The traveler would be scanned to create the entangled pairs (top beam). Unfortunately, he would be destroyed in the process.
BY JIM WILSON Illustrations by Jeff Mangiat
This time last year the idea of teleporting matter existed only in science fiction and the dense equations of quantum theory. As a result of experiments conducted in Europe since then, the notion that matter can be moved from here to there without being anywhere in between has achieved new respectability.
Understand that a teleportation system won't work anything at all like the transporter that Captain Kirk used to beam down to class M planets. That fictional machine "beamed" the body mass of crew members into space as energy. The type of teleportation system being discussed by scientists such as Charles H. Bennett–a physicist at the IBM T.J. Watson Research Center in Yorktown Heights, N.Y., who conceived of the current approach–would send only information about the atoms that compose the traveler. At the destination this information would then be used to assemble a copy of the traveler from local materials.
This may seem as preposterous as Scotty managing to keep his accent after a lifetime spent working with people who talk like they're from Jersey, save one fact: Researchers have already proved it is possible to "teleport" this sort of quantum information about a photon, or packet of light. The Austrian and Italian teams that did this work are now designing experiments that would enable them to teleport an electron.
Electrons–the lightweight, negatively charged particles that orbit the nuclei of atoms–are responsible for most everything we see around us. Not the least of which are our bodies. Electrons perform many functions, including coupling atoms together to form molecules.
One of the most important characteristics of an electron is a property called spin. As the diagram on the opposite page shows, an electron can have either a clockwise or counterclockwise spin relative to a magnetic field. Physicists describe the spin as being "up" or "down." Under certain circumstances electrons created at the same moment can enter into what is called an "entangled state." From that time forward, they remain linked even though they are physically separated.
It's like this: Imagine for a moment that you take a pair of coins from your pocket and give one to a friend, who travels to, say, Hong Kong. When your friend arrives he calls you on the phone and the two of you start flipping your coins simultaneously. Now imagine that for some reason every time your coin lands heads-up, his coin lands heads-down. And every time your coin lands tails-up, his coin lands tails-down. Impossible, right?
Yet that's the way it works in the subatomic realm. Just substitute entangled electrons for coins, and spin for heads and tails. The rules of quantum theory require that if the spin on one entangled electron is up, the spin of the other must be down. Even if the two electrons are a thousand–or 10 million–miles apart.
Hang on, things are about to get stranger. Before a real coin hits the ground it has an equal chance of landing heads or tails. However, the rules of quantum theory require electrons in an entangled state each to have spin that is both up and down.
In superposition of two electrons, spin is both up and down.
Their spins don't become fixed until the electrons are "observed" see "Executing Schrödinger's Cat," Oct. 1997. Bennett believes a particle's ability to exist in this "superposition" holds the key to building a real teleporter.
Stripped to its basics, a teleporter would work something like this: An object is scanned atom by atom. This process breaks up the atom to create entangled pairs of particles. The entangled pairs are stretched so that the superposition extends between the transmitting and receiving points. At the receiving end, the information contained in the "superposition" of entangled particles is used to duplicate the original quantum conditions–in atoms drawn from the immediate surroundings. You disintegrate at one end and pop out at your destination, literally a new person.
Don't cancel your frequent flyer programs just yet. The process needs to be scaled up a bit first. For their next step, teams at the University of Innsbruck in Austria and the University of Rome are preparing to teleport an electron. A whole atom and molecule come next. Within a decade, Anton Zeilinger of the Austrian team believes it will be possible to teleport a small virus.
Teleporting the flu may seem a dubious enterprise. But consider this: If a small package of genetic material could be teleported, why couldn't the genome containing the blueprint for the human body?