Slashdot Mirror
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."
Initially, I believed that negative information was an abstract math concept, but after a significant amount of additional study I've determined rather conclusively that it exists in our frame of reference and that the effects are actually easy to detect. The trick is to *locate* some of this negative information. Fortunately, I've managed to work that out as well -- I'm not publishing for a few months yet, but I figure I'm far enough along to spill some of the beans:
Experiencing negative inforamtion is all about occupying a point in space and time which intersects with the negative information stream. This was initially tricky, but through months of tireless research I've worked out the optimal conditions: I find that your best chance of encountering it is roughly around 1 AM when you're at the bar with your friends after a long night of drinking and one of them says something along the lines of, "Awright! Time for some shots!"
Bang! Negative information. What happened after that? How did I get home? All lost in the quantum flow, never to be accurately described by anyone involved (except, occasionally and for reasons I still haven't managed to factor into my equations, the bouncer and the police). I assume the headaches and liver damage are just a nominal side effect.
Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
After trying to read those articles, I do feel like I know less.
Forget the whales - save the babies.
Of course negative information is cool, but it would be even cooler if you could combine negative information and positive information to produce a huge explosion.
cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
Since a black hole's entropy is directly proportional to it's information content, this, if true, would have an effect on black holes.
If I recall correctly (and I may not -- my physics isn't what it used to be), the amount of information contained by a black hole is directly proportional to its surface area -- specifically, I believe that the total number of bits contained is equal to 1/4 of its surface area as measured in Planck units.
Now, if information can be negative, that would provide another method of shrinking a black hole, in addition to Hawking radiation.
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
(-2)+(-3)=+1
I think you've hit the lower limit already....
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.
(-2)+(-3)=+1
You have obviously received a lot of negative information before you started writing this 'math'.
No sig today.
I distinctly remember a lecture by Feynman at Caltech in the early 1980's where he talked about negative information (probability). I am sure I still have notes for it somewhere. Of course, you can never see negative information; any actual measurement has to have positive probility. But it can give quantum interference effects in measured quantities.
Feynman presented it as just a different way of having quantum interference, from negative probability instead of complex amplitudes.
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.
Depends on what you're doing. (-2)+(-3)=+1 is Slashdot Moderator Math, which has no basis in either reality or fantasy and transmits no useful information whatsoever.
A witty [sig] proves nothing. --Voltaire
Geez, don't be so cynical. After I got my PhD from Berkeley, with a dissertation in quantum mechanics, I taught the stuff to graduate students for five years or so. I've published QM papers in PRA and all that, too. So, yeah, I know what they mean. I'm perfectly qualified to review their Nature paper, if it comes to that, and I doubt I'm the only one like this reading /.
I have to say I'm not especially impressed by the work, however. The frisson of defining information as negative emerges ultimately from a semi-deliberate muddling of the distinction between the definition of information in the quantum computing context and information as we use the word in daily life. This is not hard useful scientific discovery so much as the scientific equivalent of making an outrageous pun.
But then I feel similarly about most of what's published in the Bell's Inequality, EPR paradox, quantum tele-whatever field. Getting cynical myself, maybe I am....bah, humbug...grumble...
The trick is that you can use quantum entanglement to have excess unspecified knowledge, which can be converted into specific knowledge. It's like being on a quiz show where you are given a certain number of times you can look up an answer. These bonuses have to count in your total knowledge (I know 100 facts, plus I can look up things twice). If someone tells you something, you get positive information. If you look something up, you get zero information (you trade a bonus lookup for a fact). If you look something up, and you already knew the answer, you get negative information.
Now think about it as if someone else controlled the book. They can tell you things over the phone, and they can cause answers to pop out of the book. If they waste the book on something you actually already knew, your total information goes down, so the information in the transaction is negative.