

Quantum Weirdness: Two times zero doesn't always equal zero - soundsop
http://www.spectrum.ieee.org/aug08/6609

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lisper
You don't need quantum mechanics to produce this kind of a result. One-time-
pad encryption does essentially the same thing. Both the "key" and the
"ciphertext" (I put them in scare quotes because they are mathematically
indistinguishable) by themselves are just random bit strings containing zero
information. But together they contain all the information of the original
cleartext.

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soundsop
I don't think that's a correct analogy. This announcement is about signal
detection in the presence of noise not information decryption.

My interpretation of the article is that two noisy quantum channels (where
each individual channel is too noisy to recover any information) can have
their noisy results combined to recover clean information.

There is no classical analogy to this case. If two classical channels are too
noisy to recover information from them individually, then there is no way to
combine the noisy results to recover any information.

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boredguy8
Umm, isn't this what Bell Labs found under Gell-Mann in like 40 years ago? You
overcome transmission problems with redundancy. Or am I missing something?

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braz2
Actually no... They were not trying to overcome noise. They were actually
testing what can come out of combining "entangled" noisy channels. The fact
that they retrieve information out of nothing (noise is the equivalent of
"nothing" information-wise) is the beauty of their work.

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ars
Isn't this the same as spread spectrum broadcasting?

