Technology: Quantum teleportation achieved over long distance

If teleportation of Star Trek was just science fiction, it seems that the progress of science shows us otherwise. Quantum teleportation has achieved a new milestone or, should we say, a new "ten-milestone": scientists have recently had success teleporting information between photons over a free space distance of nearly ten miles using quantum teleportation technology.

"Quantum teleportation" is quite different from how many people imagine teleportation to work. Rather than picking one thing up and placing it somewhere else, quantum teleportation involves entangling two things, like photons or ions, so their states are dependent on one another and each can be affected by the measurement of the other's state.

Teleportation over distances of a few hundred meters has previously only been accomplished with the photons traveling in fiber channels to help preserve their state. In this particular experiment, researchers maximally entangled two photons using both spatial and polarization modes and sent the one with higher energy through a ten-mile-long free space channel. They found that the distant photon was still able to respond to changes in state of the photon they held onto even at this unprecedented distance.

The fundamental advantage of quantum information systems is that whereas a conventional digital bit can be 0 or 1, a qubit can be in a so-called superposition of 0 and 1 simultaneously.

The team, led by physics graduate student Steven Olmschenk at the University of Maryland, College Park, succeeded in teleporting quantum information between ytterbium ions (charged atoms).

Paul Kwiat, a physics professor at the University of Illinois at Urbana–Champaign, says that distant teleportation between potential qubits of quantum memory is a definite milestone. "The whole point of teleportation is getting the information far away," Kwiat says, noting that in prior micron-scale teleportation demonstrations with matter qubits, the researchers might have been better off simply moving the qubits physically from point to point. (A micron is one millionth of a meter, or about one twenty-five-thousandth of an inch.)

The ability to transmit information between bits of quantum memory could form the basis of so-called quantum repeaters, point-to-point networks that relay data down the line. "The idea is to in some sense boost the information along the way—to send it a short distance and then have it in some sense be amplified and sent on again and again to complete a transfer over a long distance" said Olmschenk.

Soon, the commands we used to hear from captain Picard of the Enterprise space ship "Energize!" and "Engage!" may become a reality sooner than we thought!