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Quantum Information Can be Negative
nerdlygirl writes "In a development that would probably even puzzle Claude Shannon,
information can be negative -- at least when the information is quantum.
The discovery, by
Horodecki, Oppenheim, and Winter, appears in the
current edition of the leading journal Nature.
If I tell you negative information, you'll know less. Apparently, researchers hope to use this to gain deeper insights into phenomena such as quantum teleportation and computation, as well as the very structure of the quantum world. More details can be found here and
here
A popular account of the article can be found on Oppenheim's
homepage, and a free version of the article can be found in the arxiv for those of us
without subscriptions to Nature."
If I tell you negative information, you'll know less.
I don't think that really works. You can't make someone know less by just telling them something, unless by doing so you somehow alter their brain chemistry to store less information or remove information already stored. I suspect this might be closer to the quantum idea.
Suppose you have two pieces of quantum information, one positive and one negative. The negative piece could negate the positive one which would result in 0 total pieces of information instead of 2.
However, the idea of this negative information is still kind of abstract and not that easy to understand. The quantum nature of this is key I think. It doesn't look like it extends that well to our concept of information (which would be the kind stored by the brain), at least not yet.
The article calls this a measurement of the quality of the information, which they say has no bearing on the quantity. The thing about quantum information is that due to the fact that the amount of information contained can lessen by measuring the information, it is actually possible to know more about a quantum object than actually describes it. Think of it more like looking at a comet in space. You can learn more about it by hitting it with explosives and measuring the spectral result, but in doing so you are actually destroying bits of the comet. So eventually, you can know all about an object that doesn't actually exist. Of course, unlike comets, quantum objects can be both there and not there at the same time; the time factor of it being destroyed after it has been measured is effectively removed.