Quantum Entanglement?

[seer]

My understanding is that something may be traveling instantaneously between the to particles but whatever that may be cannot be used for carrying a communication channel.

What could possibly be traveling instantaneously ?

[JonF]

AFAIK whatever's happening may not be a particle and may not have motion to measure.

ETA a couple of interesting articles: No-communication theorem, What is quantum teleportation? Why can’t we use it to communicate faster than light?.

[seer]

AFAIK whatever's happening may not be a particle and may not have motion to measure.

?????

[JonF]

I don't see anything particularly difficult to understand. Somehthing's happening. We don't know what it is, therefore it may or may not be a particle. Particle or not, it may not move and therefore measuring its motion may not be possible. See the links I added above.

[klaus54]

What could possibly be traveling instantaneously ?

Apparently the state of entangled particle is what's "traveling" instantaneously. QE is an aspect of existence we don't understand very much at the moment. It's likely something that will come down to "interpretation" like other aspects of QM.

As far as a coding system, I would think that groups of entangled particles would have to be close enough together at their "ends" so that two or more sets of EPs could send information among "ends" in the usual way but restricted by c in the classical sense.

K54

[Sparko]

?????

It is the spin of the two particles that are linked. If one has a certain spin, the other will also have it.

From what I have read is that there is no way to know which way either particle spin is unless you measure it. Until you measure it, there is a 50/50 chance that it is spinning one way or the other. Once you measure one of the particles, the other particle's probability collapses to have the same spin. So someone measuring particle A and seeing a right spin, will mean that particle B has a right spin too. Or if someone measures particle B and gets a left spin, then particle A will have a left spin. But until one of the particles is measured there is no way to know which spin either article has. You can't put a spin on a particle and force it to make the other particle spin that way too (which you would need to do in order to transmit information) - they are linked but random in other words.

At least that is what I gather from reading about it. I am no physicist by any means.

[firstfloor]

Yes, still I don't get it. The particles in the OP were separated by three meters. They are not a coherent system in that they have physical contact. They don't. And still something travels instantly between the two particles.

I’m not sure that anyone gets it. The formalism means that widely separated (no limit as far as I know) entangled particles are described by a single wave function. This superposition means that information obtained by measurement of one particle also gives information about measurement of the remote particle.
This might help:-
http://faculty.luther.edu/~macdonal/Spooky.pdf
“Are you asking yourself how the entangled particles achieve the correlations predicted by quantum theory? Don’t. Richard Feynman, who won a Nobel Prize for fundamental contributions to quantum theory, warned “Do not keep saying to yourself, if you can possibly avoid it, ‘But how can [quantum theory] be like that?’ because you will get ‘down the drain,’ into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.” “

At least, not yet. We live in hope.

[seer]

“Are you asking yourself how the entangled particles achieve the correlations predicted by quantum theory? Don’t. Richard Feynman, who won a Nobel Prize for fundamental contributions to quantum theory, warned “Do not keep saying to yourself, if you can possibly avoid it, ‘But how can [quantum theory] be like that?’ because you will get ‘down the drain,’ into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.” “

At least, not yet. We live in hope.

Yeah, well this stuff is weird.

[seer]

It is the spin of the two particles that are linked. If one has a certain spin, the other will also have it.

From what I have read is that there is no way to know which way either particle spin is unless you measure it. Until you measure it, there is a 50/50 chance that it is spinning one way or the other. Once you measure one of the particles, the other particle's probability collapses to have the same spin. So someone measuring particle A and seeing a right spin, will mean that particle B has a right spin too. Or if someone measures particle B and gets a left spin, then particle A will have a left spin. But until one of the particles is measured there is no way to know which spin either article has. You can't put a spin on a particle and force it to make the other particle spin that way too (which you would need to do in order to transmit information) - they are linked but random in other words.

At least that is what I gather from reading about it. I am no physicist by any means.

Yes, but how does particle A have any effect on particle B if there is distance between? Where is the physical connection? In the link from the OP the two particles in question were separated by three meters. What is interacting between or going between the two particles?

[Sparko]

Yes, but how does particle A have any effect on particle B if there is distance between? Where is the physical connection? In the link from the OP the two particles in question were separated by three meters. What is interacting between or going between the two particles?

Magic and unicorn farts.

[seer]

Magic and unicorn farts.

Yeah, might as well be... This hurts my head!

[Sparko]

or maybe it is something like this...

think of space as a sheet of paper. bend the sheet of paper into a U shape.
Stick a needle into the paper so it skewers the U, penetrating in two places.

Turn the needle clockwise and it is turning clockwise at both intersections at the same time. We can only see the intersections with space (we call that a particle) and not the needle itself. But they are basically part of the same "object" if you look at it from the outside.

[JonF]

Yes, but how does particle A have any effect on particle B if there is distance between? Where is the physical connection? In the link from the OP the two particles in question were separated by three meters. What is interacting between or going between the two particles?

Damn good questions. We don't know. We may never know. The math works, the experiments are clear, but that's all we got. Quantum stuff is weirder than snake's suspenders, and is so far removed from our everyday experience that it's quite possible we can't truly understand it.

And many physicists think that before the measurement it's not a question of not knowing the entangled particle's property value, it's that the property does not have a value until it is measured.

[seer]

Damn good questions. We don't know. We may never know. The math works, the experiments are clear, but that's all we got. Quantum stuff is weirder than snake's suspenders, and is so far removed from our everyday experience that it's quite possible we can't truly understand it.

I mean if the experiment in the OP is correct, we see the actual physical manifestation of this. It is actually happening. So how can we conclude that nothing travels faster than the speed of light - obviously something is traveling faster than that -instantly as a matter of fact.

[seer]

or maybe it is something like this...

think of space as a sheet of paper. bend the sheet of paper into a U shape.
Stick a needle into the paper so it skewers the U, penetrating in two places.

Turn the needle clockwise and it is turning clockwise at both intersections at the same time. We can only see the intersections with space (we call that a particle) and not the needle itself. But they are basically part of the same "object" if you look at it from the outside.

Do you want me to go mad now, or should I wait to later? Just asking...