Quantum Entanglement

[SilentStorm]

Could anyone with a good understanding of this topic explain it to me simply? What exactly allows the transfer of information from one particle to another?

 

[Architect]

Could anyone with a good understanding of this topic explain it to me simply? What exactly allows the transfer of information from one particle to another?

Probably best to understand the experiment (thought or actual) rather than try it from the QM standpoint.

Simply consider two particles that are paired, which means one always has opposite spin from the other. Why? Because they are, if one has 'spin up' the other has 'spin down', always. Having spin (angular momentum) just means you can deflect them in a magnetic field.

Now get two fresh particles like this, except you don't know which is which. Separate them, that is send one of them far away. Now peek in your box at the one that's left, which is it, up or down? Suppose it's down, therefore the other one is up.

That's all it is. Makes perfect sense in the classical description I just gave.

Spoiler

The QM comes in because a-priori you don't know which it is, and actually it doesn't have one spin or the other. It's actually a superposition of both. Only by testing it do the wave functions collapse and it becomes either an up or a down. And therefore, at that instant the other one becomes the other spin. So its wave function collapses too, somehow transmitting "information" across space and time.

Why is this? It just is. To understand why you can take at least four or better six years of physics. And then you probably won't understand it better but will just accept it better.

 

[Grayman]

no one really knows. Whats more they cannot read the particle without affecting it so their observations invalidate teh experiment making the whole thing complete bullshit. It's media making a story for your enjoyment.

How's that for a down the middle answer?

 

[Architect]

Thanks for coming in today.

 

[dark+matters]

https://www.youtube.com/watch?v=4Z8Ma2YT8vY

 

[Grayman]

Thanks for coming in today.

I'm not really here. The internet is just long distance spooky action.

 

[Reluctantly]

I sort of think of it as everything having angular momentum. You could deduce magnetic fields, mass, and gravitational pulls by looking at how things are rotating with one another. Quantum particles seem to be a special case of this, where the gravitational pulls are about equal and have a tendency to act like gears; so if one spins counter-clockwise, then the other must be clockwise, otherwise the gears will grind (a point of friction) and tend to re-orientate to a position with the least amount of friction as possible - having opposite spin.

So QE says that when you separate the particles, they will tend toward having opposite spin from each other, just as they did when they were together. Though of course, if you move particles away from each other, then they also have less of an effect on each other, and are effected more by their new surroundings than each other. So separate them far enough apart with enough time and theoretically they will not have opposite spin.

What's interesting is that Einstein's relativity doesn't seem to account for this, though conceptually it probably does since a changing EM field relates to a changing spin (either in space or speed) and would still fall under light being a reflection of how particles affect and change each other.

 

[Reluctantly]

https://www.youtube.com/watch?v=4Z8Ma2YT8vY

You know, I don't think I understand then. If the entanglement doesn't depend on distance or time, then are they always entangled for all existence? It doesn't make much sense if that were true, especially since it would imply that observing quantum particles doesn't cause their wave-function to collapse, that it was already there before you looked, a bit of a contradiction to quantum mechanics theory.

But if the electromagnetic link between entangled particles is so strong that you'd need to separate them by such a ridiculously large distance before they lose their pull on each other, that would seem a bit more reasonable to me than this idea of being eternally linked. I guess this would suggest that quantum particles are hard to de-entangle.

Though if I consider this with the idea that photons are the ether and those photons don't move in space, but propagate compression and expansion of space, when both particles are spinning opposite to each other, the space in between them would compress and when spinning in the same direction, the space between them would expand, relative to each other anyway. This also would imply that how each entangled particle changes (which could be thought of as time) is more dependent on each other and less affected by non-entangled particles. This might suggest that entangled particles could only be de-entangled by adding an intermediary particle that entangles with one particle and de-entangles with the other, which might explain why the distance doesn't seem to matter.

Well anyway,

 

[Anktark]

To put it really simple, we haven't got a clue. Just like with a lot of other basic concepts.

 

[Vrecknidj]

No answers from me, but, here's a good article on the topic.

http://plato.stanford.edu/entries/qt-entangle/

 

[k9b4]

dunno man but its probably just another retardedly simple observation which only appears complicated

physicists love making simple things retardedly complicated

http://en.wikipedia.org/wiki/Faster-than-light#Quantum_mechanics