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Monday, 17 June, 2002, 07:11 GMT 08:11 UK
Australian teleport breakthrough
Lab, ANU
The research could feed into better telecomunications

It is a long way from Star Trek, but teleportation - the disembodiment of an object in one location and its reconstruction in another - has been successfully carried out in a physics lab in Australia.

Scientists at the Australian National University (ANU) made a beam of light disappear in one place and reappear in another a short distance away.

The achievement confirms that in theory teleportation is possible, at least for sub-atomic particles; whether it can be done for larger systems, such as atoms, remains to be seen.

The more likely applications will come in telecommunications, enabling much faster transfer of data and the use of encryption that can never be broken.

Teleportation has been one of the hottest topics among physicists working in quantum mechanics - the study of the fundamental structure of matter.

Some 40 labs around the world are currently trying to teleport a laser beam after pioneering work in 1998 at the California Institute of Technology showed it should be possible.

'Spooky interaction'

The Australian researchers have exploited a phenomenon called "quantum entanglement", which links the properties of two photons of light created at the same time. Einstein called it a "spooky interaction".

What it means is that two photons can be created and sent to different places. It is possible to force one photon into a specific quantum mechanical state and, because the two photons are connected in some way, the other photon will instantaneously take up a complementary state.

At first sight, entanglement offers the prospect of sending a signal faster than the speed of light. But a closer look at what is actually possible shows that this will not work because of the limits of what can be known about quantum mechanical systems and how such information is relayed.

But it may offer the prospect of a Star Trek-style transporter.

'Exciting applications'

Using quantum entanglement, ANU physicist Ping Koy Lam has disassembled laser light at one end of an optical communications system and recreated a replica just a metre away.

An encoded signal is embedded in an input stream of photons, which is entangled with another beam.

Elsewhere in the lab, the beam of photons and the associated signal is reconstituted.

"What we have demonstrated here is that we can take billions of photons, destroy them simultaneously, and then recreate them in another place," Dr Lam says.

"The applications of teleportation for computers and communications over the next decade are very exciting," he adds.

Body movement

Quantum teleportation could make encrypted or coded information 100% secure, Dr Lam said, because even if intercepted the message would be unintelligible unless it was intended for a specific recipient.

"It should be possible to construct a perfect cryptography system. When two parties want to communicate with one another, we can enable the secrecy of the communication to be absolutely perfect."

But for a human to be teleported, a machine would have to be built that could pinpoint and analyse the trillions and trillions of atoms that make up the human body.

"I think teleporting of that kind is very, very far away," Dr Lam says. "We don't know how to do that with a single atom yet."

Quantum teleporting is problematic for humans because the original is destroyed in the process of creating the replica.

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The BBC's Peter Biles
"It's the stuff of science fiction"
See also:

17 Jun 02 | Science/Nature
20 Jan 00 | Science/Nature
20 Jul 99 | Science/Nature
27 Oct 98 | Science/Nature
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