I CFD - Counterfactual Definiteness

[Eye_in_the_Sky]

Now you're talking about the "state of the instruments," being "nonseparable" so I assume you're talking about the instruments in terms of being in a quantum state. I don't know what else you mean. If so, you need an interpretation of QM to discuss the situation ontologically because you have to deal with the measurement problem.

I may be having a conceptual difficulty.

To my understanding, the following conjunction is not logically possible:

each one's outcome is 'nonseparable' from the setting of the other

AND

the joint-state of their instruments is 'separable' .

Is that logically possible? ... for both statements to hold?

 

[bhobba]

each one's outcome is 'nonseparable' from the setting of the other
the joint-state of their instruments is 'separable' .

You are making it all way harder than it really is.

All Bell is saying is if you want the outcomes of measurements to be independent of the measurement then you need FTL.

The following CAREFULLY explains the issues and terms:
http://www.johnboccio.com/research/quantum/notes/paper.pdf

Thanks
Bill

 

[Simon Phoenix]

Each one's outcome is 'nonseparable' from the setting of the other; therefore, the joint-state of their instruments is 'nonseparable'.

Eye,

I've no idea where you're going with all of this and I think you're making things more complicated than they need to be.

Let's backpedal a bit and think about what the Bell analysis is all about. Let's pretend that QM hasn't been invented yet. We know nothing about 'separable' or 'non-separable' or 'wavefunctions'.

Now we have some experiment consisting of 2 pieces of measuring kit and some source. So in the usual fashion we arrange them like so
A <---------- S ----------> B
We can adjust the dial on the kit to measure at settings a,b, or c.
The outcome is just a single binary value 1 or 0 (a ping or a ding)

Everything is at 'black box' level. The only data we can record at each measuring station, for each timeslot, is the setting (a,b, or c) and the binary value obtained.

Our job is to see whether any correlations that might be observed can be explained at this very general level in terms of probability distributions that can actually be measured in this experiment.

So we quite naturally make the assumption that whatever the source is doing or generating (fields, particles, little green tribbles, etc) there are going to be some variables that will explain any correlation. We might not have any control of or access to these variables, but we assume they are underlying things and giving rise to the correlation. Furthermore we quite naturally assume that these variables are such that they have some existence independent of the measurement.

Now, it would be strange if A and B were miles apart and the results (the ping or ding) recorded at A depended in some way on the position of the dial (a,b or c) that had been chosen at B.

Let's call these kinds of variables 'classical-like' - they have properties that are very natural and reasonable. They exist outside of measurement, for one, and they don't bugger up relativity.

Now we write down the various conditional probabilities we have, do some manipulations, and find that there's a constraint on certain functions that can actually be measured in this experiment. So we know that ANY theory that utilises these kinds of variables must give predictions within these constraints.

We do the experiment and find that the results we get don't satisfy this constraint. So whatever is happening (fields, particles or tribbles) it cannot be described by a theory of this kind using these kinds of classical-like variables.

As soon as you want to try to describe things in terms of variables that have some existence independent of measurement (like everyday classical variables such as position or momentum or field strength and so on) then if you want to explain the observed results those variables have to have some non-local connection - crudely put, there must be some mechanism that transfers 'information' about settings at A to the system (kit plus tribble) at B in a way that buggers up relativity. You can't actually communicate FTL, in the sense that A and B can't use this to exchange information, but quite clearly real information about whether A has chosen a,b or c must be, in some sense 'accessible' to the kit plus tribble at B if we want to have our variables have some meaning independent of experiment.

So when you talk of the kit being 'non-separable' are you trying to understand things in terms of variables that have some objective existence outside of measurement and using 'non-separable' to describe this necessary 'information transfer mechanism'? Or do you mean something more akin to the non-separability described by QM?

 

[Simon Phoenix]

Each one's outcome is 'nonseparable' from the setting of the other; therefore, the joint-state of their instruments is 'nonseparable'.

Let's look at this from the QM perspective,

We'll model the experimental kit, the measuring devices, as quantum objects. The initial state of the correlated particles plus measuring devices is then given by

[ |10> + |01> ] ⊗ |A_initial> |B_initial>

where I'm ignoring normalization. So the particles are entangled, but the measuring devices are uncorrelated (and separable). They're not correlated to one another and nor are they correlated with the particles we're going to measure.

After the particles have interacted with the devices, but before the measurement is performed, the state evolves to

|10> |A₁>|B₀> + |01> |A₀>|B₁>

So the state of the particles plus measuring devices is entangled (or non-separable in the QM sense).

