I Entanglement: is there 'action at a distance' due to measurement?

[timmdeeg]

Two particles, A and B, are entangled. The measurement of A yields spin-up.

What happens to B in that instant of time?

a) is B still a quantum object and as such doesn't possess definite spin properties before measurement?

b) has B the definite property spin-down even prior to its spin measurement?

What means action on a distance in this context, if at all?

 

[PeroK]

Two particles, A and B, are entangled.

It's conceptually clearer to describe this as a system of two particles in an entangled state. See below.

The measurement of A yields spin-up.

Again, it's conceptually clearer to say that the system of two particles is measured and particle A is measured as spin-up about a given axis.

What happens to B in that instant of time?

The system of two particles is now in an unentangled state. The state of the non-local system has changed, as result of the measurement. The particles are now independent, although each is in an eigenstate of spin about a given axis.

a) is B still a quantum object and as such doesn't possess definite spin properties before measurement?

There's no problem with a particle being in an eigenstate of spin about a given axis. The measurement of the entangled system has effectively done that to both particles. The spin about other axes is indeterminate - as it would be with any measurement of spin about a given axis.

b) has B the definite property spin-down even prior to its spin measurement?

Again, this is no different from any measurement of a particle. After the measurement, the particle is in an eigenstate of spin about that axis. Repeated measurements of spin about the same axis must result in the same outcome.

It seems to have been a common theme recently that people asking about QM don't realise that systems in an eigenstate of a given observable will have a definite measurement outcome for that observable. This is not something where entanglement contradicts the rest of QM.

What means action on a distance in this context, if at all?

It has no meaning, since QM says nothing about any action or mechanism to enforce correlation between measurements. The simplest position is to treat the quantum state as a non-local, mathematical object that allows you to calulate the probabilities of measurement outcomes. And, sometimes, those probabilities can be 0 or 1.

Again, there has been a common misconception recently that a probability of 0 or 1 somehow contradicts the probabilistic nature of QM. It doesn't. Probabilities of 0 or 1 are precisely what you get in the case of an eigenstate of the measured observable.

 

[Nugatory]

What happens to B in that instant of time?

Quantum Mechanics only describes measurement results, and we haven’t made a measurement yet. As far as QM is concerned, all that we can say about B is that if and when we measure it on the same axis the result will be spin-down. Note that this is not the same thing as saying that B is spin-down.

a) is B still a quantum object and as such doesn't possess definite spin properties before measurement?

That depends on your choice of interpretation.

b) has B the definite property spin-down even prior to its spin measurement?

That also depends on your choice of interpretation.

What means action on a distance in this context, if at all?

It means that we’re speculating about some mechanism (which isn’t part of QM) that could explain (which is not something QM claims to do) why we get the measurement results that QM predicts, and we’re finding it hard to do this without introducing some sort of hypothetical faster-than-light effect in which measuring A changes something about B.

 

[FactChecker]

b) has B the definite property spin-down even prior to its spin measurement?

This seems like asking if there is a local hidden variable, determining the spin of both, that was set before the separation of the particles. That was a great question until Bell's Theorem was proposed and experimental results were obtained.

 

[timmdeeg]

Thanks to everybody for clarifying this question.

I think that's what I've been missing:

The system of two particles is now in an unentangled state. The state of the non-local system has changed, as result of the measurement. The particles are now independent, although each is in an eigenstate of spin about a given axis.

 

[pines-demon]

Two particles, A and B, are entangled. The measurement of A yields spin-up.

What happens to B in that instant of time?

Depends on the interpretation of quantum mechanics. Per relativity of simultaneity, which measurement is performed first depends on the reference frame (for one oberserver A measures first, for another B measures first) so whatever answer has to take this into account.

