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Re:'Second Earth' found, 20 light years away by icey on Tuesday October 16, 2007 @12:57PM (#68615)
Does anyone know if quantum entanglement has been proven enough to allow for at least a glimpse of being able to make data transmission occur at "faster than the speed of light"?

I mean, if a quantum object represents a bit, and gets flipped here; and its counterpart is on... Mars; the counterpart should get flipped instantly, no?

Re:'Second Earth' found, 20 light years away by Retric on Tuesday October 16, 2007 @01:34PM (#68641)
There is no flipping of data it's more like you hand 2 people (Bob and Ted) a box with the same number in it. They walk to other sides of the world and then Ted opens his box. As soon as Ted opens their box they know what is in the other box but that has nothing to do with the speed of light and there is no way for Ted to use what he knows about the number in Bob's box to send Bob new information.
Re:'Second Earth' found, 20 light years away by hugh on Tuesday October 16, 2007 @04:13PM (#68718)
That's not quite the right analogy -- it misses the point a bit. In that analogy the two numbers have definite values right from the start -- they're just ordinary boxes with ordinary numbers written in them. In a more quantum mechanical analogy, the numbers inside the boxes would be undetermined until the observation was made, and yet you would always find that the boxes had the same number inside, even if they were opened simultaneously and many light years away from each other.

Under the Copenhagen interpretation of quantum mechanics, there is in fact some kind of spooky "instantaneous" communication going on between the particles -- one of them needs to tell the other "oh no, my wavefunction has just collapsed in such-and-such a basis and your value now has to be |X>".

Complicating this even further is the fact that relativity tells us there's no such thing as "simultaneity" when we're talking about things happening at different points in space, and so while it looks to one observer like the faster-than-light signal must have gone from Ted's box to Bob's box, to an observer moving relative to the first observer it might look like the faster-than-light signal actually went from Bob's to Ted's.

Some other interpetations of quantum mechanics (in particular, no-collapse aka "many worlds" interpretations) this faster-than-light signalling doesn't occur... though these interpretations have other counter-intuitive features instead.

Even if there _is_ faster-than-light signalling between particles, though, you still can't use this to send a message, because the information you get is always just a random string of bits -- there's no way to actually send useful information.

Re:'Second Earth' found, 20 light years away by icey on Tuesday October 16, 2007 @02:52PM (#68681)
Gah, Okay; This is why quantum mechanics drives me nuts. I guess what confuses me is if the state in Bob's box changes, then the state in Ted's box should also change as well regardless of distance.

However, reading a little more about the quantum teleportation process leads me to believe I'm wrong on this.

http://en.wikipedia.org/wiki/Quantum_teleportation

Thanks for the great explanation, btw.

Re:'Second Earth' found, 20 light years away by inklesspen on Tuesday October 16, 2007 @01:25PM (#68633)
IIRC, entanglement does not allow for communication of data.
Re:'Second Earth' found, 20 light years away by jkush on Tuesday October 16, 2007 @01:03PM (#68620)
Theoretically it will work, but the problem is getting the counterpart there. If you want instantaneous communication to something 20 light years away, you've got to travel 20 light years to get it there first.