The state of the measuring devices alone is given by the density operator (non-normalized)

ρ = |A₁, B₀><A₁, B₀| + |A₀, B₁><A₀, B₁|

which is a correlated but not entangled state

So once the particles have interacted with the devices (but before the measurement) we can't 'separate' the particles plus devices.

You're trying to draw some conclusions about the measuring devices alone, in terms of non-separability, but that's not going to work within the QM picture of things.

I'm just repeating what RUTA has been trying to tell you using the QM formalism.

 

[RUTA]

I may be having a conceptual difficulty.

To my understanding, the following conjunction is not logically possible:

each one's outcome is 'nonseparable' from the setting of the other

AND

the joint-state of their instruments is 'separable' .

Is that logically possible? ... for both statements to hold?

Yes, the instruments are classical but the outcomes they register are described by a quantum state that depends on the settings of those instruments in nonseparable (assuming causal locality) fashion.

 

[Eye_in_the_Sky]

Yes, the instruments are classical but the outcomes they register are described by a quantum state that depends on the settings of those instruments in nonseparable (assuming causal locality) fashion.

Okay, RUTA ... I will go with that too. Thus, I am placed into a 'corner' with one last claim to make.
____

Suppose there is no violation of 'causal locality'. Then:

If we say that the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B, then we are forced to say

The 'quantum state' is PHYSICAL.

... Can we agree on that?

 

[RUTA]

Okay, RUTA ... I will go with that too. Thus, I am placed into a 'corner' with one last claim to make.
____

Suppose there is no violation of 'causal locality'. Then:

If we say that the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B, then we are forced to say

The 'quantum state' is PHYSICAL.

... Can we agree on that?

That depends on your interpretation of QM. You're certainly not forced to say that.

 

[morrobay]

I may be having a conceptual difficulty.

To my understanding, the following conjunction is not logically possible:

each one's outcome is 'nonseparable' from the setting of the other

Just regarding above and restate from previous.
Case 1: With non parallel settings a & b calculate QM predictions for spin 1/2 particles, P++ = P -- = 1/2 ( sin θ/2 ) ²
θ = a-b. Then do experiment
Case 2: Change setting at A, a >> a' and calculate predictions for P++ and P-- with θ = a'-b and do experiment.
If QM prediction in case 2 match results for case 2 then outcome at Bb
was not influenced and separable from setting change at A, a >> a'
If predictions in case 2 do not match results for settings in case 2 then there is a question:
" An influence on the very conditions which define the possible types of predictions regarding the future behavior of the system "
Ie: Outcome at B was influenced and non separable from setting change at A, a>>a'
The other option is giving up CFD. Then a superluminal influence does not apply in explaining result

 

[bhobba]

The 'quantum state' is PHYSICAL.

That is VERY interpretation dependent.

Here, for example, is the view of the Baysians:
https://www.quantamagazine.org/20150604-quantum-bayesianism-qbism/

QM is a morass of things that are difficult or impossible to pin down exactly.

Thanks
Bill

 

[Eye_in_the_Sky]

That depends on your interpretation of QM. You're certainly not forced to say that.

That is VERY interpretation dependent.

Ok ... Ok. I will have to recast my claim.

 

[Eye_in_the_Sky]

I've no idea where you're going with all of this ...

I was trying to resolve the dispute below:

Bhobba contends that the quantum correlations are compatible with both of these conditions taken together:

1) The joint state of Alice's measuring instrument and Bob's measuring instrument, in spacetime, is separable.

2) Their measuring instruments are mutually non-influencing.

I am saying that (at least) one of these conditions needs to be relinquished.

The dispute has now been resolved to my satisfaction. Bhobba is correct.

My contention was based upon a misconception. I was not properly distinguishing between these two distinct notions:

(i) The joint-state of X and Y is 'nonseparable'.

(ii) The 'separable' states of X and Y are 'nonseparably' connected.
__________

I will write (ii) as (2) and particularize X and Y to the instruments of Alice and Bob. I will also put that statement up for comparison with a similar looking statement that I will designate as (1):

(1) The 'separable' states of their instruments are 'causally' connected.

(2) The 'separable' states of their instruments are 'nonseparably' connected.

I'm not at all sure that the violation of the mathematical inequality has anything to do with locality (or non-locality) in QM.