Some interpretations are:

• Some kind of instantaneous collapse or nonlocal interaction, some kind of influence would travel faster than light but it does not violate relativity because (somehow) it cannot be used for faster-than-light communication. This is the closest we have to action at a distance.
• Something alike many-worlds, where the universe branches from measurements. This creates two universes one where A measured up a B down and one where B measures down and A up. If this happens instantaneously or not, does not seem to matter much because the branching kind of handles the issue.
• Superdeterminism, theories were the measurements and the experiments are somehow part of a big script and the results are pre-determined since the Big Bang. No matter how careful the experimenters are and what the underlying mechanics truly is, the results are always correlated in such a way to reproduce quantum mechanics (conspiracy).
• Retrocausal theories: in the transactional interpretation some kind of signal travels into the past to make sure the results are compatible (shake hand mechanism). Arguably per relativity this is the same as the instantaneous/non-local version.

Note that in some theories like Bohmian mechanics, the spin is not part of the particle but of the wavefunction guiding the particle.

 

[PeterDonis]

What happens to B in that instant of time?

That depends on which interpretation of QM you adopt.

 

[PeterDonis]

Moderator's note: Thread moved to interpretations subforum.

 

[PeterDonis]

The system of two particles is now in an unentangled state.

That's only true for interpretations where collapse is a real process, and which interpret the quantum state as describing individual systems. For interpretations like the MWI (where collapse is not a real process, evolution is always unitary) and statistical interpretations (where the quantum state doesn't describe individual systems, only ensembles), the statement quoted above is not true.

 

[timmdeeg]

Coming back to the term eigenstate,

The system of two particles is now in an unentangled state. The state of the non-local system has changed, as result of the measurement. The particles are now independent, although each is in an eigenstate of spin about a given axis.

There's no problem with a particle being in an eigenstate of spin about a given axis. The measurement of the entangled system has effectively done that to both particles. The spin about other axes is indeterminate - as it would be with any measurement of spin about a given axis.

could you please explain how it relates to the term eigenvalue.

Has a particle in an eigenstate inevitably also an eigenvalue?

 

[PeroK]

Has a particle in an eigenstate inevitably also an eigenvalue?

Yes, an eigenstate of a given observable will result in a definite measurement outcome. The measurement value is the eigenvalue associated with that eigenstate.

 

[timmdeeg]

Thanks!

 

[DrChinese]

There's no problem with a particle being in an eigenstate of spin about a given axis. The measurement of the entangled system has effectively done that to both particles. The spin about other axes is indeterminate - as it would be with any measurement of spin about a given axis.

…

Everything you say around these points is correct. I would emphasize the word “effectively”, because there is a quirk. You measure A and get polarization H, and let’s say that places B into an eigenstate certain to produce V on the same basis.

Q: Are initially polarization entangled PDC photons A and B in the same quantum state (HV?) as 2 PDC produced photons C and D entangled - but not on the polarization basis - which are known to be HV?

A: No! A and B can be used in entanglement swapping, but C and D cannot.

Apparently the “collapse” (or whatever you might imagine) defies even this mechanistic attempt as a description. Photon B is not exactly in the same state as D unless and until it is actually measured on that basis.

Go figure. :)

 

[martinbn]

Go figure. :)

Bohr would have said "Obviously".

 

[timmdeeg]

Quantum Mechanics only describes measurement results, and we haven’t made a measurement yet. As far as QM is concerned, all that we can say about B is that if and when we measure it on the same axis the result will be spin-down. Note that this is not the same thing as saying that B is spin-down.

Do you say that if we don't measure B then it isn't spin-down? It has an eigenvalue but not an eigenstate associated with it.

Is it wrong to say that if we measure A we effectively measure the system consisting of the entangled pair of particles A and B? But if true wouldn't it mean that the outcomes are A has spin-up und B has spin-down?

 

[Morbert]

The system of two particles is now in an unentangled state.

That's only true for interpretations where collapse is a real process, and which interpret the quantum state as describing individual systems. For interpretations like the MWI (where collapse is not a real process, evolution is always unitary) and statistical interpretations (where the quantum state doesn't describe individual systems, only ensembles), the statement quoted above is not true.

Some sharpening of statements is needed here. In MWI, the unitary evolution would apply to the biparticle-and-environment system rather than the biparticle system. The biparticle system (i.e. the system with environmental degrees of freedom traced out) would be in a correlated/anticorrelated state but not an entangled state.

