Photons teleported over 60 miles

Posted by Emma Woollacott

Chinese scientists have smashed the distance record for quantum teleportation, zapping entangled photons over 60 miles.

The big breakthrough comes courtesy of a new steering mechanism that uses a guide laser to keep the photon beam on target. Previous efforts have had to deal with beams that widened and attenuated over greater distances.

The physicists, working from the University of Science and Technology of China in Shanghai, have broken their own previous record, set two years ago.

With quantum teleportation, it's not the object itself that is transmitted - rather, the information that defines it. The 'identity' of the original photon is essentially transferred to a new one. Because the information is transferred instantly, rather than traveling between the two photons, it should be impossible to intercept.

The Chinese team says it's been able to teleport more than 1,100 photons in four hours over a distance of 97 kilometres. And this, as MIT points out, brings channel attenuation down to a level that could make the technique viable for beaming photons to a satellite.
http://www.technologyreview.com/blog/arxiv/27843/?ref=rss

This would open up the opportunity for satellite-based quantum cryptography, allowing secure messages to be sent and received anywhere in the world.

"Besides being of fundamental interest, our result represents an important step towards a global quantum network," say the authors.

"Moreover, the high-frequency and high-accuracy acquiring, pointing and tracking (APT) technique developed in our experiment can be directly utilized for future satellite-based quantum communication."