First off, I think it's important to be clear about what is meant by 'locality' because this has different meanings in different contexts. What I mean by 'locality' in the context of the Bell inequality, and in an intuitive sense, is the following : the results of experiments 'here' are not affected by the settings of devices 'there'. [Or if they are, any such influence cannot travel faster than the speed of light]

Permit me to paraphrase your statement of LOCALITY as:

Bob's setting does not AFFECT Alice's outcome.

There is a problem with this statement. The word "affect" pertains to matters of 'causality'. But statement (2) above is talking about an 'acausal' connection. To say that Bob's setting is 'nonseparably' connected to Alice's outcome means that the setting and the outcome DO NOT even STAND in a 'cause' and 'effect' RELATIONSHIP; and if that is so, then it is TRUE BY DEFINITION that Bob's setting DOES NOT AFFECT Alice's outcome.

The diction is faulty.

Here is the set of definitions I am using for 'causality':

effect: a 'state of affairs' that is brought about by a 'cause'

affect: to act, in a manner of 'causation', so as to produce an 'effect'

influence: the agency through which an 'effect' is established

causation: the relationship between 'cause' and 'effect'

causality: the notion of 'causation'

Thus, to repeat, as you can see, (by definition) an 'effect' can NEVER HAPPEN if the RELATIONSHIP is ACAUSAL.

This fault in diction, however, is simple to correct – just rewrite the above statement of LOCALITY as:

Bob's setting is IRRELEVANT to Alice's outcome.

How, then, in this context is IRRELEVANT to be understood?

It means (roughly) this:

The 'physics in play' at Alice's station can be ASSUMED to be the same regardless of what Bob's setting happens to be.

This idea requires explanation.

 

[Eye_in_the_Sky]

As soon as you want to try to describe things in terms of variables that have some existence independent of measurement (like everyday classical variables such as position or momentum or field strength and so on) then if you want to explain the observed results those variables have to have some non-local connection - crudely put, there must be some mechanism that transfers 'information' about settings at A to the system (kit plus tribble) at B in a way that buggers up relativity. You can't actually communicate FTL, in the sense that A and B can't use this to exchange information, but quite clearly real information about whether A has chosen a,b or c must be, in some sense 'accessible' to the kit plus tribble at B if we want to have our variables have some meaning independent of experiment.

So when you talk of the kit being 'non-separable' are you trying to understand things in terms of variables that have some objective existence outside of measurement and using 'non-separable' to describe this necessary 'information transfer mechanism'? Or do you mean something more akin to the non-separability described by QM?

Hi, Simon. Right now, this is the very best I can do to explain myself.
______

In each run of the experiment:

At least one of the instruments must 'know' both the setting and the outcome of the other instrument.

Otherwise, the quantum correlations cannot happen.

But, how did that 'information' get there?

If we say that the 'information' got there via a 'causal' connection (i.e. through the agency of an 'influence'), then we are forced to say it is FTL.

On the other hand,

If we say that the 'information' quite simply is there in virtue of a 'nonseparable' connection (i.e. with no 'agent' acting within spacetime to bring over the 'information')

... then are we still not forced, nonetheless, to say that the connection is NONLOCAL?

I think so. I think everybody else should think so.

Simon, what do you think? ... What about everybody else?

 

[RUTA]

Hi, Simon. Right now, this is the very best I can do to explain myself.
______

In each run of the experiment:

At least one of the instruments must 'know' both the setting and the outcome of the other instrument.

Otherwise, the quantum correlations cannot happen.

But, how did that 'information' get there?

If we say that the 'information' got there via a 'causal' connection (i.e. through the agency of an 'influence'), then we are forced to say it is FLT.

On the other hand,

If we say that the 'information' quite simply is there in virtue of a 'nonseparable' connection (i.e. with no 'agent' acting within spacetime to bring over the 'information')

... then are we still not forced, nonetheless, to say that the connection is NONLOCAL?

I think so. I think everybody else should think so.

Simon, what do you think? ... What about everybody else?

It sounds like you're imagining a spacelike "link" between the measurement outcome events. Such a "link" would constitute "nonlocality" in the FTL sense. You can avoid drawing such a spacelike link in the nonseparable/holistic view of the events if you include the emission event and connect the emission event with the two detection events by timelike links and consider THAT collection of events to be nonseparable. That's called retrocausality.

 

[Simon Phoenix]

At least one of the instruments must 'know' both the setting and the outcome of the other instrument.

OK - in the post of mine you've quoted above there's a very important 'if' in there. Let's just re-state the position.