 

[martinbn]

Do you say if we don't measure B then it isn't spin-down? And thus it hasn't an eigenvalue und an eigenstate associated with it.

What does it mean for B to have an eigenvalue?

 

[DrChinese]

1. Quantum Mechanics only describes measurement results, and we haven’t made a measurement yet. As far as QM is concerned, all that we can say about B is that if and when we measure it on the same axis the result will be spin-down. Note that this is not the same thing as saying that B is spin-down.

2. It means that we’re speculating about some mechanism (which isn’t part of QM) that could explain (which is not something QM claims to do) why we get the measurement results that QM predicts, and we’re finding it hard to do this without introducing some sort of hypothetical faster-than-light effect in which measuring A changes something about B.

1. Really well said, as I read this a second time. This seemingly minor detail is the essence of a lesson in QM that is sometimes missed: don’t speculate on the behavior of a quantum system outside of a measurement. (Peres: Unperformed measurements have no results.) This is demonstrated physically by the little quirk I mentioned yesterday.

2. Agree completely: Modern experiments make holding on to locality so difficult, I have finally tipped over the edge on this point. However, I lack any concept of an underlying mechanism - everything I’ve read as possible explanations appears to be ruled out by one experiment or another.

 

[PeterDonis]

In MWI, the unitary evolution would apply to the biparticle-and-environment system rather than the biparticle system.

And the measuring device. The entanglement first spreads to the measuring device when the measurement takes place, and then to the environment as decoherence takes place.

The biparticle system (i.e. the system with environmental degrees of freedom traced out) would be in a correlated/anticorrelated state but not an entangled state.

Wrong. The biparticle system becomes entangled with the measuring device and the environment. It never goes to a non-entangled state. The entanglement between the two particles themselves is no longer maximal, because the entanglement spreads to more and more degrees of freedom, but the particles are never in a non-entangled state.

 

[timmdeeg]

What does it mean for B to have an eigenvalue?

It means, that in the case of B's measurement B has an eigenstate associated with that eigenvalue.

 

[Morbert]

And the measuring device. The entanglement first spreads to the measuring device when the measurement takes place, and then to the environment as decoherence takes place.

I include the measuring device in the environment but we can demarcate the two if needed later.

Wrong. The biparticle system becomes entangled with the measuring device and the environment. It never goes to a non-entangled state. The entanglement between the two particles themselves is no longer maximal, because the entanglement spreads to more and more degrees of freedom, but the particles are never in a non-entangled state.

Consider a biparticle-and-environment system initially in the state $\frac{1}{\sqrt{2}}(\ket{00}+\ket{11})\ket{\epsilon_\Omega}$. After measurement the system is in the state $\frac{1}{\sqrt{2}}(\ket{00}\ket{\epsilon_0}+\ket{11}\ket{\epsilon_1})$. The biparticle system is in the state$$\mathrm{tr}_\epsilon \rho = \frac{1}{2}(\ket{00}\bra{00} + \ket{11}\bra{11})$$which is an unentangled state.

 

[PeterDonis]

It means, that in the case of B's measurement B has an eigenstate associated with that eigenvalue.

But you were talking about a case where B has not been measured.

 

[timmdeeg]

But you were talking about a case where B has not been measured.

In more detail, supposed A has been measured, but B not yet. In this case B has an eigenvalue, but depending on the interpretation not an eigenstate. In this case if B is measured thereafter B will have an eigenstate associated with said eigenvalue.

 

[PeterDonis]

In more detail, supposed A has been measured, but B not yet. In this case B has an eigenvalue

No, it doesn't. Until B is measured it has no eigenvalue. Remember that until B is measured, you can't dictate in what direction its spin is being measured--which you would have to do to assign it an eigenvalue.

 

[Fra]

2. Agree completely: Modern experiments make holding on to locality so difficult

For me they rather make holding onto objective reality (realism) difficult if not impossible

lack any concept of an underlying mechanism - everything I’ve read as possible explanations appears to be ruled out by one experiment or another.

