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Theorists Make Quantum Communications Breakthrough

Posted by kdawson on from the shannon's-cat dept.

KentuckyFC writes "One of the cornerstones of modern physics is Claude Shannon's theory of communication, which he published in 1948. If you've ever made a phone call, watched TV, or used a computer, you've got Shannon to thank for describing how information can be moved from one place in the universe to another using an idea called the channel capacity. But nobody has been able to develop a quantum version of this theory. So physicists have no idea how much quantum information can be sent from one point to another. Now two American physicists have made an important breakthrough by proving that two quantum channels with zero capacity can carry information when used together. That's interesting because it indicates that physicists may have been barking up the wrong tree with this problem: it implies that the quantum capacity of a channel does not uniquely specify its ability for transmitting quantum information (abstract). And that could be the idea that breaks the logjam in this area."

4 of 155 comments (clear)

  1. Re:quantum mechanics by Colonel+Korn · · Score: 4, Informative

    Conversely if two physicists walk into a bar, how many patrons have lives?

    Answer: The same number as there were before they entered.

    In my experience physicists are generally rather cool, worldly people who have well developed personal lives.

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    "I zero-index my hamsters" - Willtor (147206)
  2. Re:Non-peer reviewed by Anonymous Coward · · Score: 5, Informative

    Most submissions to ArXiv do get submitted to peer-reviewed journals; this one claims to have been submitted in June (although they don't specify where). It's an opportunity for researchers to share their work without the delay of waiting for publication. Usually, papers there do get revised after going through the referee process.

  3. Re:Zero plus Zero equals One for large values of Z by Pinky's+Brain · · Score: 3, Informative

    Not a S/N ratio of zero, their definition of channel capacity is only very tenuously connected to Shannon's channel capacity really. Quantum channels already have 0 capacity at non zero fidelity (the quantum equivalent to S/N). The 0 capacity channel from this paper aren't 0 capacity because of their fidelity though, the channels are 0 capacity for different reasons.

    So it's not really directly applicable, "just" interesting math.

  4. Re:So 0+0=1! by mad_robot · · Score: 3, Informative

    1=0+0!

    There, fixed that for you.

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