04 March 2010
Quantum computing comes closer
Researchers at the Ruhr University in Bochum and the Universities of Stuttgart and Austin have managed to place two nitrogen atoms a few nanometers apart within a diamond lattice; close enough that laser excitation can create quantum mechanical coupling.
"Initially, numerous groups focused on silicon," says Dr Jan Meijer at Bochum's Rubion research institute. "But this research has demonstrated that diamonds are particularly well suited for coupled quantum circuits."
The research confirms a hypothesis put forward some years ago by Stuttgart scientists Prof Dr Jörg Wrachtrup and Dr Fedor Jelezk. They claimed NV centres – where N stands for nitrogen and V for a vacancy –would be immobile in a surrounding carbon lattice. Since there is no diffusion inside a diamond, the atoms won't migrate. When targeted by a laser, the two nitrogen centers will react and a manipulable superposition of their spin states – the rotational movement of electrons – results
The coupling of the atoms in the diamond is said to work at room temperature: the crucial requisite for building quantum computers. Meijer added: "Basically, it is possible to create several of these NV centres by means of ion implantation, couple them together in a scalable fashion and have a classical computer control it all."
The next challenge for the researchers is to increase the number of couplings. "This is a great challenge," says Meijer, "because the greater the number of couplings, the faster the system will fall apart."
Author
Graham Pitcher
Supporting Information
Websites
http://www.rub.de
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