Re: TECH: Quantum Head Job

From: Andrew Clough (aclough@mit.edu)
Date: Wed Oct 10 2001 - 12:56:52 MDT


At 11:39 AM 10/10/2001 +1000, you wrote:
>Folks....This really gets my atoms whizzing....
>
>put
>http://physicsweb.org/article/news/5/9/12
>together with
>Bose Einstein Condensate on a chip....(ref recent thread)
>you have.............
>
>I looked at the Quantum entanglement rig and saw a communications device. To
>modulate the carrier: Fire BEC particle laser at said entangled gas at one
>end. Demodulate other end by (someone fill in gaps here?). Bandwidth -
>possibly gigantic. Cross-Feed/Modulation disortion - Possibly Zero .

As I've always understood it, the spin of the entangled particle can't be
forced into either of the possible states. So though you may examine it,
and affect the other particle X distance away, you still can't use it to
transmit information.

Entanglement can be used to create unbreakable encryption systems,
though. You transmit a two streams of mutually entangled particles, and
then filter them in the same way, and you both have a nice stream of random
numbers that can form the basis of a one time pad. If someone intercepts
the stream to person B, they won't be able to decipher the information
without the correct filter, and they won't be able to send a correct stream
to the B, also unless they know the filter. So, communications that can't
be intercepted, but could be blocked.



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