IF we want to describe things with variables that have a realistic character THEN we require some non-local (FTL) properties for them, in order to use them to explain the violation of the Bell inequality. There's no escape, no ifs or buts, we are forced into this once we assume this realistic character.

But if one adopts a QM view of things is one forced to think in terms of non-local effects or processes?

Not at all - it rather depends on the interpretation of QM you choose to work with. Have a look at the "Gell Mann on entanglement" thread. Vanhees beautifully explains a consistent interpretation of QM that requires no such 'non-local' thinking to explain what's happening. I'm not fully happy with any interpretation of QM - although I tend to most often think in terms of state collapse where the state has some ontic character - although there are serious problems with this perspective.

Ultimately, so far, ANY of the interpretations of QM will predict the violation - each one will have a different way of 'explaining' it. There is no way, at the moment, that we can say we are forced to adopt any of these particular interpretations as being the 'correct' one.

 

[morrobay]

Here is the spacelike separated setup with detectors A and B about 20 km apart.
I would just ask the question: What is the explanation for the non classical correlations that violate
Bell inequalities that do not include any superluminal signaling in any aspect of experiment ?
Was this information en coded into the entangled particles at the source during their creation ?
What exactly are non local quantum correlations that again are relativistic ?
How does the vanhees71 interpretation answer this at the B level ?

 

[Zafa Pi]

Here is the spacelike separated setup with detectors A and B about 20 km apart.
I would just ask the question: What is the explanation for the non classical correlations that violate
Bell inequalities that do not include any superluminal signaling in any aspect of experiment ?
Was this information en coded into the entangled particles at the source during their creation ?
What exactly are non local quantum correlations that again are relativistic ?
How does the vanhees71 interpretation answer this at the B level ?

The answer to your 1st ? is: There is none. That is Gell-Mann's position and I've not seen anything that convinces me otherwise.*
The answer to your 2nd ? is: No. That would be hidden variables which the violation of Bell's inequality proves is false.
My answer to your 3rd ? is: I'm skeptical like you.

*There are classical phemonena with no explanation as well.

 

[Zafa Pi]

The answer to your 1st ? is: There is none. That is Gell-Mann's position and I've not seen anything that convinces me otherwise.*
The answer to your 2nd ? is: No. That would be hidden variables which the violation of Bell's inequality proves is false.
My answer to your 3rd ? is: I'm skeptical like you.

*There are classical phemonena with no explanation as well.

Actually I like Einstein's answer to the 1st ?: Spooky action at distance.

 

[RUTA]

IF we want to describe things with variables that have a realistic character THEN we require some non-local (FTL) properties for them, in order to use them to explain the violation of the Bell inequality. There's no escape, no ifs or buts, we are forced into this once we assume this realistic character.

You can have locality and realism (CFD) with retrocausality. Of course the CFD is irrelevant given the outcomes and settings are part of the ontological explanation. But, you can paint whatever properties you like on the worldlines in retrocausality and all connections are timelike (no FTL properties). You just have to be willing to consider spatiotemporal (block universe) explanation as fundamental, what Wharton calls Lagrangian Schema explanation (based on least action principles), rather than time-evolved dynamical explanation (mechanical universe), what Smolin calls Newtonian Schema explanation (based on differential equations). This idea is perhaps in keeping with Wilczek's challenge:

A recurring theme in natural philosophy is the tension between the God’s-eye view of reality comprehended as a whole and the ant’s-eye view of human consciousness, which senses a succession of events in time. Since the days of Isaac Newton, the ant’s-eye view has dominated fundamental physics. We divide our description of the world into dynamical laws that, paradoxically, exist outside of time, and initial conditions on which those laws act. The dynamical laws do not determine which initial conditions describe reality. That division has been enormously useful and successful pragmatically, but it leaves us far short of a full scientific account of the world as we know it. The account it gives – things are what they are because they were what they were – raises the question, Why were things that way and not any other? The God’s-eye view seems, in the light of relativity theory, to be far more natural. Relativity teaches us to consider spacetime as an organic whole whose different aspects are related by symmetries that are awkward to express if we insist on carving experience into time slices. Hermann Weyl expressed the organic view memorably in his 1949 book \textit{Philosophy of Mathematics and Natural Science} (Princeton University Press, page 116):

The objective world simply is, it does not happen. Only to the gaze of my consciousness, crawling upward along the life line of my body, does a section of this world come to life as a fleeting image in space which continuously changes in time.

