Boffins bounce photons off satellite

Quantum communications offers near-total security

Iain Thomson, vnunet.com 18 Mar 2008

Scientists have successfully hit a satellite with a stream of protons in an experiment to build a global quantum-encrypted communications network.

Professor Anton Zeilinger and his team from the University of Vienna used a 1.5 metre telescope at the Matera Laser Ranging Observatory in Italy to bounce single photons off the Ajisai geodetic satellite 1400km above the earth. The project smashed his previous record of 144km.

With the right satellite in orbit the stream could be used to send quantum-encoded data that is virtually unbreakable using current known technology. But, up until now, the blurring effects of the atmosphere has made sending data in this way practically impossible.

The team managed to hit the Ajisai satellite, which is one of a number of ‘mirror ball’ satellites used solely for measurement, and receive coherent data back. The researchers tried to establish contact with similar satellites further away, but were unable to do so, according to the physics arXiv blog

The next stage would be to build satellites capable of receiving signals and either decoding them and sending back information, or firing them sideways to other satellites to establish a global communications network.

Zeilinger developed the first entanglement-based cryptographic system. He was also the first recipient of the Isaac Newton Medal of the Institute of Physics.

“Zeilinger’s work helped open the way to new quantum information technologies. He developed the first entanglement-based cryptographic system, and more recently worked on implementations of quantum computing using photon cluster states," the Institute of Physics stated.

The professor is also reportedly a huge Douglas Adams fan, so much so that his boat is named 42.

See also: