Non-locality

[Dalo]

 

I would like to point out that my analysis also holds in the case of the famous Aspect experiment of 1982. After all, two fundamental conditions are fulfilled.

1) Both photons are identical,

2) both photons undergo measurements by identical devices.

Edited December 17, 2017 by Dalo

[studiot]

4 hours ago, Dalo said:

I am not sure what it is supposed to mean. I know the drawing, forgot its name, looks likes Escher's drawings. I have read some Penrose, but certainly not enough to pretend to know his ideas. What I remember of him is his attempt to link consciousness with quantum theory. Not very convincing.

 

So are you stating categorically that Penrose is incorrect to display that drawing as non local?

Or are you disputing my statement that there are many ordinary common or garden examples of non locality in ordinary common or garden classical mechanics?

Perhaps you should confirm in a few words exactly what you think non locality means.

Any other discussion (including slagging him off) of Penrose is OFF TOPIC.

Edited December 17, 2017 by studiot

[Dalo]

8 hours ago, studiot said:

 

So are you stating categorically that Penrose is incorrect to display that drawing as non local?

Or are you disputing my statement that there are many ordinary common or garden examples of non locality in ordinary common or garden classical mechanics?

Perhaps you should confirm in a few words exactly what you think non locality means.

Any other discussion (including slagging him off) of Penrose is OFF TOPIC.

I said I have no idea what the drawing is supposed to mean. You should make it clear, you brought it in.

8 hours ago, studiot said:

Or are you disputing my statement that there are many ordinary common or garden examples of non locality in ordinary common or garden classical mechanics?

Perhaps you should confirm in a few words exactly what you think non locality means.

Perhaps you should confirm in a few words exactly what you think non locality means.

**************************************************

"Definition
the returns of the disposition of any ray to be reflected I will call its fits of easy reflection, and those of its disposition to be transmitted its fits of easy transmission..." [see also Proposition XVII ff] Isaac Newton (Second Book of) Opticks.

Just like with polarization, we can determine empirically the percentage of light reflected or transmitted through glass of variable thickness, but like Feynman confirmed, we have no explanation for the phenomena. 
We can then search for the explanation of this very local phenomena in a mysterious entanglement or in non-local hidden variables. I am convinced that we would be then looking in the wrong place.
The mystery lies in the interaction of light with glass or polarizing filters.

I have asked about the fact that the first polarizer absorbs or reflects 50% of the beam because it seems mysterious to me when compared to the percentages created by the second filter.

We have no idea why the percentages are what they are. In fact, Feynman uses our ignorance not to encourage us to look for a solution, but to convince us of abandoning the search: Nature is just what it is, probabilistic, and there is no reason to search for something else besides probabilistic regularities..

This is turning your ignorance in a metaphysical property of reality, thereby justifying this ignorance.

Edited December 17, 2017 by Dalo

[studiot]

47 minutes ago, Dalo said:

I said I have no idea what the drawing is supposed to mean. You should make it clear, you brought it in.

 

 

Why should it mean anything?

It was stated to be real world example of non locality.

What does a football mean?

It is also a real world example of a different form of non locality.

 

47 minutes ago, Dalo said:

Perhaps you should confirm in a few words exactly what you think non locality means.

**************************************************

 

"Definition
the returns of the disposition of any ray to be reflected I will call its fits of easy reflection, and those of its disposition to be transmitted its fits of easy transmission..." [see also Proposition XVII ff] Isaac Newton (Second Book of) Opticks.

Just like with polarization, we can determine empirically the percentage of light reflected or transmitted, but like Feynmann confirmed, we have no explanation for the phenomena. 
We can then search for the explanation of this very local phenomena in a mysterious entanglement or in non-local hidden variables. I am convinced that we would be then looking in the wrong place.
The mystery lies in the interaction of light with glass or polarizing filters.

 

This jumble of words clearly demonstrates to me that you have no idea of the meaning of non locality or of the many and varied examples of its manifestation that occur in the real world.

 

Perhaps unfortunately your eyes have been dazzled (like many other eyes) by the unwarranted mysticisim attached to one alleged form of non locality.

Edited December 17, 2017 by studiot

[Dalo]

Just now, studiot said:

Perhaps unfortunately your eyes have been dazzled (like many other eyes) by the unwarranted mysticisim attached to one alleged form of non locality.

That is of course always possible. But we won't know until you have dazzled us with your knowledge of what non-locality really means.

[studiot]

I'm sorry I can't offer any dazzle factor on what is a very pedestrian and mundane concept.

In many instances it is known by a much more prosaic name, to whit,  'distributed'.