To me, ascending from the ant’s-eye view to the God’s-eye view of physical reality is the most profound challenge for fundamental physics in the next 100 years.

Wilczek, F.: Physics in 100 Years. Physics Today 69(4), 32-39 (2016).

 

[Eye_in_the_Sky]

OK - in the post of mine you've quoted above there's a very important 'if' in there. Let's just re-state the position.

IF we want to describe things with variables that have a realistic character THEN we require some non-local (FTL) properties for them, in order to use them to explain the violation of the Bell inequality. There's no escape, no ifs or buts, we are forced into this once we assume this realistic character.

But if one adopts a QM view of things is one forced to think in terms of non-local effects or processes?

Not at all - it rather depends on the interpretation of QM you choose to work with.

Ah, yes. ... I think I see our point of disagreement.

Consider the statement:

At least one of the instruments KNOWS THE VALUE of both the setting and the outcome of the other instrument.

I am saying that this statement is true no matter what. Otherwise, the quantum correlations cannot happen as they do.

You are saying that when we employ 'realistic variables' in the description, we are forced to accept such a statement. But when we don't do that, the matter is left open and it depends upon interpretation.

... Did I get that right?
_______

Have a look at the "Gell Mann on entanglement" thread. Vanhees beautifully explains a consistent interpretation of QM that requires no such 'non-local' thinking to explain what's happening.

Does anyone have a link to that post?

 

[morrobay]

Ah, yes. ... I think I see our point of disagreement.

Consider the statement:

At least one of the instruments KNOWS THE VALUE of both the setting and the outcome of the other instrument.

I am saying that this statement is true no matter what. Otherwise, the quantum correlations cannot happen as they do.

You are saying that when we employ 'realistic variables' in the description, we are forced to accept such a statement. But when we don't do that, the matter is left open and it depends upon interpretation.

... Did I get that right?
_______

Does anyone have a link to that post?

 

[Simon Phoenix]

You can have locality and realism (CFD) with retrocausality

Yes, that's a good point - I think that makes intuitive sense.

 

[Simon Phoenix]

≠

At least one of the instruments KNOWS THE VALUE of both the setting and the outcome of the other instrument.

I am saying that this statement is true no matter what. Otherwise, the quantum correlations cannot happen as they do.

You are saying that when we employ 'realistic variables' in the description, we are forced to accept such a statement. But when we don't do that, the matter is left open and it depends upon interpretation.

... Did I get that right?

Sort of - but I think there's always going to be a struggle pinning everything down with 'precise enough' words. In my opinion we do have to be a bit careful using words like 'know' and even 'information'. I've tried to be careful about this in my posts above so that I would say that in a realistic variable treatment the information about what's happening at B has to be in some sense available to A. And here I'd hope that the use of 'in some sense' would indicate that I'm not being overly precise but rather attempting to convey an intuition.

If we had some probability distribution P(X,Y) where X and Y are 2 random variables then we could determine from this the various marginal and conditional probabilities, like P(X | Y), for example. If X and Y are completely uncorrelated then we have that
P(X) = P(X | Y). In information terms we would say that information about Y gives us no information about X. If they were correlated so that
P(X | Y) ≠ P(X)
then knowledge of Y gives us some information about X.

In the Bell inequality set-up we have a slightly more complicated conditional probability - but it can be understood in exactly the same way we'd approach the more simple distribution for X and Y above.

So, for example, in the Bell case we might want to examine a conditional probability distribution
P(A | a, b)
and this means something like the "probability that the result A is some value given that the settings of the measuring instruments are a and b". It's certainly one that we can measure from actually performing the experiment.

So here we're assuming that there is some functional dependence on a and b. In a loose sense we might then say that the outcome at A 'knows' that the settings are a and b. More technically we might make the statement that knowledge of the settings at a and b gives us additional information about the probabilities of A.

If there were no such functional dependence on b, say, then we would write
P(A | a, b) = P(A | a)
This latter identification is, of course, a critical component of the Bell proof - it's the imposition of the locality condition. It's an assumption that says that the probability of the outcomes at A is not conditioned upon the settings at b. Expressed another way, we could say that knowledge of the settings at b confers no additional information pertinent to the results at A.

With this locality condition and the assumption of CFD then we can show that the probability functions we measure are constrained by the Bell inequality.

If we don't want them to be so constrained (i.e. have the possibility to violate the inequality) then at least one of these assumptions has to go. If we choose to retain CFD then we have to lose locality, if we want to have the possibility to break those constraints.

