In science fiction, teleportation entails taking someone and creating a replica of him or her a long distance away, and destroying the original. It remained confined to pulp literature until a decade ago. The perceived barrier to it was something called the Heisenberg Uncertainty Principle. This principle states that the more accurately you try to scan or measure an atom or other object in order to teleport it, the more you disrupt its original quantum state, and so you cannot create a true replica.
Things changed in 1993 with a landmark paper by a team led by an IBM scientist, Charles Bennett, who thought up a way of getting around this problem using photons, or particles of light, as the object to be transported.
Their answer was to exploit something called "quantum entanglement," in which a laser beam is squeezed and split in such a way that it creates two particles of light at the same time.
Particles created in this exotic process behave like psychic twins. Even if they are far apart, a disturbance to one particle affects the other, a phenomenon once dubbed "spooky interaction" by Einstein.
Their idea was to use these "entangled" particles as transporters. By introducing a third "message" particle into the light stream, one could transfer its properties to both sets of particles.
It would work like this: One of the "twin" beams is scanned, which in the process destroys its quantum state. The information is sent to the recipient via a classical communications channel, and is transformed back into a light beam. The recipient then combines this light beam with the second entangled beam he has received, and in so doing "unwraps" the original message in its virgin state.
The first concrete results from this idea began emerging in 1997, with a couple of labs in Europe and the United States transporting a small unit of information, called a quantum bit (qubit), a distance of about one meter (3.25 feet).
But, in a study reported Thursday in the British weekly journal Nature, scientists at the University of Geneva, Switzerland, and the University of Aarhus, Denmark, have teleported data to another lab 55 meters (178 feet) away through a 2-kilometer (1.25-mile) roll of standard fibre-optic cable.
Kirk, Scotty and Bones still remain in the distant, sci-fi distance, however.
In spite of the breakthrough, teleportation is still restricted to light particles. No-one is even close to teleporting an atom or a bacteria, even less a human being.
Where there could be an early use is in secret communications — creating encrypted messages, each of which would have a unique, unbreakable key and whose interception would be a obvious giveaway to the recipient.
"The first (and, with foreseeable technologies, the only) application of quantum teleportation is in quantum communication, where it could help extend quantum cryptography to larger distances," the authors, led by Geneva University's Nicolas Gisin, said.