This would be the case of the football.

 

Non locality occurs when a specific locality (ie point in a coordinate system) cannot be allocated to a particular observable (and measurable) phenomenon or effect.

If the effect can't be observed or measured (ie it has no impact on the real world or part of it) then it might as well not exist.

So the pressure within an inflated football has no point of application - it is distributed within and at the surface of the ball.

The figure I displayed is a perspective of an object that would be impossible in normal 3 dimensions.

Yet it is also impossible to allocate any single point on that drawing that is 'impossible'. Any part of that drawing could be part of a real 3D object.
It is only in totality or completeness that it is impossible

This brings us to an interesting feature of such non local properties.

That it may result in an emergent phenomenon.

The humble arch is a less flambouyant example.
The extreme structural property of the arch only emerges when the entire arch is in place.
It does not reside in any part of the arch exclusively.
Not only this but the emergent strength acts in a direction perpendicular to any other strength the arch may possess.

A distributed load on a beam is non local, as is atmospheric pressure - they act everywhere.

I tried to tell you in another thread that any wave is a non local phenomenon,  but you wouldn't listen.

Edited December 18, 2017 by studiot

[Dalo]

5 minutes ago, studiot said:

A distributed load on a beam is non local, as is atmospheric pressure - they act everywhere.

I tried to tell you in another thread that any wave is a non local phenomenon,  but you wouldn't listen.

Well, I must say that your definition of non-local is very clear. I just wonder whether it can be applied to the discussion at hand. Because, if you are right the whole debate between Bohr and Einstein, and its follow up even up to the 21st  century is a waste of time. Einstein and his friends (EPR, Schrödinger) had apparently no idea of the meaning of non-locality.

Congratulations, your solution is even simpler than mine: non-locality is a non-problem.

[swansont]

15 hours ago, Dalo said:

 I must admit that I am facing the same wonderment, and I have read and re-read the arguments presented by Maudlin, convinced that I had overlooked some simple fact that would make me look like a fool.

There is nothing difficult in what I say: both photons show the same behavior and the same statistical regularities for the simple reason that they are identical to each other, and so are the polarizing filters. The distinction between local and non-local is therefore meaningless!

But if it were that simple, why hasn't anyone come up with the idea then?

Here's the problem: it's not enough to have the photons be identical. You can prepare a sample of identical photons and subject them to the same conditions, and you will not get the same behavior. Prepare them in a polarized state and send them into a polarizing beam splitter at 45 degrees. You will only get the correlated polarization half the time. Pick a different angle, and the amount changes, but it won't match the entangled result.

[studiot]

There is a further twist to this story, that applies to relativity.

There can be degrees of non locality.

The (measurable)  property of curvature can be local or non local.

However another word is often (wrongly) taken to mean non local and that is global.

You can measure the curvature of a curve at any point (locally).

For example the curvature of a right circular helix is the same throughout its length so its curvature is global.

Measure it at one point and you have determined the curvature at every point

However the curvature ofan irregular curve that meanders its way through space cannot be so determined. Knowing the curvature at one point does not help know it somewhere else.

So this is no longer a global property.

This is, of course, the situation in a universe with randomly distributed matter, und General Relativity.

 

[swansont]

16 hours ago, Dalo said:

 In Maudlin's book, the part about polarization, he mentions the fact that any filter, whatever its direction, absorbs half of the photons and let the other half pass. I have come across this rule many times, but I could never make sense of it. Could you explain it in easy words, or have you maybe a link I could look up?

I'm quite sure the author says more than that, as context for this statement, because it is not true otherwise. If you have polarized light, you can pass none of it, or all of it, or any fraction in between.

The statement is true if the light is unpolarized, or if the light is polarized and the angle of the polarizer is at 45º. In both cases you can view the light as being comprised of half of one polarization and half of the perpendicular polarization, and the polarizer blocks the half that it's supposed to block. 

[Dalo]

17 minutes ago, swansont said:

The statement is true if the light is unpolarized

That is exactly the point which I do not understand. Light, once polarized, can have any direction. before it is polarized it has all possible directions, so why would a polarizer absorb or transmit 50% and not a percentage equivalent to the direction of the polarizer?

************************************

19 minutes ago, studiot said:

There is a further twist to this story, that applies to relativity.

I do not doubt the validity of what you are saying, only its relevance to the subject of the thread. Non-locality in QT is not what you are describing.

****************************************

21 minutes ago, swansont said:

Here's the problem: it's not enough to have the photons be identical. You can prepare a sample of identical photons and subject them to the same conditions, and you will not get the same behavior. Prepare them in a polarized state and send them into a polarizing beam splitter at 45 degrees. You will only get the correlated polarization half the time. Pick a different angle, and the amount changes, but it won't match the entangled result.