 

[Eye_in_the_Sky]

Difficulty is related to independence of spacetime events. I mean that standard philosophical basis takes spacetime events as fundamental to reality and they are arranged in some system (spacetime) that does not allow arbitrary connections between them. And scientific method is developed on top of that standard philosophical basis.

As I see nonseparability is in conflict with the idea of spacetime events as fundamental.

Well, at the core of the "scientific method", I think, is the idea of 'cause' and 'effect'.

On top of that are the constructs of 'space' and 'time', and within that framework the various 'cause' and 'effect' relationships are to be organized.

Now ... what does it mean to say "spacetime events are fundamental"? Does it mean
this?

Given all of the 'effects' in spacetime, the joint-state of all of their 'causes' is 'separable'.
(This joint-state can be regarded as a description of a 'system' that 'resides' within spacetime.)

 

[Eye_in_the_Sky]

... then we are forced to say

The 'quantum state' is PHYSICAL.

That depends on your interpretation of QM. You're certainly not forced to say that.

That is VERY interpretation dependent.

Ok ... Ok. I will have to recast my claim.

______

IF

there is no violation of 'causal locality'

AND

the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B

THEN:

If the "correlation phenomenon" is an 'effect' in spacetime, then there is a 'nonlocal beable' that acts within spacetime as its 'cause'.

... Can we agree on that?
______

beable: that which can bring about an 'effect' in spacetime
______
______

What is the explanation for the non classical correlations that violate Bell inequalities that do not include any superluminal signaling in any aspect of experiment ?

According to what I have claimed above, the answer to your question would be:

If you wish to construe the "non classical correlations" as an 'effect' in spacetime, then the 'cause' of them is a 'nonlocal beable'; it 'acts' within spacetime, but does not itself 'reside' within spacetime.

 

[Eye_in_the_Sky]

*There are classical phemonena with no explanation as well.

Zafa, please give some examples if you can. I can't get clear what you mean.

 

[RUTA]

______

IF

there is no violation of 'causal locality'

AND

the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B

THEN:

If the "correlation phenomenon" is an 'effect' in spacetime, then there is a 'nonlocal beable' that acts within spacetime as its 'cause'.

... Can we agree on that?
______

beable: that which can bring about an 'effect' in spacetime
______
______

The existence of a beable is not necessary. Bohr, Ulfbeck and Mottelson's genuine fortuitousness claims the events are uncaused. Here is a quote from them lifted from http://arxiv.org/pdf/quant-ph/0202148.pdf:

the individual fortuitous event, which quantum mechanics deals with, comes by itself, without any cause, and is entirely beyond theoretical analysis.

 

[bhobba]

If the "correlation phenomenon" is an 'effect' in spacetime, then there is a 'nonlocal beable' that acts within spacetime as its 'cause'.

The correlation is simply the result of how you set things and usually a consequence of conservation laws.

Now via Noethers theorem there is a deep connection between conservation laws and space-time symmetries but that is whole new story.

There is nothing non local about it unless you insist on properties regardless of observation. The nature of the non locality is very interpretation dependent. BM is the best known one - but there are others:
http://arxiv.org/pdf/quant-ph/9508021.pdf

Thanks
Bill

 

[morrobay]

Would the correlations of entangled photons described above
produce outcomes sufficient to violate an Aspect type Bell inequality experiment ?
A(aλ) = ± 1
B(bλ) = ± 1
S ≤ 2
S = E(a,b) + E(a,b') + E(a'b) - E(a'b')

 

[zonde]

Would the correlations of entangled photons described above
produce outcomes sufficient to violate an Aspect type Bell inequality experiment ?

If you consider only measurements that produce perfect correlations you can't get Bell inequality violations.

 

[zonde]

There is nothing non local about it unless you insist on properties regardless of observation.

This is upside down. If you do not consider common past as possible explanation for correlations then you have to invoke non-locality as an explanation.

 

[stevendaryl]

You can have locality and realism (CFD) with retrocausality. Of course the CFD is irrelevant given the outcomes and settings are part of the ontological explanation.

I would say that with retrocausality, you can have realism without CFD. CFD implies that there is a meaningful answer to the question: What result would I have obtained, if I had chosen to measure something else? But in a retrocausal model, I wouldn't think that such questions would be meaningful, in general.

