An international team of researchers from the University of Surrey, UCL, Heriot-Watt University and the FOM Institute for Plasma Physics have used infra-red laser to obtain precise control of the quantum superpositions of an electron in silicon for the first time. This feat marks yet another leap toward the dream of an affordable, fast and reliable quantum computer.
Close to reaching the insurmountable performance wall of conventional electronics, researchers have long been working on a completely different approach to information processing. Should this technology be perfected within the next 15 to 20 years as is expected, quantum computing would not only allow us to reach miniaturizations far beyond the predictions of Moore's law, but would also allow us to solve existing problems with significantly less operations, as we;; as problems – particularly in the security area – that computers using the traditional approach are unable to even formulate.
In the quantum computing world, superposition is the ability of a "quantum bit" to assume two or more values at the same time; while counterintuitive, this property forms the basis for the unique and extraordinarily efficient approach of this emerging technology. Precise control of superpositions has been achieved before, as was a rudimental all-electronic quantum processor, but this piece of research marks the very first time that superpositions are being controlled in silicon, which paves the way to significantly cheaper quantum computers.
The team used an infrared, high-energy laser pulse to put a phosphorus electron orbiting within silicon into two states at once, and then went on to show that the electrons emit a burst of light at a well-defined time after the superposition was created, proving the full control over the quantum state of the atoms.
"This is a real breakthrough for modern electronics and has huge potential for the future," explained Prof. Ben Murdin, who was part of the research team. "Lasers have had an ever increasing impact on technology, especially for the transmission of processed information between computers, and this development illustrates their potential power for processing information inside the computer itself."
A Paper detailing the team's finding is available from the online edition of the journal Nature.