Beam me up my cup of coffee, Scotty

So you think zapping things across the universe in a teleporter is just sci-fi nonsense? Well hold on to your phaser, Captain Kirk: it could just happen
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The Independent Online

There is a true story of a man standing in the dock of a court who has just been found guilty of a whole series of fairly serious crimes. "Is there anything you would like to say before I pass sentence?" asks the judge, hoping to extract some remorse. "Yes," says the defendant flipping open his wallet and putting it to his mouth. "Beam me up, Scotty."

Sadly for the defendant, being teleported from the dock was just as likely as the judge appreciating the joke (the crook, incidentally, went down for longer than he otherwise would). Ever since the early years of Star Trek, teleportation - the instantaneous movement of a person from one place to another - has been little more than a dream. Imagine walking into a cylindrical booth at the end of your street in Dudley and ending up a few seconds later in the brilliant sunshine of Bondi Beach. What may be a routine transport system in the fantasy world of Captain Kirk seems just too implausible to ever come true.

But listen up, the word is out that teleportation is for real. At least three groups of serious scientists are working on it. They all claim to have achieved a form of limited teleportation. Nobody is suggesting a Global Teleportation Authority within 10 years - or even 100 years - but the research at least holds out the hope that one day we might be able to walk into that glass cylinder on the street corner and come out just about anywhere in the world we choose.

They call it "quantum teleportation" because it involves the branch of physics that treats everything as bundles of particles, or quanta. Break something down to its constituent parts, describe every facet of each and every particle, send this information to a distant place, and reconfigure every conceivable part of the original object. Hey presto, just like magic, you have quantum-teleported something from one place to another.

For most of us, it might just as well be magic. To say that quantum physics is the most esoteric of subjects is an understatement. Even scientists who have won Nobel prizes for their contributions to quantum theory have admitted they do not really understand it. Yet "quantum this" and "quantum that" are going to be the buzz phrases of the 21st century, if you believe Michael Crichton, the Jurassic Park author who knows something about predicting the scientific zeitgeist. His latest work, Timeline (Century, £16.99) is all about the apparent magic of quantum theory, and how it can be used to teleport people through time as well as space, with the help of the odd "quantum wormhole".

Crichton paints a picture of quantum teleportation that is self-evidently fiction. But he cleverly interleaves his more outlandishly imaginative ideas with some real science, making quantum transport seem more plausible than it actually is. Through one of his characters in Timeline, Crichton describes the strange nature of quantum particles and the even stranger phenomenon of how they can interact with each other over vast distances.

"You can't be sure where they are, you can't measure them exactly, and you can't predict what they will do," Crichton writes. "Sometimes two particles will interact with each other even though they're a million miles apart, with no connection between them. And so on. The theory is starting to seem extremely weird."

The idea of particles interacting over vast distances - called entanglement - is the fundamental basis for believing that teleportation may be possible. It all began exactly 100 years ago when Max Planck, a German physicist, first formulated quantum theory. It was quickly picked up by Albert Einstein, who argued that energy waves could be described as discrete packets, or quanta. Light waves, for instance, were actually made up of individual particles called photons.

Einstein, the man often described as the brightest spark of the last millennium, juggled expertly with the mind-bogglingly weird concepts of space and time, but there was one facet to quantum theory that even he was freaked out about - interacting particles. He was so freaked out, in fact, that he called the idea "spooky".

Dabbling with the intricate details of quantum theory, Einstein realised that it was theoretically possible for two distinct particles to be so intimately connected by a "quantum bridge" that one could influence the other no matter how far apart the two of them are. Change the properties of one, and the other gets changed automatically, even if it is on the other side of the universe. The supernatural, almost telepathic nature of "entanglement" spooked Einstein so much he broke out into a cold sweat at the very thought.

Yet events over the past 10 years have shown that entanglement is more that just a theory. In a groundbreaking piece of research published in 1993, a team of scientists led by Charles Bennett of IBM's research division in Yorktown Heights, New York, showed that entanglement was a practical possibility, a way of overcoming one of the principle stumbling blocks of teleportation - Heisenberg's uncertainty principle, which states that it is impossible to know the precise quantum state of every particle at any one time.

The uncertainty principle meant that it would be impossible to know enough about each particle of an object to teleport this information to another place in the hope of recreating that object exactly. However, entanglement meant that you did not need to know this information because what is important is that whatever you did to one particle, another particle elsewhere would suffer exactly the same fate.

"In an entangled state, distant particles are linked in a way that they classically couldn't be unless they were in the same place," explains Bennett. What he described in 1993 was a theoretical framework which could, in principle, lead to someone being able to "fax" a cup of coffee from London to San Francisco.

The 1993 breakthrough quickly moved from theory to practice. In 1997, Anton Zeilinger and colleagues at the University of Vienna succeeded in performing the first rudimentary teleportation experiment. They used the notion of quantum entanglement to move a single light particle from one place to another. It may not not have impressed Scotty, but it was a start.

The technique has since been refined still further by other scientists, notably Jeff Kimble at the California Institute of Technology and Samuel Braunstein at the University of Wales in Bangor. They claimed the first "true" teleportation of a photon in 1998 when they succeeded it moving it across a laboratory bench "without it traversing any physical medium in between", they said at the time. Weird indeed.

"In our case the distance was only a metre, but the scheme would work just as well over much larger distances," Professor Braunstein says. "It's exceedingly early days and asking whether it could ever be practical to transport people is like asking the first person who used an abacus whether they could dream of the day when computers could be used in medicine," he says.

Jeff Kimble says quantum teleportation is far more likely to be used as a way of setting up a new kind of hyper-intelligent internet which uses quantum theory to "teleport" information around the globe. Scientists are already working on quantum computers, which will replace the conventional silicon chip with atomic-sized electrical switches based on the quantum states of particles. In 20 years, advances in silicon chips are expected to come to the end of their technical ability, and quantum computing is set to take over.

As regards the more exciting possibility of devel- oping "quan- tum people carriers", Kimble is rather more phlegmatic. "I don't think that we know enough at the moment to even ask the question, let alone answer it. The poss-ibilities at the moment range from 'yes it may be possible at some distant point in future', to 'no, not a chance'," Kimble says.

Sadly, that dream of being able to teleport oneself to Bondi Beach must remain just that - for now at least.