Quantum Entanglement - what is it?

"Spooky Action" discussion. Starting with some background: what really is "entanglement" ... ?From wikipedia
Entanglement - Wikipedia Let us assume I have several pairs of gyroscopes, each pair is in a different orientation than the other pairs, but each pair has the same axial orientation and the opposite spin of the other at the moment of their 'activation/creation/spontaeious assembly' and that each pair is in boxes such that I cannot determine the spin\orientation without opening the boxes.Whenever I open one box, I can observe the {spin\orientation} of the one and predict the {spin\orientation} of the other -- provided that no action has been taken to change either gyroscope in between 'activation/creation/spontaneous assembly' and 'observation/measurement' ... "this despite the fact that it is impossible to predict, according to quantum any mechanics, which set of measurements will be observed ..."How is this any different? Why should anyone be surprised that such pairs exibit such results?{is it science forum?}

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

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RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
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Might your new topic material tie into the Quantum Interference topic?If not, we can give this one a promotion.Adminnemooseus

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Not really the same. That is a special case further down the road, and quite possibly a side road.I wanted to establish that there is no fundamental wonder to quantum pairs, because they are made that way.It doesn't matter how separated the pairs get they each have the same predeterminations similar to the gyros.

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

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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.

This sure seems very remote to considerations of any variety of evolutionary theory, not that such topics are uncommon at . Do we need a forum such as "Science having nothing to do with Creation/Evolution"? By the way, any discussion of the above statements should go to the "Considerations..." topic, link below.Adminnemooseus

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Thread moved here from the Proposed New Topics forum.

Hmmm... it's subtle, but there is extreme fundemental wonder Demonstrating it is not quite as easy as I would like, but I will have a go. May take a while to set up some diagrams...As with most of the oddities of QM and particle physics, the weirdness only reveals itself in probabilities. But this is sufficient, as long as you are prepared to do some thinking...Your gyroscopes are classical and cannot exhibit the behaviour we will discuss.

I don't think I really understand quantum entanglement but from my interpretation of it, I think your gyroscopes are a bad analogy, no offense. Maybe I'm not understanding the analogy correctly but it doesn't seem to be the same as what I've come to understand quantum entaglement to be.

A rough ananlogy of entanglement is imagine two entangled dice. Observe the throws of one or other and the outcomes are purely random. But observe the behaviour of the two together and you see correlations. Remove them to opposite sides of the universe and the correlations continue. How? Magic I'm drawing up a real example of entanglement for you but will take a few more hours as I have a lot on...

quote:

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How is this any different? Why should anyone be surprised that such pairs exibit such results?

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The difference is that the orientation of a subatomic particle does not exist until you measure it. Once you measure it, then the particle has a definite orientation. But, since angular momentum is conserved, once you have determined the orientation of the one particle, the orientation of the other particle is now determined.What makes this "spooky" is, repeating the classic EPR thought experiment, you can prepare these two particles in a laboratory. One particle remains in the lab, trapped in your apparatus. The other one escapes and zips off into space at a speed near the speed of light. You wait for a year, and, assuming that no perturbations have occurred to either particle, you finally getting around to measure the orientation of the one particle in your laboratory.Before the measurement, neither particle has a definite orientation. Now that you have measured the orientation of the particle in your laboratory, it has a definite orientation. Because of the conservation of angular momentum, the other particle, now almost a light year away, must have the opposite orientation, and since we know what it's orientation is now, it must have acquired this orientation instantly, once you made the measurement in your laboratory.Yet, how does the distant particle know what orientation it is supposed to have? According to the Theory of Relativity, the particle could not have recieved this information from the particle in your laboratory -- information cannot travel faster than the speed of light. Yet, determining the orientation of the particle in your laboratory instantaneously determines the orientation of the distant particle.

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"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)

How do you know, before you measure it, that the particle does not have a definite orientation?

More soon (couldn't be any less...)

Looking forward to cavediver's explanation, but if anyone wants to jump the gun they should look up Bell's Inequality.It shows that there are statistical differences in the two situations, ie, having definite orientation the entire time or having undetermined orientations the entire time.

Exactly. It is Bell's Theorem that removes the possibility of "hidden variables" that could "carry" the correlations. But this is STATISTICAL. It cannot be observed in one observation.

Ok, here goes... (grateful thanks to Prof David Mermin)

_____                                    _____
  =R|1 2 3|/                T               \|1 2 3|R
   G|   / |           <~   >O<   ~>          | \   |G=
    |_____|\                                /|_____|

Now you have to like that We have got an emitter in the middle, which upon the press of the button emits two "things" in opposite directions towards two detectors.The detectors are identical, and each have a 3-way switch for settings 1,2 and 3, and two light bulbs, red and green. When a "thing" enters a funnel on the detector, one of the two lights illuminate.THERE ARE NO HIDDEN CONNECTIONS ANYWHEREOk so far?The experiment is simple: we select a switch setting at random on each detector, press the button on the emiiter, and record which lights illuminate. The situation depicted in the diagram would be recorded as 31RG for reasons that I hope are obvious. After many many many trials of the experiment we have some data:If you ignore the switch settings, all four light combinations occur randomly and evenly. If you observe just one detector, the string of results: RRGRGRGGGR... occurs randomly and evenly.First amazing fact: whenever the switches are in the same position (11 22 or 33) the lights are the same colour!!!!Amazing? Really?YES! Because (of the times when both switch setting are the same) 50% of the time they are both red and 50% of the time they are both green... Think about it... how do they know to do that?End of Part 1Edited by cavediver, : No reason given.Edited by cavediver, : Clarity following Para's question...

I gather you mean for one and the same switch setting?