Scientists Find Method To Reliably Teleport Data

An anonymous reader writes "Scientists at the Kavli Institute of Nanoscience say they've managed to reliably teleport quantum information stored in one bit of diamond to another sitting three meters away (abstract, pre-print) . Now, their goal is to extend the range over a distance of a kilometer. '[R]eliability of quantum teleportation has been elusive. For example, in 2009, University of Maryland physicists demonstrated the transfer of quantum information, but only one of every 100 million attempts succeeded, meaning that transferring a single bit of quantum information required roughly 10 minutes. In contrast, the scientists at Delft have achieved the ability "deterministically," meaning they can now teleport the quantum state of two entangled electrons accurately 100 percent of the time. They did so by producing qubits using electrons trapped in diamonds at extremely low temperatures. According to Dr. Hanson, the diamonds effectively create 'miniprisons' in which the electrons were held. The researchers were able to establish a spin, or value, for electrons, and then read the value reliably.'"

Re:This research should receive enormous funding.

[TeknoHog]

You can't use quantum teleportation to transmit information faster than light. QT requires a classical information channel (like fiber optic cables) on the side to actually work. The point about QT is being able to transfer a quantum mechanical state, i.e. the wavefunction with its full phase information. You cannot do that with classical means, because you'd need to measure the state, thereby collapsing it into a classical state.

Re:This research should receive enormous funding.

[barlevg]

I realize you were making a joke based on a perception common in popular culture, but the truth is that the Schrodinger's Cat paradox has a simple resolution: the cat *cannot* be both alive and dead because the detector (which detects whether the decay has occurred and which triggers the release of the poison if the decay occurred) collapses the wave function of the particle. There's no such thing as a passive detector. So while a subatomic particle could indeed exist in a superposition of "decayed" vs. "not decayed," the second you go about asking the particle whether it's decayed (that is, when you set up the detector), the wave function collapses, and no superposition is possible.

Re:This research should receive enormous funding.

[NotDrWho]

Anyone remember the movie "Mystery Men"? One of the characters in that movie summed up my feelings on modern quantum physics pretty nicely. He was "Invisible Boy." But he could only become invisible when no one was looking (not even himself), and no cameras were on him. The second that anything that could actually verify his ability tried to do so, he became visible again. This led to the obvious question "How do you know you have this power at all?" to which he relied "Well, I just feel it."

Re:This research should receive enormous funding.

[barlevg]

Basically, we know that superpositions exist because we can perform experiments in which, if a particle were always in one state or the other, the results would be different. See: double-slit experiment [wikipedia.org]. If photons didn't exist in a superposition of states, then the distribution of light you'd get with the double slit would be the distribution you get from having one slit covered plus the one you'd get from covering the other one. But you don't--the distribution is completely different, which means that a single photon somehow travel though *both* slits and "interferes with itself." It's more than a little batshit.

Re:This research should receive enormous funding.

[Charliemopps]

I realize you were making a joke based on a perception common in popular culture, but the truth is that the Schrodinger's Cat paradox has a simple resolution: the cat *cannot* be both alive and dead because the detector (which detects whether the decay has occurred and which triggers the release of the poison if the decay occurred) collapses the wave function of the particle. There's no such thing as a passive detector. So while a subatomic particle could indeed exist in a superposition of "decayed" vs. "not decayed," the second you go about asking the particle whether it's decayed (that is, when you set up the detector), the wave function collapses, and no superposition is possible.

You're presenting your interpretation as fact, and it's not. It's a possible scenario, but this thought experiment is designed explicitly to show a paradox that we have yet to resolve. What you describe is the "Copenhagen interpretation" which was proposed by Niels Bohr, Werner Heisenberg and others in 1924 to 1927. It states that quantum states are not fixed but probabilities. Just as you said, once any measurement is made the wave function collapses and the state is fixed in the classical sense. If this interpretation is true, then you are correct. But there are many other interpretations that have any equally valid chance of being correct.

In the "Many-Worlds" interpretation, the cat really is both alive and dead. When you open the box you become entangled with the cat (not literally, that would hurt) and one version of you perceives it as alive and another perceives it as dead. Both results occur, you experience both, but you remain unaware of your duplicate and he of you.

Einstein himself supported an entirely different interpretation called the "Ensemble interpretation" which basically just makes the entire thought experiment irrelevant. It's wacky and hard to explain so I'll just link to it: http://en.wikipedia.org/wiki/E... [wikipedia.org]

Anyways, I recommend reading up on Schrödinger's cat via Wikipedia or some other source. You're only incorrect in that you thought your explanation was the only one.

Oh, and full disclosure, I'm not a scientist, I just find this stuff incredibly interesting. Also it makes me sound smart at parties. Actually I don't get invited to parties... they say I ramble on about nonsense. Thank God for the many worlds theory... at least I'm popular somewhere.

Re:Ignore previous reply

[Anonymous Coward]

But a Gieger counter sitting on some table is well coupled to the lab and environment around it and would allow for coherence as with any other interaction outside the closed system under consideration. If you could construct a way of isolating a cat from the environment, you could use the same method on a gieger counter, and then the effects of "unconscious observation" would go away in a closed system. Things like this have been tested on a smaller scale using detection methods that can be isolated or not, and in the isolated cases superposition returns.

Re:If information can't be sent faster than C.....

[Zalbik]

IANAP (I Am Not A Physicist), but as I understand it, the information is sent instantaneously (teleported), but can only be "read" via the use of a measurement taken at the source location & sent (via classical channels) to the target.

i.e.:
2 entangled particles exist. One at A and one at B
Measurement is take an A. This results in a change of state to both particles
Unfortunately, due to quantum funkiness, the state at B cannot be determined without the measurement from A.
Measurement is sent from A to B (via classical channels)
B can then determine the state of their particle (which matches the state at A)

Please excuse any butchering of the science that may of occurred due to my ignorance :-)