I would honestly not be surprised at all if somebody knocked off my argumentation. After all we are talking about the greatest minds in Physics, and there would be no shame for me if it turns out that I have overlooked some essential elements, and been misled to the wrong conclusion.

But I do not understand your objection, because that is exactly what Maudlin pretends. He states explicitly that both photons show the same polarization. I do not know of other properties, but they do not seem to be relevant to the experiment. It is all about the direction of polarization.

 

4 minutes ago, Dalo said:

You will only get the correlated polarization half the time. Pick a different angle, and the amount changes, but it won't match the entangled result.

That is also a fundamental point of the issue: the statistical regularities.

I have never assumed a deterministic correlation: 100% passed or absorbed, or any other invariable percentage..

22 hours ago, Dalo said:

I do not question the statistical regularities in quantum theory.

 

Edited December 18, 2017 by Dalo

[Mordred]

Some interesting discussion going on now. Particularity Studiot who demonstrated that local can have numerous definitions. Well done.

Here is another as applied to Cosmology which is completely different than QFT or QM.

Local is an anistrophy deviation from the global homogeneous and isotropic distribution. Which can be further described as a seperate causality system. Examples include large scale structure formation. Stars, planets, galaxies. The temperature deviations of the CMB.

Certainly stresses the point of understanding in what context (system) the terms local and non local are being applied to

Edited December 18, 2017 by Mordred

[Dalo]

Just now, Mordred said:

which is completely different than QFT or QM

You won't mind then if I do not go into all those different kinds of non-locality, of which by the way I have no understanding.

[Mordred]

That would have to depend on how your describing the terms in accordance to which type of treatment or system your defining the terms under.

If your sticking to QM/QFT then include those points and avoid any cover all blanket statements.

I would certainly hope you picked up on one essential detail however on those two terms that is common to all definitions. (as applied in metaphysics)

Edited December 18, 2017 by Mordred

[Dalo]

Just now, Mordred said:

If your sticking to QM/QFT then include those points and avoid any cover all blanket statements

That sounds like a good advice, but didn't I do that implicitly in the description of the problem I was studying and the claim I was presenting?

[Mordred]

Well that in itself is a little grey when you stepped into your metaphysics arguments.

There is one blanket cover all statement that can be accurately applied to the term local. I'm hoping you will see it.

[Dalo]

Just now, Mordred said:

Well that in itself is a little grey when you stepped into your metaphysics arguments.

There is one blanket cover all statement that can be accurately applied to the term local. I'm hoping you will see it.

I am afraid I don't.

[Mordred]

How about sonething along the lines of.

The term local is itself an abstract device whose definition will depend upon the system being described, it in itself does not define a fundamental reality as its usage depends upon how the term is applied.

[Dalo]

13 minutes ago, Mordred said:

How about sonething along the lines of.

The term local is itself an abstract device whose definition will depend upon the system being described, it in itself does not define a fundamental reality as its usage depends upon how the term is applied.

Again you are right. But non-local in the context of the debate Bohr-Einstein, and also in the context of Maudlin's article which you have shared, is unambiguous. There could be no misunderstanding about which sense of non-local was used. And neither you nor Swansont misunderstood the meaning.

There are many words, not all of them technical terms, that have multiple meanings (polysemy) and which only get a precise meaning not by explicit declarations but by the context  of their use. I am not responsible for the associations created by those words. The context should always come first. I do not think there could be any ambiguity concerning the context of my thread.

edit: nowhere in the literature about (non)-locality in QT did I encounter the other meanings of this expression. Not a single author I know of felt the need to expand on the different meanings of (non-)locality, and how different it is from (non-)locality in RT or cosmology.

Edited December 18, 2017 by Dalo

[Mordred]

When applied to a particular system I agree, however one should always be aware that what applies in one context may not be applied in another. Particularly when you make a metaphysical statement which should include all possibilities ( though I rarely see any that truly do)

Lol remember I did stress the importance of cross examinations lol always stay objective. Never set your mind in stone on a given topic.

I once mentioned this on another forum to a Ph.D in QFT when I questioned his usage of the term Real. He wasn't particularly receptive.

Edited December 18, 2017 by Mordred

[Dalo]

                                                                                 THERE'S NO FIRE HERE! NO FIRE!

http://residentevil.wikia.com/wiki/Anna_Bolt?file=Anna_yells_at_the_Red_Queen.jpg

 

 

Edited December 18, 2017 by Dalo

[Dalo]

Apparently nobody knows why the first polarizing filter absorbs or transmit 50% of the beam.

