Open-Destination Quantum Teleportation

Roland Piquepaille writes "An international team of physicists has entangled five photons for the first time in the world, reports Technology Research News in "Five photons linked." Why is this important? Because it's the minimum number of qubits needed for universal error correction in quantum computing. In other words, they found a way to check computational errors in future quantum computers. The physicists also demonstrated what they call 'open-destination teleportation,' a way to teleport quantum information within and between computers." "They teleported the unknown quantum state of a single photon onto a superposition of three photons. They were then able to read out this teleported state at any one of the three photons by performing a measurement on the other two photons," adds PhysicsWeb in "Entanglement breaks new record ". This will be used in about ten to twenty years to move information among quantum networks. You'll find more details and references in this overview."

Comments

Re:oh please

[Klar]

This could lead to downloading mp3's before they have been recorded.. try to stop that RIAA bastards!

Future or syntax?

[sammyo]

"they found a way to check computational errors in future quantum computers."

Just how far in the future will we be able to check? Should be a great aid to debugging! But what happens if I fix a problem that causes my great grandson to come back in time to help me to meet my wife? Oh, wait.

Quantum Teleportation explained.

[Aaron England]

Teleportation is the name given by science fiction writers to the feat of making an object or person disintegrate in one place while a perfect replica appears somewhere else. How this is accomplished is usually not explained in detail, but the general idea seems to be that the original object is scanned in such a way as to extract all the information from it, then this information is transmitted to the receiving location and used to construct the replica, not necessarily from the actual material of the original, but perhaps from atoms of the same kinds, arranged in exactly the same pattern as the original. A teleportation machine would be like a fax machine, except that it would work on 3-dimensional objects as well as documents, it would produce an exact copy rather than an approximate facsimile, and it would destroy the original in the process of scanning it. A few science fiction writers consider teleporters that preserve the original, and the plot gets complicated when the original and teleported versions of the same person meet; but the more common kind of teleporter destroys the original, functioning as a super transportation device, not as a perfect replicator of souls and bodies.

In 1993 an international group of six scientists, including IBM Fellow Charles H. Bennett, confirmed the intuitions of the majority of science fiction writers by showing that perfect teleportation is indeed possible in principle, but only if the original is destroyed. In subsequent years, other scientists have demonstrated teleportation experimentally in a variety of systems, including single photons, coherent light fields, nuclear spins, and trapped ions. Teleportation promises to be quite useful as an information processing primitive, facilitating long range quantum communication (perhaps unltimately leading to a "quantum internet"), and making it much easier to build a working quantum computer. But science fiction fans will be disappointed to learn that no one expects to be able to teleport people or other macroscopic objects in the foreseeable future, for a variety of engineering reasons, even though it would not violate any fundamental law to do so.

In the past, the idea of teleportation was not taken very seriously by scientists, because it was thought to violate the uncertainty principle of quantum mechanics, which forbids any measuring or scanning process from extracting all the information in an atom or other object. According to the uncertainty principle, the more accurately an object is scanned, the more it is disturbed by the scanning process, until one reaches a point where the object's original state has been completely disrupted, still without having extracted enough information to make a perfect replica. This sounds like a solid argument against teleportation: if one cannot extract enough information from an object to make a perfect copy, it would seem that a perfect copy cannot be made. But the six scientists found a way to make an end run around this logic, using a celebrated and paradoxical feature of quantum mechanics known as the Einstein-Podolsky-Rosen effect.

Read just how this effect works, here.

This is first

[JustOK]

Thanks to quantum computation and teleportation, this is actually the first post.

I don't think three is enough...

[eRacer1]

On my systems three Q*berts is not sufficient for error correction in my simulations. Coily always gets me sooner rather than later.

Re:This is what a normal person just read above.

[Dorothy 86]

It also means one step closer to computers powerful enough that we can, say for example, model the human body to test all possible drug combinations at the same time.

you forgot that it is one step closer to being able to run Longhorn!

Re:This is what a normal person just read above.

[zangdesign]

One step closer to the singularity...

The day some idiot turns decision making over to computers is the day I start the Butlerian Jihad.

Re:This is what a normal person just read above.

[krumms]

It's actually fairly simple. In QC, you can perform any quantum operations on the qubits, but you cannot look at the bits without losing some information. Therefore, what you do is use error correcting codes, by superimposing the quantum states onto a set of photons whose states you observe, but do not use. What they have done here is basically taken the unknown quantum state of a photon onto a superposition set of three photons, and you can find the state of any one photon by observing the other two photons.

Ah, much better. Thank you for putting it in layman's terms.

Now, if you'll excuse me I think I feel my head exploding ...