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Offline sciconoclast

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Is remote entanglement not proven ?
« on: 31/03/2011 17:03:04 »
" not proven " is of course the general term applied to a concept that is possible but for which there is an absence of observational proof.  This is an inquiry as to the present state of a main stream topic.

All of the proof I have seen involves violation of the Bell Inequality.   Bell assumed that there would be an inequality in the ratio between possible parameters of non-entangled electrons or photons.   However, experimentally the non-entangled photons violate the Bell inequality at the same ratio as entangled photons.

I am including a reference because this fact is often under reported: http://www.upscale.utoronto.ca/PVB/Harrison/BellsTheorem/BellsTheorem.html 

"The difference is that a collection of, say, a billion electrons from the source in the correlation experiments always behaves identically within small and expected statistical fluctuations with every other collection of a billion electrons from the source."

Another assumption made by Bell was that a photon cannot change its polarization to pass through a polarization detector.   The Freedman and Clauser experiment disproved this assumption.  Again; I feel compelled to present a reference:  http://en.wikipedia.org/wiki/Bell%27s_theorem   

"In the total set of signals from an atomic cascade there is a subset whose detection probability increases as a result of passing through a linear polarizer.....Moreover, the analysis leads us to recognize that the Bell-inequality experiments, rather than showing a breakdown of realism or locality, are capable of revealing important new phenomena......The quantum mechanical wavefunction can also provide a realistic description, if the wavefunction values are interpreted as the fundamental quantities that describe reality."

Remote entanglement is an extreme concept, is there any experimental varification?   

Edit: I am modifying this original post to add the more technical quotes and references that I placed in my last post in response to your_on's request along with an apology for not incorporating them originally.

"We demonstrate a novel approach of violating position dependent Bell inequalities by photons emitted via independent sources in free space." from the paper: Creating Entanglement and Violating Bell Inequalities by independent photon sources.     arxiv.org/pdf/1001.3830

"We calculate the amount of polarization-entanglement induced by two photon interference at a lossless beam splitter." from the paper:   Entanglement ability of a beam splitter in the presence of temporal which-path information.       arxiv.org/pdf/quant-ph/0503204

In ieexplore the paper:   Heralded twp-photon entanglement from probabilistic quantum logic operations on multiple parametric down-conversion sources. 
« Last Edit: 12/04/2011 17:29:28 by sciconoclast »


 

Offline Ron Hughes

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Re: Is remote entanglement not proven ?
« Reply #1 on: 31/03/2011 17:54:01 »
If there is a reality separate from observation then QM fails and entanglement fails.
 

Offline yor_on

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Re: Is remote entanglement not proven ?
« Reply #2 on: 31/03/2011 18:18:44 »
Hm?

First of all a photons spin is in fact 'everywhere' as I understands it. It's the measurement that defines it to some 'direction'. The idea of 'entanglements' as such comes from the Einstein–Podolsky–Rosen paradox (EPR) in where they questioned the idea of HUP (Heisenberg Uncertainty Principle) and that there was no way to define all parameters of a particle simultaneously.

They reasoned that if you made a measurement on one of two particles, split out from one original, 'action and reaction' would guarantee that both particles flow in a equally opposite direction if 'split' in the exact 'middle' and that any measurement done on one of the particles also would define the other as they were each other 'mirrors', just traveling in the opposite directions. And combining the knowledge of the particle they measured with the knowledge they have about 'action and reaction' there could be no question of that they if measuring the position of the right one also would know the position of the left and if measuring the right particles speed you would also know the left. In that manner they described a situation where you by measuring one of the particles actually would know all there was to know about the one not measured. And this goes back to the question if the ' moon exist when you do not look' in fact. Einstein withheld that the moon would be there no matter if you looked or not, QM is not as sure :)

What Bell did was to wonder if there was some way to decide which theory of 'reality' was right. He realized that if you assumed three measurements of, for example the axis of the particles 'spin', you would be able to logically prove if it was true or not. The question of if those 'identical' particles could be finally defined by a measurement or not. And the way was statistical, by doing a lot of measurements (on the right side particles) you would see if there was a absolute correlation between the right and the left particle as EPR assumed. If there was, the statistics had to show a correlation of more than a 50 percent of the cases to make EPR true, meaning that measuring of a arbitrarily chosen spin (polarizations) direction of some axis, randomly chosen each time, would need to be a absolute correlation in, over 50 % of the cases observed, for existing a way to question HUP and indeterminacy. The experiments was done and found to be under the threshold statistically, and so the moon became 'questionable'. Aspects experiments was the final nail in the coffin for the idea of everything 'existing' as measurable parameters, as I understands it.

