Physicists Teleport Quantum Bits Over Long Distance

By John Roach
for National Geographic News
January 29, 2003

Fans of the television and movie series Star Trek often lust after the technology that allows characters to step onto a transporter and be instantaneously whisked from one room on the U.S.S. Enterprise to another room, another planet, or another universe.

The technology is known as teleportation. It involves taking away the material properties of an object at one location and transferring the exact details of its configuration to another location where it is reconstructed.

Today, scientists debate whether human teleportation as depicted by the Star Trek series is theoretically possible or even desirable, but over the last decade they have made great strides in the field of quantum teleportation.

Quantum teleportation is the transferring of tiny units of computer information, called quantum bits or qubits, from one location to another. The technology is referred to as a type of teleportation because the information teleported behaves more like an object than normal information.

"It is quantum information, which cannot be copied and cannot appear at the new location without being destroyed at the old location," said William Wootters, a physicist at Williams College in Williamstown, Massachusetts who co-authored a 1993 paper that outlined the theory of quantum teleportation.

Scientists treat quantum information as if it were an object. The fact that the information cannot be conveyed without first being destroyed also differentiates quantum teleportation from faxing a document, which makes an imprecise replica of the original at another location and leaves the original intact.

Since Wootters and colleagues published their paper in 1993, scientists have worked to prove the theory correct. The most recent success is reported by a team of physicists from the University of Geneva in Switzerland in the January 30 issue of Nature.

"We report the first experimental long distance demonstration of this fascinating aspect of quantum mechanics," said Nicolas Gisin, a physicist at the University of Geneva.

His team teleported qubits carried by photons—particles of light—of 0.05 inch (1.3mm) wavelength in one laboratory onto photons of 0.06 inch (1.55mm) wavelength in another laboratory 180 feet (55 meters) away along 1.2 miles (2 kilometers) of fiber optic wire.

In 1997 and again in 1998, scientists successfully demonstrated the concept of quantum teleportation by transferring two dimensional systems over short distances, such as from one side of a table to the next. Gisin and his team prove that the concept of quantum teleportation holds up at longer distances.

"Gisin's work sounds like a significant achievement," said Samuel Braunstein, a professor of informatics at the University of Wales in Bangor, England who was part of a team that teleported photons from one end of a table to the next in 1998.

Continued on Next Page >>


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