Especially if the "mechanism of interactions between parts" one seeks must necessarily be formulated in terms of functions of objective beables; wether deterministically or probabilistically , then I agree a mechanism seems impossible.

/Fredrik

 

[DrChinese]

For me they rather make holding onto objective reality (realism) difficult if not impossible

I agree with this too. I was formerly of the view that Local Realism is untenable (due to Bell's Theorem). But with more and more experiments: Both Realism (basically contradicted by the HUP anyway) and Einsteinian Locality (denying remote effects of any kind) seem untenable.

(And every hypothetical mechanism for nonlocality seems equally untenable LOL.)

 

[Fra]

I agree with this too. I was formerly of the view that Local Realism is untenable (due to Bell's Theorem). But with more and more experiments: Both Realism (basically contradicted by the HUP anyway) and Einsteinian Locality (denying remote effects of any kind) seem untenable.

(And every hypothetical mechanism for nonlocality seems equally untenable LOL.)

I have not yet seen any compelling reason for abandoning Einsteinian Locality(*).

I see hope in understanding thing while keeping a notion of locality, in terms of subjective reality or "subjective beables" where "mechanism of interactions between parts" takes on other forms that presumed in "local realism", because unlike objective beables, they do not commute, so you can't make a conceptually sound partition, or divisions that Barandes speaks of conditional probablities in terms of a mixed of incompatible beables.

Sometime there seems to be a funny relation between "objective" vs "global" and "subjective" vs "local", as it is what defines the relations between "parts", either by some "position" in a space, or "position" in information space.

(*) Except the obvious that at some point when we get into QG, spacetime itself maybe reformulated, then notions defined in terms of them such as locality needs be reformulated too)

/Fredrik

 

[Fra]

(And every hypothetical mechanism for nonlocality seems equally untenable LOL.)

Here we 100% agree as well!

/Fredrik

 

[timmdeeg]

No, it doesn't. Until B is measured it has no eigenvalue. Remember that until B is measured, you can't dictate in what direction its spin is being measured--which you would have to do to assign it an eigenvalue.

Ah, yes, thanks. I have confused eigenstate and eigenvalue. So, until B is measured it has an eigenstate of spin. Correct?

 

[pines-demon]

Ah, yes, thanks. I have confused eigenstate and eigenvalue. So, until B is measured it has an eigenstate of spin. Correct?

There is no eigenstate of spin in the sense that spin is not an observable by itself. What you can observe are projections of spin in given directions of space. So if Alice measures spin in some axis, the particle of B is going to be in an eigenstate of the projection of spin only in that same axis.

 

[PeterDonis]

Ah, yes, thanks. I have confused eigenstate and eigenvalue. So, until B is measured it has an eigenstate of spin. Correct?

It depends on what you mean. Please read my post again, carefully.

 

[martinbn]

Einsteinian Locality (denying remote effects of any kind) seem untenable.

Why is that untenable? And what exactly is a remote effect?

 

[DrChinese]

Why is that untenable? And what exactly is a remote effect?

Entanglement Swapping/Quantum Teleportation are remote effects. Obviously, there are interpretations that attempt to retain locality in the face of this. But most of those interpretations are needing progressively more convoluted descriptions to accommodate Swapping experiments while maintaining something they call "locality".

An example of that is MWI, which now appears to require something resembling "global" splitting of worlds in order to make sense of swapping. How else to explain that there is syncing of observation results of particles that have never been in a common area of spacetime?

Similarly, for interpretations that do not posit the Swap (Bell State Measurement) as being physical: How to explain the "revealing" of correlations of independently produced systems? (As noted in these experiments themselves, those systems were previously uncorrelated before the swap.)

Each person is free to view the various arguments as they like. (And I am constantly surprised at how many people essentially even advocate Local Realistic explanations in the face of Bell.) For me: Swapping experiments are the nail in the coffin for locality.

 

[Fra]

I think we share an underlying desired to understand or find a mechanism, but we currently have very different ideas and thinking... this is why i liket it where we can at least agree on something as it makes discussions more constructive than more "confrontative". Just concluding that we disagree or think differently is not leading to progress.