"The most recent experiment by Aspect, Dalibard, and Roger, used acousto-optical switches at a frequency of 50MHz which shifted the settings of the polarizers during the flight of the photons, to completely eliminate any possibility of local effects of one detector on the other. Nevertheless, they reported that the EPR assumption was violated by five standard deviations, whereas quantum theory was verified within experimental error (about 2%). "

But it's a hard subject to stomach this one.
 

Offline yor_on

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Re: Is remote entanglement not proven ?
« Reply #3 on: 31/03/2011 18:39:20 »
There are several ways to see the confusion here. One is to keep defining 'reality' from how we see it naievly and intuitively. It's very human to do so :) and it makes sense to do it too as we all like some sort of stability in our reality. Or you can start to question the idea of 'locality'. Locality is just another name of 'distance' and there are so many indications of it being different than what we assume now, both from a QM perspective as well as from the idea of 'SpaceTime'. The question is not one about 'locality' versus 'non-locality' as I see it. The question is about if we describe 'motion'  and 'distance' the same way the universe describes it. And there I think the evidence speaks for themselves. We fail.
 

Offline sciconoclast

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Re: Is remote entanglement not proven ?
« Reply #4 on: 04/04/2011 02:38:17 »
I appreciate your intent to help; but, really, you are all over the place with this one.

Bell calculated different probabilities for two different spin states appearing; one if classical theory was correct and one if remote entanglement was correct.   Your value of 50 per cent is correct for the remote entanglement hypothesis ( if the two alignments tested for have a 45 deg. angle between them ), which is what was found in the Bell Experiments for entangled photons or electrons.   However, what brings the Bell Theorem and the results into question is that the same 50 per cent ratio was found for non-entangled photons or electrons which is not predicted for either theoretical model.

The idea of entanglement does not come from the Einstein-Podoisky-Rosen Paradox nor was E.P.R. supposed to challenge the uncertainty principle as you stated.  Instead the E.P.R. experiments where designed to challenge Bohr's concept of non-locality.   If two correlated photons were tested for the same alignment simultaneously and found to have opposite values, then non-locality was false because the information from one tested photon could not be conveyed instantaneously to the other photon according to the principles of relativity.

When these experiments were performed the particles were found to be entangled at close to 100 percent.   At first this was thought to discredit Bohr but then he introduced the concepts of remote entanglement and instantaneous quantum field collapse.   Bell came up with what he theorized was a method to test the to ideas.

The exception to the Heisenberg Uncertainty Principle that came about by testing two separate alignments in two entangled photons to create knowledge about both alignments in both photons was just an interesting by product.  Although Heisenberg and Bohr are both consider members of the same school of thought; unlike Bohr, who considered the quantum field equations as only mathematical abstractions, Heisenberg considered the quantum field equations to be describing a real wave.  If this is actually the case then there would be no need for remote entanglement.

 When the terms of local and non-local reality are used in discussing these experiments it is not a reference to time or distance.  Instead it refers to the mirror image properties coming into existence by the initial source incident or by the testing for them.

The necessity for the quantum field to encounter a test for a photon before the probability field collapses into an actual photon with the accompanying interaction, is a principle of the main school of thought for quantum theory.   The idea that the results must also be observed by a conscious being is part of quantum philosophy and is not physics but, at best, metaphysics.   Never the less experiments where done where things such as paths taken were controlled by both humans and random mechanical devices.  When the results were compared conscious observation was not a factor.

Don't worry about the moon.  Most of the quantum fields for its material collapsed into real ( a relative term ) particles a long time ago.   I will think about it some more while taking a walk through the forest to see if any trees fell when nobody was around to see it.
« Last Edit: 04/04/2011 04:17:54 by sciconoclast »
 

Offline JP

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Re: Is remote entanglement not proven ?
« Reply #5 on: 04/04/2011 03:17:12 »
Of course it's not proven, since science doesn't work by proving things.  There's good evidence for it, since experiments match very well with quantum mechanics, which in turn predicts entanglement, but these experiments don't rule out every alternative explanation (though they do rule out the most obvious explanations), nor are they perfect tests of Bell's inequalities.  If quantum mechanics is correct and entanglement exists, then there have been suggestions that there may never be a perfect test of Bell's inequalities due to the very nature of quantum mechanics.
 

