How it's possible to know less than zero
From: John Raines
I was reading Slashdot this evening and came across something that is strongly reminiscent of the famous "Dave" letter about electric trailer brakes, etc.
The item was titled "Quantum Information Can Be Negative," and proceeds:
"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 information 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.org for those of us without subscriptions to Nature.