(And I am constantly surprised at how many people essentially even advocate Local Realistic explanations in the face of Bell.) For me: Swapping experiments are the nail in the coffin for locality.

Are you by any chance lumping Barandes ideas into these "people"?

/Fredrik

 

[martinbn]

Entanglement Swapping/Quantum Teleportation are remote effects. Obviously, there are interpretations that attempt to retain locality in the face of this. But most of those interpretations are needing progressively more convoluted descriptions to accommodate Swapping experiments while maintaining something they call "locality".

An example of that is MWI, which now appears to require something resembling "global" splitting of worlds in order to make sense of swapping. How else to explain that there is syncing of observation results of particles that have never been in a common area of spacetime?

Similarly, for interpretations that do not posit the Swap (Bell State Measurement) as being physical: How to explain the "revealing" of correlations of independently produced systems? (As noted in these experiments themselves, those systems were previously uncorrelated before the swap.)

Each person is free to view the various arguments as they like. (And I am constantly surprised at how many people essentially even advocate Local Realistic explanations in the face of Bell.) For me: Swapping experiments are the nail in the coffin for locality.

No, my question was why is Einstein locality untenable? Everyone agrees about Bell non-locality.

 

[sahashmi]

I agree with this too. I was formerly of the view that Local Realism is untenable (due to Bell's Theorem). But with more and more experiments: Both Realism (basically contradicted by the HUP anyway) and Einsteinian Locality (denying remote effects of any kind) seem untenable.

(And every hypothetical mechanism for nonlocality seems equally untenable LOL.)

The HUP does not contradict realism. It simply says that we can’t simultaneously measure two different properties of something physical. And even if certain properties at measurement are merely contextual, it just means that what we measure depends on what we measure. This is a trivial point and has nothing to say about objective reality. It merely means that we don’t know how to describe objective reality before measurement.

 

[Sambuco]

The HUP does not contradict realism

I believe @DrChinese is referring to realism as something like "the system has well-defined properties independent of measurements" (correct me @DrChinese if I misunderstood you).

It simply says that we can’t simultaneously measure two different properties of something physical

I think this is wrong in the sense that the HUP only states that, for two non-commuting observables, there is no quantum state that determines, i.e. predicts with probability one, the outcome of each of the two measurements.

Lucas.

 

[Sambuco]

I agree with this too. I was formerly of the view that Local Realism is untenable (due to Bell's Theorem). But with more and more experiments: Both Realism (basically contradicted by the HUP anyway) and Einsteinian Locality (denying remote effects of any kind) seem untenable.

(And every hypothetical mechanism for nonlocality seems equally untenable LOL.)

That also reflects how my understanding of this topic has changed over time. Your last statement explains why, today, I believe that the experimental verification of the violation of Bell's inequality and the evidence of remote entanglement swapping strongly point against the notion of causation at a fundamental level.

Lucas.

 

[Morbert]

There are a good few well-established projects in foundations of quantum mechanics that preserve Einstein locality and statistical independence for all known experiments: E.g. Instrumentalism, minimal Statistical, Oxford Everettianism, Decoherent/Consistent Histories, topos-theoretic interpretations, and QBism.

There is also no consensus about the correctness of any project in foundations of quantum mechanics.

 

[DrChinese]

Are you by any chance lumping Barandes ideas into these "people"?

It depends on the day of week for my lumping him in with those writers, as well as even a few posters here.

We already know Barandes' view on locality: "...Causally Local Formulation of Quantum Theory". What he says on realism is not clear to me: "Moreover, superposition is no longer a literal smearing of configurations, interference is just a breakdown in divisible dynamics, and decoherence is merely the leakage of statistical correlations out into the larger environment." (That's word salad to me.) Whenever I hear someone using the term "stochastic", I immediately think they are a realist at their core.