Offline yor_on

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Re: Is remote entanglement not proven ?
« Reply #6 on: 04/04/2011 13:17:25 »
It was the uncertainty principle it attacked. And that's what I meant :)
But you're right, it was locality or non-locality as EPR was constructed to test. Should have thought about what I wrote there. But as far as I'm concerned it's HUP it questions (in the end), the whole idea of nothing being certain. That was the big one for Einstein. All of those experiments was evolved to question the idea of QM:s uncertainty, and the effects coming from that. And yes, I'm all over the table here :) When he constructed it they had as their proposal that you by measuring one side would know all there was about the other, and that was a direct attack on the uncertainty principle as I see it, even though it seems like the opposite here, as we're discussing a entanglement. Check it up.
==

As for what locality/non-locality means?
A temporal and space like 'distance', and if they can be 'connected' outside of the constants that rule us macroscopically. Why I was all over the table? Well you're up too the same sort of questions that I look at too :) That is HUP and entanglements. Those are important, and the question about interpretation(s) is what will define the result(s). As far as I can see it was Einstein–Podolsky–Rosen paradox that laid the foundation for entanglements with the EPR (thought) experiment, even though it was Schrödinger that coined the word. Einstein actually more or less laid the groundwork for much that now is assumed to be purely QM, even though he did from the idea of disproving it at first. Later he seems to have changed his view about that although the moon was a big one for him, and me too :)

Take that walk and see what you learn.
« Last Edit: 04/04/2011 13:35:27 by yor_on »
 

Offline yor_on

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Re: Is remote entanglement not proven ?
« Reply #7 on: 04/04/2011 13:53:25 »
Rereading you.

"However, what brings the Bell Theorem and the results into question is that the same 50 per cent ratio was found for non-entangled photons or electrons which is not predicted for either theoretical model."

A link to what you talk about there please. That's a very weird statement to me, I'm not sure what you mean by it? What you seem to be saying there is in fact that, either all photons and electrons are entangled, or else the statistics and logic Bell used was wrong? And the logic he used can't be wrong, as far as I can see? Not without questioning most of the logic we build our mathematical propositions on. Or else I'm reading that all electrons are entangled (and photons)? That's a new one to me, worthy of a Nobel prize, or ten if proved by that link :)
==

I tried to search on it but I can't seem to find what you mean there?
Do link this one so I can see how you meant.

As long as we define this world as having a causality chain following logic, he makes sense to me. As soon as we step out of that world into one where our sort of logic may be faulty, he becomes questionable. But in that case so will all/most? (one never really knows with those mathematicians:) of our math be, it seems to me? As they are built on our causality, and axioms, e.g one and one is two and what may follow from that.

« Last Edit: 04/04/2011 14:19:36 by yor_on »
 

Offline sciconoclast

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Re: Is remote entanglement not proven ?
« Reply #8 on: 04/04/2011 19:23:01 »
your_on:
         I provided links in the original post.

JP:  thanks!
             Thanks for what appears to be a reasonable and informed answer to my question.
         
 

Offline yor_on

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Re: Is remote entanglement not proven ?
« Reply #9 on: 05/04/2011 00:02:47 »
Which one?

"The Freedman-Clauser experiment (1972) and later tests of the Bell inequality (Clauser and Shimony, 1978; Aspect, 1982a,b) have demonstrated that quantum mechanics (and nature) cannot simultaneously have the properties of CFD and locality."  Try this one for size. They seem to have another opinion about the experiment?

This one explains it very well I think.

" Bell's inequality

Bohm's new version of the EPR paradox didn't in itself offer a way to test these radically different worldviews, but it set the scene for another conceptual breakthrough that did eventually lead to a practical experiment. This breakthrough came in 1964 from a talented Irish physicist, John Bell, who worked at CERN, the European center for high-energy particle research in Switzerland. Colleagues considered Bell to be the only physicist of his generation to rank with the pioneers of quantum mechanics, such as Niels Bohr and Max Born, in the depth of his philosophical understanding of the implications of the theory. What Bell found is that it makes an experimentally observable difference whether the particles described in the EPR experiment have definite properties before measurement, or whether they're entangled in a ghostlike hybrid reality that transcends normal ideas of space and time.

Bell's test hinges on the fact that a particle's spin can be measured independently in three directions, conventionally called x, y, and z, at right angles to one another. If you measure the spin of particle A along the x direction, for example, this measurement also affects the spin of entangled particle B in the x direction, but not in the y and z directions. In the same way, you can measure the spin of B in, say, the y direction without affecting A's spin along x or z. Because of these independent readings, it's possible to build up a picture of the complementary spin states of both particles. Being a statistical effect, lots of measurements are needed in order to reach a definite conclusion. What Bell showed is that measurements of the spin states in the x, y, and z directions on large numbers of real particles could in principle distinguish between the local hidden variable hypothesis championed by the Einstein-Bohm camp and the standard nonlocal interpretation of quantum mechanics.

If Einstein was right and particles really did always have a predetermined spin, then, said Bell, a Bohm-type EPR experiment ought to produce a certain result. If the experiment were carried out on many pairs of particles, the number of pairs of particles in which both are measured to be spin-up, in both the x and y directions ("xy up"), is always less than the combined total of measurements showing xz up and yz up. This statement became known as Bell's inequality. Standard quantum theory, on the other hand, in which entanglement and nonlocality are facts of life, would be upheld if the inequality worked the other way around. The decisive factor is the degree of correlation between the particles, which is significantly higher if quantum mechanics rules."