 

[RUTA]

I would say that with retrocausality, you can have realism without CFD. CFD implies that there is a meaningful answer to the question: What result would I have obtained, if I had chosen to measure something else? But in a retrocausal model, I wouldn't think that such questions would be meaningful, in general.

Exactly, that's what I meant when I said CFD is "irrelevant" in retrocausality. It turns out many of the problems facing dynamical explanation per the Newtonian Schema in the mechanical universe are irrelevant when using adynamical explanation per the Lagrangian Schema in the block universe. That was the leitmotif of my Insights series https://www.physicsforums.com/insig...ions-part-1-time-dilation-length-contraction/ . I'm very glad to see someone is understanding the 4D perspective You may not like it, but if you at least understand it, you can appreciate its explanatory power.

 

[Eye_in_the_Sky]

If the "correlation phenomenon" is an 'effect' in spacetime, then there is a 'nonlocal beable' that acts within spacetime as its 'cause'.

... Can we agree on that?
______

beable: that which can bring about an 'effect' in spacetime

The existence of a beable is not necessary. Bohr, Ulfbeck and Mottelson's genuine fortuitousness claims the events are uncaused.

I have asked you whether or not you agree with the "If/then"-statement, and, instead of answering YES or NO, you have answered me that the "If"-part is not necessarily true.

So, I will ask again:

IF

there is no violation of 'causal locality' ,

and

the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B ,

and

the "correlation phenomenon" is an 'effect' in spacetime ;

THEN

There is a 'nonlocal beable' that acts within spacetime as its 'cause'.

... Can we agree on that?
______

beable: that which can bring about an 'effect' in spacetime

 

[Eye_in_the_Sky]

The correlation is simply the result of how you set things and usually a consequence of conservation laws.

Bhobba, from these words of yours it is unclear whether or not you are saying the "correlation phenomenon" is CAUSED or UNCAUSED.

... Which INTERPRETATION are you espousing?

 

[Zafa Pi]

Zafa, please give some examples if you can. I can't get clear what you mean.

Why is the speed of light the value we've measured it to be?
Why do masses attract?, or in GR terms, why does mass affect the geometry of space in the first place?

 

[RUTA]

I have asked you whether or not you agree with the "If/then"-statement, and, instead of answering YES or NO, you have answered me that the "If"-part is not necessarily true.

So, I will ask again:

IF

there is no violation of 'causal locality' ,

and

the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B ,

and

the "correlation phenomenon" is an 'effect' in spacetime ;

THEN

There is a 'nonlocal beable' that acts within spacetime as its 'cause'.

... Can we agree on that?
______

beable: that which can bring about an 'effect' in spacetime

My answer stands.

 

[Zafa Pi]

I have asked you whether or not you agree with the "If/then"-statement, and, instead of answering YES or NO, you have answered me that the "If"-part is not necessarily true.

So, I will ask again:

IF

there is no violation of 'causal locality' ,

and

the states of their instruments bear a relation of 'separability' throughout the spacetime regions A and B ,

and

the "correlation phenomenon" is an 'effect' in spacetime ;

THEN

There is a 'nonlocal beable' that acts within spacetime as its 'cause'.

... Can we agree on that?
______

beable: that which can bring about an 'effect' in spacetime

Is it true that: If 1 + 1 = 3, then I'm the Pope? The answer is yes, but a better answer is RUTA's, i.e. the If is false.
See: http://cds.cern.ch/record/980036/files/197508125.pdf

 

[bhobba]

Bhobba, from these words of yours it is unclear whether or not you are saying the "correlation phenomenon" is CAUSED or UNCAUSED.

They are correlated because they involve bell states. Cause is not the usual word for initial conditions.

I am not espousing any interpretation. I am simply asking you to delve into the detail of Bells theorem. Its all there.

Thanks
Bill

 

[bhobba]

This is upside down. If you do not consider common past as possible explanation for correlations then you have to invoke non-locality as an explanation.

They are correlated because they are bell states. How the bell states are created is an experimental matter - but usually involves some kind of conservation law.

Common past - beats me what you even mean.

Thanks
Bill

 

[Eye_in_the_Sky]

Is it true that: If 1 + 1 = 3, then I'm the Pope? The answer is yes, ...

Oh, come on, Zafa Pi. The "If" of your statement is demonstrably false. But to say:

the "correlation phenomenon" has a 'cause'

– is that demonstrably false?

I think not.

As far as I can tell, the contention that the "phenomenon" is 'caused' belongs the realm of 'possibility'. So, all I am doing is raising the question:

What does that 'possibility', if true, entail?