We had a long discussion about Mjelva's paper. He seems to be a local realist without saying so. Many others as well, I have a lot of bookmarks to papers of that type (Christian, Laudisa, Sica, Santos, De Raedt, etc.). Most identify an element of Bell that they can claim is "wrong" in some manner, so as to avoid the Bell conclusion.

 

[DrChinese]

I believe @DrChinese is referring to realism as something like "the system has well-defined properties independent of measurements" (correct me @DrChinese if I misunderstood you).


I think this is wrong in the sense that the HUP only states that, for two non-commuting observables, there is no quantum state that determines, i.e. predicts with probability one, the outcome of each of the two measurements.

Lucas.

Correct, you can also call it objective reality or non-contextual reality.

The obvious point about the HUP: It is a prima facie case for rejecting realism. Of course, realists will inevitably point to its application to experimental results - but HUP does not represent the underlying reality. But that's pretty close to saying a horse is actually a unicorn in disguise. You can say that about almost anything.

Ditto for attempts to ignore the obvious signs of "action at a distance" in Entanglement Swapping experiments. "It might look like nonlocality, but it isn't." Or maybe things are exactly as they appear at first blush.

 

[physika]

realism as something like the system has well defined properties independent of measurements

Realism is more than that, is not simply about properties.
Which things/entities have that
properties ?

.....

 

[martinbn]

Ditto for attempts to ignore the obvious signs of "action at a distance" in Entanglement Swapping experiments. "It might look like nonlocality, but it isn't." Or maybe things are exactly as they appear at first blush.

To me it doesn't look like "action at distance". In fact it doesn't look like any kind of action at all. I know that to some it looks like it, and for some (you for example) it is unconditionally proven, but I think you are wrong.

 

[PeterDonis]

the obvious signs of "action at a distance" in Entanglement Swapping experiments. "It might look like nonlocality, but it isn't."

"Nonlocality" and "action at a distance" are not the same thing.

Nonlocality, if by that we mean violations of the Bell inequalities, is an experimental fact---and since you're relying on experimental facts for your argument, that's the definition of "nonlocality" you are implicitly using.

"Action at a distance" is a feature of some QM interpretations (including the QM interpretation you are implicitly using), but not all. It is of course possible that at some point, we will have a more comprehensive theory, with experimental support, to which our current QM is an approximation, that will have "action at a distance" as an explicit part of its dynamics, and will tell us how to confirm experimentally that this "action at a distance" actually happens. But we don't have any such theory now, and in the absence of one, claims about "action at a distance" are interpretation dependent, and therefore are not resolvable by experiment; they're a matter of personal opinion.

 

[Fra]

I think it's the fact that we do not have (one way or the other) any explanatory mechanisms, that some of just accept, and some of use refuse to settle with that is one difference.

It seems to me that Dr Chinese can't accept this, and neither can I. So I symphatise with that.

But "explanation" can come in different forms, Bells theorem provides a no-go theorem for certain types of explanation in terms of "objective beables", which would explain "quantum phenomena" by marginalise them out.

But the quest for an explanation does not end with that. It only means that a viable explanation has to evade some of the premises.

Dr Chinese's thinking seems to currently lean strongly towards some explanation in terms of action at distance, probably not because it make so much sense, but because he seems to see no other solution in the face of entanglement swapping + bells theorem? Have I understood you here?

And then to those that say, that this makes no sense, it's fair to ask: What is the better idea?

/Fredrik

 

[Fra]

Whenever I hear someone using the term "stochastic", I immediately think they are a realist at their core.

Do you see the difference in the Bell type stochastics which is marginalising over objective hidden variables that influence the total system dynamics (via dynamical law)? and the stochastics over subjective hidden variables which is identified with the irreducible stochastic law? There is no objective margninalization going on in Barandes stochastics; it's irreducible.

Why that is satsifactory to me is that (expcet that the timeevolution of the matrices needs to be explained from new first princuipoes) a stochastic law, is as simple as it gets, and the only law thay need no further explanation.

After all, it's not the randomness of outcomes in QM that we seek to explain - this is indeed I think irreducible - it's all about the correlaction of remote experiments. Barandes view does not restore determinsim, via margnialized HV.