I don't see how you mean there? As for how one can prove or disprove that the photon doesn't set its opposite spins in the beam splitter? You could argue that as you measure over different axis the opposite twins spin always will have to be of the exact opposite axis (spin polarization) when the first photon is measured. So measuring the other directly after and finding it being the exact opposite should seem a pretty good proof to me, assuming that you measure it setting different axes varying your test. If you see what I mean?
===

"The Freedman-Clauser (FC) experiment employs linear polarizing filters and measures the coincident transmission yield of the two photon detectors when the principal axes.... of the two filters are set at angles thetaA and thetaB ...., which are varied independently..... ( my ... :)

Quantum mechanics predicts that the experimentally observed yield will depend only on the relative angle thetarel = (thetaA - thetaB) between the two principal axes, and further that for ideal filters the yield will have the normalized angular dependence:"
==


As if you do that, and constantly find the entangled twin to have a opposite spin, you should be able to dismiss the notion of a spin being set in the beamsplitter, well, as I see it? It's a question I also been wondering about :) on and off, but if I'm correct in my assumption, that it is this the experiment cited tells us, the answer becomes pretty clear to me?
« Last Edit: 05/04/2011 00:11:58 by yor_on »
 

Offline sciconoclast

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Re: Is remote entanglement not proven ?
« Reply #10 on: 05/04/2011 01:43:53 »
Okay, hello again your_on.

You stated: "So measuring the other directly and finding it being exact opposite should seem pretty good proof", and "As if you do that and constantly find the entangled twin to have an opposite spin,".

In the Bell experiments there is no test for opposite spins in correlated photons as that is already assumed.   What is tested for is the frequency with which one particular spin occurs in one photon and a different particular spin occurs in the other entangled photon.   

That is explained in the text that you copied describing the Bell Theorem. { Opposite values for the same spin are, however tested in the E.P.R. experiments and the value is 100 per cent for both predetermined and remotely entangled models }.   What the portion of the text you entered is lacking is that the same 50 percent ratio applies when uncorrelated photons are tested.   

That is the subject of the first quote taken from the first web site reference in my original post.   This most likely does not mean that all photons are entangled or that Bell's logic is faulty.   Instead, it may means that the models for electrons and photons that his logic was based on is incorrect
 

Offline yor_on

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Re: Is remote entanglement not proven ?
« Reply #11 on: 05/04/2011 02:12:23 »
Try to find a better link for that if you can. It's a new statement to me, and I would really be interested in seeing it proved in a experiment. If anything it should be at arXiv.org I think?

As for the entanglements in the Freedman-Clauser experiment it seem that they arbritarily, not really but still, set their polarizations testing Bells inequality. If you assume that spin is 'everywhere' on that photon, but gets locked by your observation then it fits the experiment as I read it. If you assume that the 'spin' gets locked in the beamsplitter then you have to find a way to explaining how they, depending on how they use their detectors, can get three different spins from it.

You could assume that a spin then is something that you can set several times, but it makes no sense as a photon only describes itself in that final interaction. A beamsplitter, as I understands it, separate a, let's call it a wave here, into two, let's call it photons here. It 'down-converts' the original energy into half, as it 'split' the original into those 'photons'. There are other ways to do it than this, but they all involve down-converting something that to its nature now is in a superposition, and depending on your setup, able to express itself any which way in its final interaction, as photons or as waves.

To assume it to be set in the beam splitter would then mean that it will be able to interact without annihilating. Also that it can do that how many times you like, as long as there is no real interaction. That depends on how you define it though. If you do as me then you got two new 'photons' from one. Doing so and assuming that its spin gets set in the beamsplitter means that there can't be any more 'spins' possible for them, ever. What the detector will see then should be the same no matter how they manipulate their detector. But as we can see them getting different spins in their measuring that shouldn't be possible?

Or you define it as there is a difference between a conscious observation and 'dead matter', as our beamsplitters. And, doing so, assume that it is the interaction with the person monitoring that decides a outcome. But that becomes a magical universe to me. When it gets 'split' the original 'photon/wave' interacts with the beamsplitter, annihilating itself in that it get down-converted into the 'twins'. What one might wonder is if there is a connection between the original photons spin and those two. But trusting in the idea of 'superpositions' that question seems to become meaningless?


« Last Edit: 05/04/2011 06:28:20 by yor_on »
 

Offline sciconoclast

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Re: Is remote entanglement not proven ?
« Reply #12 on: 10/04/2011 19:50:09 »
Here are some links.
       When I said that the same results with non-correlated photons and the role of detection were under reported;   I meant in the popular science magazines.   In the physics journals how non-correlated photons can violate the Bell Inequality ( the indication for entanglement ) is a major topic.   There are hundreds of papers on how and when or if they become entangled as well as how the type and presence of a detection can influence the results.   I admit that the original links were not to very good sites but I used those sites because they used terms anyone could understand.   In answer to your request, here are some sample arxiv links.

