Quantum Entanglement - what is it?

Yes, so a string of observations for this might be:11RR 33GG 22RR 22GG 33GG 11GG 22RR 11RR etc

I'll start here, but respond to everyone ... so far ... This response is classical as well ... -- thanks for posting btw. Excuse me while I put on my 'devil's advocate' horns ... They aren't just gyros, but gyros in black boxes. They are 'indeterminate' externally until measured. Still when you measure one orientation, you will instantly know the orientation of the other of the pair, no matter which pair you measure or where they happen to be. This is the point the analogy is designed to show. Let's call this state "coupled" for the sake of argument, as it demonstrates that both parts act as a "coupled" pair, whether in the same room or across the galaxy. It is a condition they are "born" with. Yes indeed. The way I would state it is that "you don't know what orientation you will measure until you measure it" rather than it doesn't exist (for you don't know that either - I also don't know of any particles that have been measured as NOT having an orientation).Just as with the gyros, you don't know what orientation you will measure until you measure it. And when you measure one you instantly know what the other one is, because they were "born" that way, as pairs, "coupled" ...It could be that particles don't have orientation - but that when we 'measure' them, that action causes a reaction that is interpreted as orientation. The fact that the same reaction occurs from a "coupled" pair would not be a great surprise either.Now, to demonstrate that the particle could have any of a variety of orientations you have to be able to measure it in a non-destructive way several times and get different results. So far all the results I have seen show that repeated measurements on the same particle give the same orientations (except of course where the action of measurement changes the particles orientation .... such finicky critters)Or, this could (theoretically) be demonstrated by measuring one of a "coupled" pair and then measuring the other at different time intervals and getting different results. If we know they are made "coupled" and that they have the same forces etc acting on them, AND if one is in a condition of changing orientations then the other would be in one as well, and the time of measurement would then affect the observed orientations and show change.If you don't get different results (and you don't) you can conclude that (a) they have that orientation from the start - they are "coupled" - and you've only confirmed what it is, (b) 'classic' entanglement - measuring one forces the other to collapse into the proper corollary state - and you've observed one of many possiblities, OR (c) something else is happening. Are you saying one di affects the behavior of the other here? Or that you get the results because they do not affect each others behavior no matter how near or far they are (it's just the way things are)? Or is the pattern of correlations only in the eye of the beholder? Thanks, I have looked it up, and was unconvinced. This is, in fact, where I started with this. It could also be that you are not measuring what you think you are measuring. Bell's Theorem arbitrarily assumes three conditions to get the pattern of nine possible combinations and the 5/4 inequality. There's the rub eh? Are the patterns from reality or from the chosen statistics? The "correlations" of the dice? Or once again you are only measuring the original 'coupled' behavior of the particles. I read that as whenever you had setting 1 you had 50% red and 50% green ... on both detectors.What I find curious is that you are supposedly measuring three states with a binary measurement.The fact that you are getting a 50:50 split to me says you are measuring a (probably) even number of states (at least two, possibly four, maybe six, etc) that lump into two even groups, one red responding and one green responding. You could even have six states that are divided into three different sets of two equal groups by each switch position. And if this is the case then the basic premise of Bell's Theorem is not valid and the conclusion is false.Any even number of possible states being measured ends up with a 50:50 split. Only odd numbers end up with an 'odd-man-out' inequality, where 1 is a null\limit solution and three has the largest (measurable) inequality ratio, and the rest tending to a 50:50 limit condition as the number of states approaches the odd infinity.It is not the switches that do the measurement, it is the redness or greeness that is measured: two states. 50:50.Color me red or green, but not impressed.Enjoy.Edited by RAZD, : typo

---

Join the effort to unravel {AIDSHIV} with Team EvC! (click)

---

we are limited in our ability to understand
by our ability to understand

​

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

quote:

---

The way I would state it is that "you don't know what orientation you will measure until you measure it" rather than it doesn't exist.

---

You could state it that way, but then you would be wrong. According to the accepted Copenhagen interpretation of quantum mechanics, the particles do not have a definite orientation. Or, to be more accurate, they exist in all the possible orientations at the same time.-

quote:

---

Now, to demonstrate that the particle could have any of a variety of orientations you have to be able to measure it in a non-destructive way several times and get different results.

---

This is actually done all the time. The interference effects that one observes in quantum mechanical systems arise because the particles exist in all the possible states and these states cause the interference effects.But the actual clincher is Bell's Theorem. We have two possibilities. The particles actually do exist in a definite orientation even if it is impossible to know in which orientation. In this case, Bell's Theorem predicts a certain result in the experiment cavediver is describing.Or the Copenhagen interpretation is correct, in which case the particles do not have a definite orientation at all. In this case, Bell's Theorem predicts a different result in cavediver's apparatus. So, all that needs to be done is to set up cavediver's experiment and observe the results.Which has been done. Many times, and at increasing accuracy. And so far the results favor the Copenhagen interpretation. There are no "hidden variables" -- the particles do not have a definite orientation until the orientation is actually measured.Just like an electron trapped in a box does not have a position (or, more accurately, it is everywhere at once!) until its position is measured. Nor does it have a definite angular momentum (it has all possible angular momenta all at once!) until it is measured.It is, indeed, a strange world in which we live.I hope cavediver is not yet finished with his nice example. He has done a great job in describing the experimental apparatus in confirming Bell's Theorem; I hope he will then continue to describe Bell's Theorem so even I can understand it.