/Fredrik

 

[DrChinese]

"Nonlocality" and "action at a distance" are not the same thing.

Nonlocality, if by that we mean violations of the Bell inequalities, is an experimental fact---and since you're relying on experimental facts for your argument, that's the definition of "nonlocality" you are implicitly using.

"Action at a distance" is a feature of some QM interpretations (including the QM interpretation you are implicitly using), but not all. …

I think your differentiation of “nonlocal” and “action at a distance” is fair.

I usually employ AAAD as a term to reference something that is interpretation dependent. But I also use the word “distance” in the phrase to refer to distance in spacetime, and in ways that could be considered to defy Einsteinian causality. There is a somewhat analogous usage in the word “nonlocality”, going back to various delayed choice type experiments. For example: entanglement of particles that never coexist.

So when we are trying to put together a storyline about what is going on beneath the hood, regarding the (factual) nonlocality of experiments, we are necessarily speculating when adopting an interpretation.

I believe the factual conclusions of many cited experiments can be assembled into a more comprehensive narrative that rules out many popular interpretations. I know this won’t convince most advocates of those interpretations. But it is fair to challenge those viewpoints if I lead with accepted science.

claims about "action at a distance" are interpretation dependent, and therefore are not resolvable by experiment; they're a matter of personal opinion.

I’ve been pretty clear that each person is free (within everything I reference in the way of experiments) to hold their own views. Here in the interpretations forum it is common to profess a perspective and explain its pros and hopefully, its cons.

 

[PeterDonis]

I believe the factual conclusions of many cited experiments can be assembled into a more comprehensive narrative that rules out many popular interpretations.

Such a "narrative", if it actually did what you claim, would be the sort of more comprehensive theory that I described, to which our current QM would be an approximation. In other words, it would make experimental predictions that current QM does not make, which would be true if the "narrative" was true, but false if it was not--so that the claim could actually be checked.

But as far as I know, no such thing actually exists. Nobody has a more comprehensive model that makes actual predictions that go beyond the standard predictions of QM, enabling an experimental test of the model, where those tests have actually come out as predicted. (There are examples of alternate theories to standard QM, such as the GRW stochastic collapse model, but all of them so far have been falsified by experiments; their predictions haven't worked.)

it is fair to challenge those viewpoints if I lead with accepted science.

But you're not doing that; you're leading with a claim about possible future science that doesn't currently exist. See above.

Our current "accepted science" simply cannot distinguish between the various interpretations that are out there. That's why, while it's fine to state your preferred interpretation and its pros and cons in this forum, it's not fine to claim that other interpretations are ruled out by experiment. That's simply not the case. All QM interpretations make the same experimental predictions. You might not like how some of them get there, but that's a matter of personal opinion.

 

[DrChinese]

1. DrChinese's thinking seems to currently lean strongly towards some explanation in terms of action at distance, probably not because it make so much sense, but because he seems to see no other solution in the face of entanglement swapping + bells theorem? Have I understood you here?

2. And then to those that say, that this makes no sense, it's fair to ask: What is the better idea?

1. You hit the nail on the head.

2. Correct here too. Keeping in mind that AAAD is for me a bucket that includes all those ideas other than the usual interpretations, but that are pretty well expressed in orthodox QM:

There is a saying attributed to Sherlock Holmes: “When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.”

For example: retrocausal (they go under a lot of names) interpretations might have utility. (I’m not pushing that in particular.)

I’m just saying: We’ve been examining Bohmian ideas since the 40’s and Everettian ideas since the 50’s and have so far got zilch from either. And I believe there’s now sufficient accepted evidence to rule out both of those. But that’s simply my opinion and assessment.

 

[DrChinese]

All QM interpretations make the same experimental predictions. You might not like how some of them get there, but that's a matter of personal opinion.

No, they all claim to make the same predictions. Each has assumptions that are fair to challenge. This forum is the place to discuss within the context of a specific idea.

This thread is about AAAD, but believe me I don’t want to derail others expressing their ideas. I am just one voice. I’ve probably said enough for today…