"We demonstrate a novel approach of violating position dependent Bell inequalities by photons emitted via independent sources in free space."; from the paper: Creating Path Entanglement and Violating Bell Inequalities by Independent Photon Sources.     arXiv.org/pdf/1001.3830

"We calculate the amount of polarizer-entanglement induced by two photon interference at a lossless beam splitter."; from the paper: Entangling Ability of A Beam Splitter in the Presence of Temporal-Which Path Information.     arxiv.org/pdf/quant-ph/0503204


If you are a member of Ieexplore, here is a paper you may also be interested in:  Heralded Two-Photon Entanglement from Probabilistic Quantum Logic Operations on Multiple Parametric Down-Conversion Sources.

I hope this is helpful. 
 

Offline sciconoclast

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Is remote entanglement not proven ?
« Reply #13 on: 15/04/2011 23:34:06 »
your_on?   What, no comments?    No thanks for the links to the information?
 

Offline yor_on

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Is remote entanglement not proven ?
« Reply #14 on: 17/04/2011 17:44:11 »
Sorry, been doing some other stuff. I will read them and see what I can make of it.  Are they experiments or suggestions by the way?
 

Offline yor_on

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Is remote entanglement not proven ?
« Reply #15 on: 17/04/2011 19:11:54 »
Maybe we are talking past each other? I understood it as if you were questioning if entanglements exist? But the paper arxiv.org/pdf/quant-ph/0503204 that you linked me too did not question entanglements, as I read it? I haven't read the other paper yet though.

As I see it a entanglement is seen to be 'set' by us measuring it. It's possible to assume that one 'twin' communicates its 'state' by mysterious means classically, but if so it has to be done inside lights speed in a vacuum, and that's what experiments sets out to disprove. By proving that the speed of light in a vacuum does not 'limit' the twins they prove a 'spooky action over distance'.

You have another type of entanglement's possible in where you get a exact, although preset, material 'copy'. A so called 'entanglement teleportation'. But as you now changed the standard to 'knowing beforehand' what 'state' this second twin will have when measuring the first, you also change the time the states take to exist. That as it now becomes what I loosely call 'meaningful information', meaning that it is preset to some state, and therefore meaningful to you and your friend.

All information sent by such 'preset' entanglement will now have to obey lights speed in a vacuum, as I understands it. That means that the entanglement no longer is instantaneous. And that is real weird :) as the only difference you introduced is forcing the particles, ions whatever, into a in advance 'known' configuration.

I'm no longer sure how you mean?

This one gives a nice description of some tests , differing between quantum entanglements and quantum teleportation's. It's quite interesting and give links, if you want to research his statements further. Entanglement by Accident.. After reading it the citation under clarifies the difference even further, and from the same author.

It's about "Chris Monroe's experiments at the University of Maryland....

... More importantly, they don't teleport atoms from one place to another. At the start of the experiment, they have a ytterbium ion in a trap on one side of the lab, and a second atom in a second trap a meter or so away. They teleport the state of one ion to another-- at the end of the experiment, the second atom is in exactly the same quantum state that the first one was at the start of the experiment. No material objects "disappear and reappear someplace else"-- you have two ions at the start, and two ions at the end, and two ions at every instant in between.

The teleportation is also not instantaneous. The quantum teleportation protocol requires information to be sent from one trap to the other at a speed less than or equal to that of light. This is fudged a little in the Maryland experiment, as the way they establish the entanglement gives them only one of the four possible output states, so they have advance knowledge of where it will end up, but in a more comprehensive system, the teleportation is not complete until a final adjustment is made to the target ion based on information obtained from measuring something about the sender. Quantum teleportation is not magic, it's perfectly consistent with both relativity and quantum mechanics.

And they're not using any mystical entanglement that dates from the Big Bang to teleport states. They have to work very hard to get the states of their two ions entangled for the experiment-- their success rate is something like one teleportation every 12 minutes. That's the main reason why their experiment is impressive-- getting the entanglement to work is a great technical achievement (as explained in my ResearchBlogging post on the experiment). It's not something that we get for free because all matter used to be in the same place fourteen billion years ago."

 

Offline sciconoclast

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Is remote entanglement not proven ?
« Reply #16 on: 17/04/2011 20:55:16 »
Good to hear from you again your_0n.

As for your statement, " I understood it as if you were questioning if entanglement exist", I am not questioning that photons can become entangled or correlated, but if remote entanglement has been proven.