It makes you wonder how quantum scientists dare draw any conclusion regarding the behavior of a second photon (identical to the first) and a second filter (identical to the first).

I mean, they are not even able to give a complete account of the initial conditions!

By the way, I don't mean a "metaphysical why", but a plain common "physical why" that would explain why light (be it a wave and/or a particle) reacts this way to a first polarizer, just to change completely its front door policy right after.

But maybe I am too impatient, and I should just wait for somebody to explain to me the nuts and bolts of this physical phenomenon.

Edited December 18, 2017 by Dalo

[Klaynos]

43 minutes ago, Dalo said:

Apparently nobody knows why the first polarizing filter absorbs or transmit 50% of the beam.

 

This is why the discussions you start don't seem to go anywhere. 

As a prerequisite to a discussion on entanglement is a knowledge of polarisation. You don't have that knowledge so don't know the bits of information you're missing when reading about the details. 

Polarisation isn't just the linear orientation of fields. It's more complicated than that. No one wants to spend the time teaching you the basics when you're wandered in out of your depth insisting you're correct. Sorry to be blunt but that's the way it is. 

[Dalo]

5 minutes ago, Klaynos said:

when you're wandered in out of your depth insisting you're correc

I may have wandered in out of my depth, but I kept repeating that I would certainly not be surprised if somebody proved me wrong.

I have faithfully presented Maudlin's example and arguments and I know enough about polarization to know that not a single author has ever explained why the first filter absorbs or transmits 50% of the beam, while the second filter does that according to the angle of misalignment.

Maybe you know the answer that I could not find anywhere, and that neither Swansont nor Mordred have given until now. If you do not either, then climb off your high horse please.

If you do know and are willing to share it I will be eternally grateful and will apologize deeply and profusely.

Edited December 18, 2017 by Dalo

[swansont]

9 hours ago, Dalo said:

That is exactly the point which I do not understand. Light, once polarized, can have any direction. before it is polarized it has all possible directions, so why would a polarizer absorb or transmit 50% and not a percentage equivalent to the direction of the polarizer?

Any given polarization direction has some probability of transmission given by Malus's law. It's just like half of the beams being vertical, and half being horizontal. So half get transmitted, and half absorbed.

9 hours ago, Dalo said:

 I would honestly not be surprised at all if somebody knocked off my argumentation. After all we are talking about the greatest minds in Physics, and there would be no shame for me if it turns out that I have overlooked some essential elements, and been misled to the wrong conclusion.

But I do not understand your objection, because that is exactly what Maudlin pretends. He states explicitly that both photons show the same polarization. I do not know of other properties, but they do not seem to be relevant to the experiment. It is all about the direction of polarization.

No, it's not. It's about entangled states.

 

 

2 hours ago, Dalo said:

Apparently nobody knows why the first polarizing filter absorbs or transmit 50% of the beam.

It was explained to you, but the fact that you don't understand doesn't mean nobody else does.

2 hours ago, Dalo said:

It makes you wonder how quantum scientists dare draw any conclusion regarding the behavior of a second photon (identical to the first) and a second filter (identical to the first).

Because they understand the physics involved.

2 hours ago, Dalo said:

I mean, they are not even able to give a complete account of the initial conditions!

Not being able to give that account is a crucial part of entanglement. Again, the people doing the physics understand the physics. 

 

1 hour ago, Dalo said:

I may have wandered in out of my depth, but I kept repeating that I would certainly not be surprised if somebody proved me wrong.

I have faithfully presented Maudlin's example and arguments and I know enough about polarization to know that not a single author has ever explained why the first filter absorbs or transmits 50% of the beam, while the second filter does that according to the angle of misalignment.

Maybe you know the answer that I could not find anywhere, and that neither Swansont nor Mordred have given until now. If you do not either, then climb off your high horse please.

If you do know and are willing to share it I will be eternally grateful and will apologize deeply and profusely.

The authors of an advanced text probably assume you understand any prerequisite material; they are not going to reinvent the wheel. Similarly, when you show up wishing to discuss and advanced topic like non-locality, there is the expectation that you understand some basic physics.

Sadly, that doesn't always happen, and we get the same, predictable behavior that we see here. (This is nowhere near the first time for this)

If you have deficiencies in your background (and you obviously do), you need to remedy that. Nothing is keeping you from starting a thread to ask about polarization. If you persist with more advanced topics, you are going to be wrong, and post nonsense. That, coupled with showing an attitude when people correct your mistakes, is an untenable situation.