 

[RUTA]

Oh, come on, Zafa Pi. The "If" of your statement is demonstrably false. But to say:

the "correlation phenomenon" has a 'cause'

– is that demonstrably false?

I think not.

As far as I can tell, the contention that the "phenomenon" is 'caused' belongs the realm of 'possibility'. So, all I am doing is raising the question:

What does that 'possibility', if true, entail?

Turning on the source "causes" the correlated detector outcomes. However, that does not entail the existence of a beable. That was my point.

 

[morrobay]

Oh, come on, Zafa Pi. The "If" of your statement is demonstrably false. But to say:

the "correlation phenomenon" has a 'cause'

– is that demonstrably false?

I think not.

As far as I can tell, the contention that the "phenomenon" is 'caused' belongs the realm of 'possibility'. So, all I am doing is raising the question:

What does that 'possibility', if true, entail?

As bhobba said in # 127 " The correlation is ... usually a consequence of conservation laws "

http://arxiv.org/pdf/quant-ph/0407041.pdf

 

[morrobay]

If you consider only measurements that produce perfect correlations you can't get Bell inequality violations.

https://www.physicsforums.com/threads/murray-gell-mann-on-entanglement.884743/page-5
See post #87. My understanding of perfect correlations is that they only apply when detectors A and B are aligned,
I see no reference on this in post #87.
Also it is stated that A only considers the 50% of photons that are polarized in Φ direction.
My question would apply to all photons detected.

* I would have replied earlier but for unknown reason you and two others were incorrectly put on ignore list.
:

 

[zonde]

See post #87. My understanding of perfect correlations is that they only apply when detectors A and B are aligned,
I see no reference on this in post #87.

This sentence:
"As it turns out, if you consider only those B photons for which A found polarization in direction $|\phi \rangle$, then B will always find polarization in direction $\phi+\pi/2$."
Polarizers at relative angle $\pi/2$ will give perfect correlations.

Also it is stated that A only considers the 50% of photons that are polarized in Φ direction.
My question would apply to all photons detected.

If light is unpolarized then 50% of photons will pass polarizer at any angle. If you want to consider all photons you have to use polarization beam splitter (PBS). It has two outputs: one where you get H-polarized photons and the other one where you get V-polarized photons.

I am not sure I understand your question. Do you ask if we can violate Bell inqeuality with polarization entangled photons? If this is the question then the answer is certainly yes as most of the Bell test experiments are using these.

 

[morrobay]

Am aware that entangled photons violate the inequality. It is the correlations/outcomes without superluminal signaling - explanation
I am interested in. As vanhees71 is describing in post 87.
If you or anyone else can reference another post by vanhees71 in that topic that makes a better example of this I would like to see it.

 

[zonde]

It is the correlations/outcomes without superluminal signaling - explanation I am interested in.
As vanhees71 is describing in post 87. If you or anyone else can reference another post by vanhees71 in that topic that makes a better example. of this I would like to see it.

Ok, then I am not the right person to answer your question. I can only provide arguments why general explanations without superluminal signaling can't work.
Maybe @vanhees71 himself can help you?

 

[Eye_in_the_Sky]

As bhobba said in # 127 " The correlation is ... usually a consequence of conservation laws "

http://arxiv.org/pdf/quant-ph/0407041.pdf

Let's see, here. We are putting these two in juxtaposition:

"the correlation" | "conservation laws" .

On top of that, we are saying that the 'phenomenon' (to the left) and the 'principles' (to the right) bear some kind of a relationship. At the very least, we can say they have a 'logical' relationship of 'implication':

conservation laws → the correlation .

But beyond this, it does not seem correct to me to say that the two can bear a relationship of 'causation'.

Besides, here we are asking about matters of 'causation' between entities (like the instruments of Alice and Bob, or the instrument of preparation) that 'act' in spacetime.

 

[morrobay]

http://arxiv.org/pdf/quant-ph/0407041.pdf

Did you read the paper ? In particular page 4 and 5. If so then what exactly are you questioning ?

 

[Eye_in_the_Sky]

I am not espousing any interpretation. I am simply asking you to delve into the detail of Bells theorem. Its all there.

Ok. I will try.

 

[Eye_in_the_Sky]

If you do not consider common past as possible explanation for correlations then you have to invoke non-locality as an explanation.

Common past - beats me what you even mean.

Zonde means the overlap of the backward light-cones of the spacetime regions A and B.