---

"We must respect the other fellow's religion, but only in the same sense and to the extent that we respect his theory that his wife is beautiful and his children smart."
-- H. L. Mencken (quoted on Panda's Thumb)

This is getting a little away from the issue. The point is that the particles are "coupled" when they were "born" and the only observed result of that, that I can see, is a confimation of them being "coupled" and acting in just the expected way any "coupled" pair would be expected to act.I find nothing surprising in two particles made to behave in a set way, and then finding (lo and behold) that they behave in a set way. But you don't know this ... until it is measured ... and that is my point: "you don't know what orientation you will measure until you measure it" -- the only thing you know is that you will measure an orientation, eh?

---

Join the effort to unravel {AIDSHIV} with Team EvC! (click)

---

we are limited in our ability to understand
by our ability to understand

​

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

So what is the connection between the switch setting and the color?

RAZD against the world again it's been a while... How could it? They are causally separated. Yep, they are entangled. Not easy to do with a pair of dice But very easy with the things popping out either side of my emitter. Absolutely not. There will be a definite observable probability: P(A=B) which will not be 1/6. Cool, Nobel Prize looming I feel Where did you look it up? Explain please... No, it doesn't. It considers all classical possibilities of encoding the data. Where are you reading this? The patterns are from the entangled wavefunctions of the two "dice". Possibly Now how is this coupling encoded?

Ok, let's look at this...The lights are the same whenever the switches are the same, but we don't know whether it will be GG or RR.So the obvious conclusion is that the "things" have some internal state that they share when they are created, and they each carry this state to each detector.Given that we see different responses (RR, GG) each under the three different switch settings (11, 22, 33) means we have quite a few possible states:GGG GGR GRG GRR RGG RGR RRG RRRSo GGR means "I am Green if the switch is at 1 or 2, but I am Red if the switch is 3"A state is picked at random by the emitter, attributed to the two "things", and they carry the state to the detectors that ensures that they light the same colour when the switches are in the same position.Of course, if the switches are in different positions, you will get a mix of same colour and different colour, e.g. GRG and switch positions 1,2 gives 12GR; RGG and switch positions 2,3 gives 23GG.Is that ok? Sort of what you were thinking?Now just ensure that your coded states give the correct observed statistics of the lights overall: equal numbers of red and green randomly distributed. Or taken in pairs: equal numbers of RR, RG, GR, GG - that is, 50% same, 50% different.Have you done it? Yes? We have a new Nobel Laureate in our midst Let's just check the state coding above.Of the nine possible switch settings, RGG gives11RR
12RG
13RG
21GR
22GG
23GG
31GR
32GG
33GGSo 5 same and 4 different -> 55.5% the sameOk, now for the others. All the two colour states give this 55.5% the same. But then the two left (RRR and GGG) give 100% the same!!!So we have well over 55% of the colours the same predicted by our coding.The experiment gives precisely 50% (+/- 0.000000...% or however close you want by running millions of trials).55% is close but no cigar.Can you do better? Nobel Prize if you can...
Can you reproduce the experimental data with classical "things"? Nobel Prize if you can...Bell's Theorem: There is no coding that allows you to simultaneously have both the 11RR 11GG 22GG behaviour and the 25% GG, 25% GR, 25% RG, 25% RR behaviour. So how do both lights know to be the same colour when the switches are the in the same setting???As as said before... magic Or as I like to call it... mathematics Edited by cavediver, : Because I canEdited by cavediver, : Clarity

The "things" are entangled photons. The switch settings decide whether you apply a polarising filter vertically (0 degrees), left (-120 degress) or right (+120 degrees). Green light means photon passed through the filter. red light means photon did not pass through filter.Edited by cavediver, : No reason given.

Thank you. How is it encoded in the blackbox gyros? It is just a 'relic' or condition of their being made the same at the start. Take the gyro boxes ("GB"s) send them through the detectors, the detectors measure spin direction by the extremely weak magnetic fields produced by the rotations of the dense metal ring (similar to earth?).Switch 1 measures spin "X"ness - alignment to the x-axis of the experiment with positive or negative for the (slightest)"north" pole directionSwitch 2 measures spin "Y"ness and Switch 3 measures spin "Z"nessObviously the "coupled" GB's will give exactly the same results from each detector when they have the same settingsObviously you will "get" the same grid with 5/4 breakdown of all "combination possiblities"Obviously you are not measuring three states, but only two -- the {up\down}ness of the spin relative to the sensor, hence the 50/50 results. oh. my. looks like you can change {X}ness to vertical, {Y}ness to left (-120 degress) and {Z}ness to right (+120 degrees) ... same results, plus guaranteed overlapping sensor readings.Enjoy.