The proof for remote entanglement was the violation of the Bell Inequality for correlated photon pairs.   It seemed to me that this was not a proof because uncorrelated photons from different sources also violated the Bell Inequality. Also the polarizers used in the detection can create the same affect.

Or as I stated previously, "the same 50 percent ratio applies when uncorrelated photons are tested.".  You then replied that "Its a new statement to me, and I would really be interested in seeing it proved in an experiment.".
The additional references to experiments were in answer to that request.

The experiments are described in those papers with concepts compatible to quantum theory [ more than one physicist has told me that they have described experiment in bogus quantum terms in order to get published and have the experiment results known ].  However these experiments are described, they do clearly demonstrate that the same results occur with correlated and uncorrelated photons.   By the way, there are much simpler explanations for all these results that do not rely on non-locality.     

So the bottom line is, if there is not a difference in the results between correlated and uncorrelated photons in the Bell experiments then has anything been proven.
 

Offline JP

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Is remote entanglement not proven ?
« Reply #17 on: 17/04/2011 21:41:20 »
Ok, I read one of those papers.  They're basically trying to take sources of un-entangled photons, and, by acting on those photons (through detection) to make the resulting state act like it's entangled:  arXiv.org/pdf/1001.3830

The photons themselves aren't entangled after propagation.  It appears that the resulting state of detector+photon is entangled if they throw out certain detected results.  In other words, there is a correlation between the detectors that they enforce, and that correlation makes the results appear entangled.  I'm not sure if this is actually entanglement or not, since by looking at the detection results and discarding some of them, they're making sure the states can't be in quantum superpositions, which is a requirement of entanglement.  But the basic take-home point is that they're enforcing correlations by discarding the uncorrelated results, so it isn't surprising that you see correlations.
 

Offline yor_on

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Is remote entanglement not proven ?
« Reply #18 on: 18/04/2011 01:47:51 »
No offense sciconoclast but after reading the last post I tried to Google, to see if there is a 'remote' definition that differs from what I expect of a entanglement but there seems only to exist one?

It could well be that there is a definition that I'm unaware of, but as I don't see how it differ I will stick to what I believe me to know :) What you seem to state is that there could be a correlation, as significant for originally 'non entangled' particles as for entangled, if I follow you correctly here.

If that statement is correct Bell and Aspect can't be right? That should mean that the results Aspect got, and the logic Bell followed was wrong?

Because if it wasn't they should have gotten different answers, that as it seems to me? So assuming that you are right, where did they go wrong, and why can't we see it? Notice that none of those papers state that the experiments made by Aspect is 'wrong', because if they did they would need to prove where. But they have to be wrong for this to be right, and that one needs to be answered/defined first of all I think.

To me Bells logic works, and Aspects experiment seems alright as far as I understand? when we talk about entanglement I think we in reality lean on EPR but without considering why. EPR tested 'locality' by assuming the split to create two perfectly correlated photons, indistinguishable from each other. what they protested against was the idea of a probability wave function and the subsequent collapse of the same into a observable, and lastly it was aimed at Heisenberg's uncertainty principle.

They reasoned that if you made a measurement on one of two particles, split out from one original, 'action and reaction' would guarantee that both particles flow in a equally opposite direction if 'split' in the exact 'middle' and that any measurement done on one of the particles also would define the other as they were each other 'mirrors', just traveling in the opposite directions.

And combining the knowledge of the particle they measured with the knowledge they have about 'action and reaction' there could be no question of that they if measuring the position of the right one also would know the position of the left and if measuring the right particles speed you would also know the left. In that manner they described a situation where you by measuring one of the particles actually would know all there was to know about the one not measured.

That was on a direct collision with the 'probability wave function', also described as a 'superposition' before measuring. And directly attacked the idea of it not being possible to simultaneously measure all states of a particle that Heisenberg presented, (to simultaneously know the exact position and momentum of a particle for example.) Because one of the effects of detecting one twins spin was that the other particle now was forced out of its 'hiding/superposition' as it must have a opposite 'spin' to the one detected.

"Locality is a description of the radius of action of a particle. If a particle can be regarded as a single point then the causal effects of that particle are restricted to the other particles with which it can directly interact, by coming into contact with them. For example, let us say that we measure the existence a photon by allowing it to strike a piece of photographic film – that is, we take a photograph. Each photon that impinges on the film appears as a particular dot of photographic film with a changed state; however much it may behave as a wave before it reaches the film, the final effect of each photon is local and as if it were a point or particle. Each separate photon that strikes the film is indeed local; I don't have to worry about photons on the other side of the galaxy when I take my holiday snaps.

