Added 3 new A* pages:Man, three pages! I was on a roll today, woo.|
There was an interesting Time article yesterday about China having made a breakthrough in cryptology, specifically--according to them--being able to send supposedly unbreakable secret messages over heretofore unmatched distances using a technique called quantum teleportation.
Unfortunately, that's a significant misnomer. You might think at first it's some sort of super-long-range quantum tunneling, but nope, nothing like that at all. It's pretty neat in its own right, though. So basically, if an electromagnetic reaction ends up emitting, for instance, two photons from a single particle, the properties of those photons--energy level and spin, at least, I think--are interdependent, or "entangled." If you have a bunch of those in sequence, you can send one half of the pairs along a laser beam or whatever to your buddies far away. Now, the wacky part is that when the people at one location measure one photon from one of these pairs, that "fixes" its properties--which before that had a range of values due to quantum uncertainty--AND its corresponding photon far away--up to ten miles away, if China's claim is for real--will get fixed, too: it *has* to match the other, in order for conservation of energy to be preserved.
At least, I think that's how it goes, if my skimming of the Wikipedia article wasn't too far off. Pretty amazing to think about. There's a lot more to it after that, because somehow they will still be somewhat different, but if the people at the first site then tell the people at the second site how exactly they altered their photon from the pair, or something, then the people at the second site can perform an operation on *their* photon that will allow them to deduce the value of the first photon. Since nobody else has one of these photons, nobody else can figure out what the value is. So this could be used to send quantum-coded messages to submarines or whatever via laser beams. Or something like that.