Creating Quantum Entanglement

derubergeek writes "APS has a summary of a paper being published in the Dec. 30th Physics Review Letters on the possiblity of creating quantum entanglement of particles traveling at speeds less than the speed of light. They believe there may be practical applications in satellite synchronization, for example."

Comments

Abstract

[Henry V .009]

ABSTRACT:

We study the properties of quantum entanglement in moving frames, and show that, because spin and momentum become mixed when viewed by a moving observer, the entanglement between the spins of a pair of particles is not invariant. We give an example of a pair, fully spin entangled in the rest frame, which has its spin entanglement reduced in all other frames. Similarly, we show that there are pairs whose spin entanglement increases from zero to maximal entanglement when boosted. While spin and momentum entanglement separately are not Lorentz invariant, the joint entanglement of the wave function is. ©2002 The American Physical Society

What this is saying--I'm guessing--is that an entangled spin state for two particles wouldn't look as entangled anymore for a moving observer (relativity). A classical (relatively--ha ha, double pun) analogy would be how electric fields look like magnetic fields to moving observers.

The interesting thing is this "boosting". They're saying, I guess, that there are refrence frames from which particles look far more entangled than the rest frame.

I'd like to close this post by pointing out how highly unethical it would be for some slashdot poster with an account for Physical Review to post the full text of the article as an AC. It would be entirely wrong to think of that as "liberating" some piece of research funded by U.S. taxpayer dollars. Furthermore, those of us interested in the article but lacking accounts or easy access to a college library to read it would not be at all grateful.

Re:Abstract

[derubergeek]

I'd like to close this post by pointing out how highly unethical it would be for some slashdot poster with an account for Physical Review to post the full text of the article as an AC. It would be entirely wrong to think of that as "liberating" some piece of research funded by U.S. taxpayer dollars. Furthermore, those of us interested in the article but lacking accounts or easy access to a college library to read it would not be at all grateful.

Fine. Here's a link you ungrateful bastard.

Re:Fast internet?

[Alsee]

Could this be used for extending the internet to other planets?

No.

Using entanglement two people can "aquire" identical information instantaneously no matter what the distance. The problem is that the information they both get is completely random. You can't "send" any sort of message. You can only both recieve identical random data. That makes it useless for communication but perfect for cryptography. You take the random data and use it to encrypt a message and send the encrypted message through normal channels.

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