Quantum entanglement discovery promises to smooth the way to quantum communications

June 22, 2009--A team led by researchers at The Australian National University (ANU; Canberra, Australia) report development of a breakthrough approach to generating quantum entanglement, wherein information is coded in the physical relationship between two objects. The discovery, which has implications for communication and data processing, is based on existing optical technology, but uses it in such a way that many fewer components and light beams are required.

June 22, 2009--A team led by researchers at The Australian National University (ANU; Canberra, Australia) report development of a breakthrough approach to generating quantum entanglement, wherein information is coded in the physical relationship between two objects. Their findings are published in this week's Nature Photonics. The discovery, which has implications for communications and data processing, is based on existing optical technology, but uses it in such a way that many fewer components and light beams are required.

"Until now, the amount of information that could be conveyed using optical entanglement was limited by levels of complexity," said Dr. Jiri Janousek of ANU's ARC Centre of Excellence for Quantum-Atom Optics, who led the research. "The ability to scale up information transfer is hampered by the fact that you need to increase the number of nonclassical light sources, splitters and receivers each time you want to add another channel of information. This means that multi-channelling has been consigned to the 'too-hard' basket--too many parts for too little effect."

Janousek said that the group's discovery about mode manipulation in light meant that only one light source and one receiver is required to generate optical entanglement, meaning that this approach could be much more simply scaled up to convey many times more information channels. "Light beams produced from lasers can be used to convey information via a process known as quantum entanglement," said Janousek. "Basically this means that at the miniscule scale of the quantum world, information about one object--a stream of photons, for example--can convey information about another object to which it is linked. We can use quantum entanglement, or optical entanglement, to convey information."

"There are only ten labs in the world that would be able to do this kind of research, and we were the first to find a solution to this particular problem," Janousek noted. "This finding is one more piece in the puzzle towards the future realization of quantum computers, which would be many times faster and more powerful than existing computers. But in the medium timeframe this discovery could assist in the development of quantum technologies--things like quantum communication and information processing."

In addition to scientists from ANU, the research team included Laboratoire Kastler Brossel in Paris and the Australian Defence Force Academy. The project was funded by the Australian Research Council, with support from ANU, CNRS the Ecole Normale Superieur, and the European Commission's Seventh Framework Programme for Research.

For more information, see the paper, Optical entanglement of co-propagating modes, in Nature Photonics.

See also the site for ANU's ARC Centre of Excellence for Quantum-Atom Optics.

Posted by Barbara G. Goode, barbarag@pennwell.com, for Laser Focus World.

More in Research