However, in CHI we have a pair of particles that cannot be treated as separate – their states are entangled in such a way that the act of measurement or observation on one fixes a state of the other, without us having to specify in advance what state this will be. If they are not in the same place (and they are not, by virtue of being two particles) then the effect of an action on one particle is non-local – it immediately affects (according to CHI) the other particle at whatever distance it might be from the first. This is instantaneous action-at-a-distance. According to this view, my taking a photo does indeed instantaneously affect the states of all the other photons entangled with those whose state I collapse – wherever they are. Perhaps holiday snaps may be more important than is immediately apparent."


This is what entanglement is to me, a correlation 'unexplainable' other than by accepting Quantum mechanics uncertainty principle and the Copenhagen Interpretation, or if you like, Feynman's 'sum over paths' instead, but, and this people seem to forget, where all paths in fact has to be taken, for that POV to ever be possible in 'reality'.

(It's sort of fun to me how that explanation now seems to be the 'logical one' those days, but in a way it has to do with the question of how to see time. And here the all too mangled 'entropic principle' thought about concerning our arrow seem so 'local', and so makes it possible to mathematically question our arrow, transforming it into some weird temporal 'chemistry' instead :) ahem, yes, I'm old fashioned there. I put my trust in HUP :) and in that the 'arrow of time' do exist, for real, uniquely so for each and every one of us.

So I expect that anything questioning Bells/Aspects entanglements will lead them back to Einsteins view, away from both Feynman and Heisenberg and Born's probability wave function, as I see it.

To do it by restrict your experiment to 'prove' a point, instead of directly prove what you find wrong with the original statements is not acceptable to me, as that is how I infer your conclusions from those experiments. Feynman created his own alternative explanation instead, sidestepping HUP in a way, but he did that out of his genius.In Sweden we have this saying "As horned Nick cites statistics" meaning that depending on your starting presumptions, and what 'system' you define limits for, almost anything can become statistically significant (That's what Gallup opinion presentations are for :) so elegantly telling us what we think, just, depending on who pays the bill.)

To me a entanglement is a description of a absolute correlation, nothing magical, so I'm not sure where those guys math is taking them at all. I would rather see them disprove the original experiments directly (Bell Born Heisenberg Aspect etc) if now that is what they are trying to do?

 

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Is remote entanglement not proven ?
« Reply #20 on: 18/04/2011 12:10:32 »
Entanglements, as I see them, is about absolute correlations. If you assume that they have to be *identical* the question becomes. Can I by my way of 'detecting/measuring' one of them change the other one too in that measuring/detection?

If so, the next question becomes; If I can change their possible states by the way I measure, can I then do anything 'meaningful' with those changes?

Meaningful here just mean that you do something that you find use for, like sending 'energy' by injecting one 'twin' with energy as you measure it, or in some other way influence it for your later benefit. And that's where the 'grey scale' comes in? I don't know Geezer, if it is possible to do those things with a entanglement. I would logically expect it not to be possible to change them into 'useful information' as that would break lights speed in a vacuum as the 'constant' defining information transfer (speed).

So whatever they expect themselves to have done it will most probably be outside those parameters I mention here. Because if it's inside those parameters, being useful instantaneous information allowing a instantaneous information transfer, the next Nobel prize will be theirs. But I sincerely doubt that this is the case.

The correlation between those entangled particles is no magic, but some of the things we might be able to use the correlation for seems to come near at times :) As the Quantum computer idea.
« Last Edit: 18/04/2011 12:14:59 by yor_on »
 

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Is remote entanglement not proven ?
« Reply #21 on: 18/04/2011 19:01:15 »
I'm not entirely truthful there though, saying that the correlation is understandable. There is namely one more thing to this entanglement, that in a way is like 'magic'. When we split a 'wave' in a beam-splitter, down-converting it into two 'particles' that we later will measure at the detectors, we will find that no matter what 'polarization filters' we use for measuring/setting the photons 'spins/polarization', the unmeasured twin always will have a opposite correlated polarization, if measured after the first.

And this is in some way 'magical' when deemed from our macroscopic 'reality', that as the first measurement truly then 'set' both of their 'states'. That's also what the 'collapse of the wave function' is all about, as I see it. That you by measuring one can 'set' both states (collapsing both particles undefined 'superposition' if you like), without them using any means, known to us, of communicating. That we then also expect it to be a 'instant' lock-down of that spin/polarization is a direct effect of us thinking of this twin-entanglement as being 'one particle', even though displaced relative each other in time and space.

And, as I see it, it is this reason, that we by using different 'filters' can force the first photon in a defined 'spin/polarization', varying for each try, that shows us a clear 'connection' between them as the other one always when measured will have the exact opposite polarization. This is how I understands it, it also is so that QM is not, even if finding 'gravitons' or Higg, in any way a exact description of reality. Although it might be as exact a description that we can get, for those circumstances defining our 'macroscopic reality' if we get to a QM-TOE 'proving' that we have a quantified reality. But QM is in no way a finished theory, and strings and loops are a step further down in scale, surpassing QM for those trusting in it.

