though I believe it was ThomasT that was backed into an untenable corner iirc. I'm more interested in views that can potentially demonstrate that I'm wrong. Pretending that a class of models that are ruled out by physics (EPR) when they are not is 'effectively' a pretense about being physics. Thus the debate belongs on the issue of how I'm wrong, and how the relational interpretation is ruled out by EPR correlations. Not on labels you can impose on me to impune.

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

This paper actually weakens the notion of realism, at least as it relates to the variables under question, yet contains the points I have been making. It's not me making demands on how things are, only pointing out that a certain class being rejected is not ruled out by EPR correlations.

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.

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

 

[unusualname]

Haven't payed much attention to what zonde and ThomasT have said, though I believe it was ThomasT that was backed into an untenable corner iirc. I'm more interested in views that can potentially demonstrate that I'm wrong. Pretending that a class of models that are ruled out by physics (EPR) when they are not is 'effectively' a pretense about being physics. Thus the debate belongs on the issue of how I'm wrong, and how the relational interpretation is ruled out by EPR correlations. Not on labels you can impose on me to impune.

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

This paper actually weakens the notion of realism, at least as it relates to the variables under question, yet contains the points I have been making. It's not me making demands on how things are, only pointing out that a certain class being rejected is not ruled out by EPR correlations.

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.

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.

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?

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.

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.

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)

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

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

 

[RUTA]

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

I can't speak for the (few) others who prefer violations of realism to locality, but I don't want to give up relativity of simultaneity (no preferred frame) and I don't want to talk about the "future causing the past" (if the future is already "there," then you've a blockworld and nothing "happens" in a blockworld anyway) -- either or both of these obtain with causal non-locality. No matter the mechanism, if you have A causing B when A and B are space-like related, you have causal non-locality, so I opted for nonseparability. I think it's healthy for the overall effort at unification to have advocates for all the possible interpretations of QM.