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Scientists Teleport Information Between Ions a Meter Apart
erickhill writes with word that scientists from the University of Maryland have successfully transferred information from one charged atom to another without having it cross the intervening space of about one meter. The academic paper is available in the journal Science, though it requires a subscription to see more than the abstract.
Scientists have previously teleported unmolested qubits between photons of light, and between photons and clouds of atoms. But researchers have long sought to teleport qubits between distant atoms. Light's high speed of travel makes photons good transporters of information, but for storing quantum information, atoms are a much better choice because they're easier to hold on to. 'This is a big deal,' comments Myungshik Kim, a quantum physicist at Queen's University Belfast in the United Kingdom. 'To store information as it is in quantum form, you have to have a teleportation scheme available between two stationary qubits. Then you can store them and manipulate them later on.'"
I don't think that is how it works (although IANAP)
If you check to see if a block you have is collapsed, then suddenly it becomes collapsed, even if it wasn't before. That means you can't tell what it was supposed to look like before.
The other option is to only look at the entangled matter after you are sure it has collapsed, and see how the collapsing happened. However, this is also impossible. The way the qbits collapse is completely random, so you can't get any useful information out of reading them.
The best way to think about it is you have two coins taped to each other head to tail or something.
Then the coins are flipped, and separated without looking at them. Then take these coins to opposite ends of the universe.
Now, as soon as one coin is observed, the value of the other coin is known as well. However, looking at either coin does not help to relay information. The only way to do that would be to know how the coin was going to land before looking at it. Or to be able to somehow observe the coin and know if the other has been observed.
The way I understand it:
* you generate two entangled quantum things
* you move them apart
* you look at one of them and figure out its state, by that you knock it out of the superposition
* magic happens and the (inverse of that) state is transported to the other thing
* you look at the other thing an confirm that the state is as expected
Since the stuff is in superposition you shouldn't be able to tell its state beforehand, but due to looking at the other thing an teleportation you can. The other thing has the inverse state thing since they must obey conservation of angular momentum (i.e. one spins up, then the other spins down).
Now what I don't get is why this involves any 'teleportation' or quantum weirdness at all. Analog experiment:
* you have two boxes
* you put into one of those boxes a ball at random
* you move them apart
* you look into your box and can now tell if a ball is in the other box or not
* no magic necessary, no teleportation happens, since the state of both boxes is fixed from the start
I don't get why this teleportation thing is anything special, since as far as I understand it, its completly normal and matches exactly what you would expect.