If QM would be true then this world is not created out of the causality chains we are used to macroscopically, as both Feynmans 'sum over paths' and HUP can show us. It's a fragmented reality where 'scale' seems to fill in the 'holes' we find at a QM level. Those working with QM will now tell you that this is wrong and that 'probability' takes care of it very well, having a clear logic to its computations. But to me that is just a step on the way. To me, and I guess to a lot of others, no 'reality' that isn't naturally existing can define the 'reality' we exist in. Unless you're prepared to lift your own existence up to that logical mathematical plane where QM exist conceptually. And I think that this, in the end, was what Einsteins main objection was about when it came to our quantum 'reality'. We exist and find a strict 'locality' macroscopically with not 'entanglements' observable, that I now of? And, until QM finds a way to prove us to 'flicker' in a experiment I will withhold that we actually do so, all of us, except possibly some politicians? Heh.

And the same reasoning, I believe, can be used for any other description expecting us to be some sort of 'projections' on that mysterious cave-wall. so entanglements are not that hard to understand, although somewhat 'magical' when it comes to how they express themselves.
 

Offline sciconoclast

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Is remote entanglement not proven ?
« Reply #22 on: 19/04/2011 16:07:17 »
Here is a really good lecture.

Anybody who is deeply involved with this topic should view the Harvard lecture by Sidney Coleman at media.physics.harvard.edu/video/index.php?:id=SidneyColeman_QMIYF.flv    as it is well worth the time.   He explains the conclusion that he shares with other prominent physicists that quantum mechanics does not permit remote entanglement and that the violation of the Bell Inequality is the product of non-entangled  quantum probabilities.

Hello Again JP.
The couple of experiments I sited are only a few of a very many similar experiments which all have the same results, but sometimes with different interpretations.   Collectively they seem to me to be experimental conformation of the view presented by Coleman in his lecture.

Hi Geezer.
You asked what is happening in the Australian experiment:   They have taken a negative or reverse blue print in the form of a photon linked to a particle from a correlated pair and then manipulated another particle into acquiring the same set of parameters, as the now destroyed other correlated particle, using that blue print.    Any reference to entanglement and teleportation  is not applicable and is hype sensationalism.

Greetings your_on.
The difference between local entanglement and remote entanglement is the difference between an actual  interrelation  and an abstract distant one.   When I went for my morning swim I encountered some sea weed which resulted in a real local entanglement.   If knowledge of that possibility would had prevented me from going for that swim it would have been a remote entanglement.

You asked for something directly discrediting the Bell Theorem.   The lecture that I referenced in this post gives a mathematical disproof for Bell's logic.

I have posted several of my own experiments on this site which may question some of the related concepts.  They are usually moved quickly to the new theories dungeon.   The latest being " Is quantum field collapse disproved by this experiment? "

Thanks for the Swedish quote.  I collect quotes.         
« Last Edit: 20/04/2011 00:11:11 by sciconoclast »
 

Offline JP

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Is remote entanglement not proven ?
« Reply #23 on: 19/04/2011 16:39:45 »
Here is a really good lecture.

Anybody who is deeply involved with this topic should view the Harvard lecture by Sidney Coleman at media.physics.harvard.edu/video/index.php?:id=SidneyColeman_QMIYF.flr   as it is well worth the time.   He explains the conclusion that he shares with other prominent physicists that quantum mechanics does not permit remote entanglement and that the violation of the Bell Inequality is the product of non-entangled  quantum probabilities.

That link doesn't work.  Do you mean: media.physics.harvard.edu/video/index.php?:id=SidneyColeman_QMIYF.flr ?

But let's back up a moment.  What do you mean by "remote entanglement?" 

Coleman is arguing against trying to explain entanglement in terms of classical mechanics.  When two particles are sent so far apart that light-speed communication isn't possible as they're observed, there will still be correlations due to quantum mechanics, even though there is no classical explanation of how they are connected.  He still agrees with entanglement existing and being a real feature of quantum mechanics; he's just against the fact that it's played up as something very bizarre, since the only reason it seems bizarre is if you try to understand it in terms of classical mechanics.  If you realize they're obeying the rules of quantum mechanics, it's perfectly natural.
 

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Is remote entanglement not proven ?
« Reply #24 on: 19/04/2011 16:42:48 »
And by the way, you seem to also be arguing against the Bell's inequalities.  Coleman agrees that they exist.  He just says that they aren't the ideal teaching tool, since there are far simpler demonstrations of entanglement, at least in the part of the lecture I saw.   (Around the 30-35 minute mark).  Can you point me to the part where he says that
Quote
the violation of the Bell Inequality is the product of non-entangled  quantum probabilities.
?
 

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Is remote entanglement not proven ?
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