---

Join the effort to unravel {AIDSHIV} with Team EvC! (click)

---

we are limited in our ability to understand
by our ability to understand

​

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

Yes, and it is precisely this you are trying to avoid My experiment doesn't give a 5/4 breakdown...Try it. Put some test data through and we'll have a look. You don't ned to make up too many random gyros to start to see the pattern emerge...Edited by cavediver, : No reason given.

I should point out to everyone that RAZDs example is a perfect embodiment of the coding we used earlier. And it falls perfectly into Bell's Inequality. Raz's experiment will produce 55%+ same results (both detectors measure spin up or both measure spin down) as predicted by the Inequality.Of course, what we see in the photon experiment is 50%. This is impossible to achieve classically...

why thank you sir But all credit to David Mermin who came up with this nice jargon-free expression of the Stern-Galach EPR experiment. If you ever get the chance to read "Boojums all the Way"... some gems in there. A great essay on the role of punctuation in mathematical journal typesetting How did I do? I know it's all a bit hidden in the probabilities. There is no great da-da!!! At the end of the day, all that is happening is that two things which are mutually exclusive at the classical level are gaining an area of overlap in the quantum regime.Edited by cavediver, : No reason given.

Please read that section again. You have exactly the same 5/4 breakdown of all "combination possiblities" -- I'm NOT talking the test results here, but the predicted outcome, based on an assumed three state measurement. Thank you. I thought it was a pretty good match, given the totally bad analogy ... False.You will test a 50:50 result in actual practice with the GB's just exactly as with your photons.The reason is that you are NOT testing (measuring) three states as the premise of Bell's Theorum assumes, but only two -- redness\greeness, upness\downness, pass\fail, +/-, etc.... Unless what you are measuring is NOT what you think you are measuring.This is the classic "5/4" grid:Where "S" is the same result and "D" is different result, based on the prediction of the theorum.Let's rotate those GB sensors a bit and add one: rather than aligned on X-Y-Z axis we now use the axis of a tetrahedron (from center to each of the 4 points). Each axis is the same degree of separation from the others.Now we get a 8/8 grid:Which now predicts a 50:50 distribution so there should be no wonder when that is observed ... but the logic is just as false as in the 3x3 grid.This should cause most people to start questioning what the grid really means. (As in how does 1-3 get to be "S" when 1-2 is "D" while mathematically there is no difference between 1-3 and 1-2 ... other than 1-1, 2-2 and 3-3, which just confirm the "coupled" behavior of pairs, the other "S" and "D" assignments are arbitrary and bear no relationship to what is really being measured.)What are we really measuring?Logically, what is important is that what the detector measures is redness\greeness, upness\downness, pass\fail, +/-, etc. -- each sensor divides the random samples sent to it into two groups, with a 50:50 probability of each particle being measured\tested, falling in one group or the other, regardless (ie - independant) of the orientation of the sensor.Back that up a tic... take each sensor and record all the results sent to it: you get a 50:50 split. You could run a thousand tests, arbitrarily spin the detector, do another thousand tests, repeat the detector totally random spin and another thousand tests.Result ... 50:50 split.What you are really measuring is two states not three. A more realistic test grid (that covers sending "coupled" particles to each detector) is: Where "2" gives the opposite result compared to "1" (ie polarized plates at 90^o) and the results are 2/2 or 50:50, still predicting the actual outcome, although it is really a null solution, a tautology in information content.I'm still unimpressed.Rather than a test of entanglement, I see confusion in the predictions and assumptions. So far all I see is predictably "coupled" behavior of intentionally "coupled" particle pairs, and no magic behavior.Enjoy.{abe} What you really get with the 3 switches is plus plus Obviously resulting in a 50:50 distribution.{/abe}Edited by RAZD, : added material at end

---

Join the effort to unravel {AIDSHIV} with Team EvC! (click)

---

we are limited in our ability to understand
by our ability to understand

​

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

So am I with your grasp of what's going on but we'll get there...Or you'll get the Nobel. Are you a betting man RAZD? I've got 100 to the charity of your choice waiting here...But it will have to wait as it's 2am and I'm wacked. Perhaps you can explain how on earth you get 50% same and 50% different while I sleep. 50% up/down from one detector is a given and obvious... Show me some (imaginary) data.And why is 12 or 21 always different? That is not the case with your Gyros. They can be different or same depending on orientation... The orientations wrt x y and z are all independent.

Just as a quick addendum before I drop off...The mechanics of this don't matter a damn. The number of states is immaterial. And forget arguing with the number of switch positions. I have described the real apparatus of a real experiment. I have described the real data: random streams of 50% R, 50% G from each detector AND when observed as pairs from detector 1 and 2, 50% same and 50% different WHILE giving the same result whenever the switches are in the same position.You CANNOT ascribe any method of encoding for this result. As described, I have no idea what is being emitted, what is being measured, what the switches do, what the lights mean... and I don't care. All that matters is the output and your ability to replicate that output classically. You cannot. It really is that simple.Edited by cavediver, : damn has an n at the endEdited by cavediver, : No reason given.