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Quantum computing taps nucleus of single atom

A team of Australian engineers at the University of New South Wales (UNSW) has demonstrated a quantum bit based on the nucleus of a single atom in silicon, promising dramatic improvements for data processing in ultra-powerful quantum computers of the future.

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Quantum bits, or qubits, are the building blocks of quantum computers, which will offer enormous advantages for searching expansive databases, cracking modern encryption, and modelling atomic-scale systems such as biological molecules and drugs. When coupled together these qubits will give rise to exponential increases in computing speeds.

The world-first result, published in Nature, brings these machines one-step closer, describing how information was stored and retrieved using the magnetic spin of a nucleus.

“We have adapted magnetic resonance technology, commonly known for its application in chemical analysis and MRI scans, to control and read-out the nuclear spin of a single atom in real time,” says Associate Professor Andrea Morello from the School of Electrical Engineering and Telecommunications (EE&T) at UNSW.

The nucleus of a phosphorus atom is an extremely weak magnet, which can point along two natural directions, either “up” or “down”. In the strange quantum world, the magnet can exist in both states simultaneously – a feature known as quantum superposition.

The natural positions are equivalent to the “zero” and “one” of a binary code, as used in existing classical computers. In this experiment, the researchers controlled the direction of the nucleus, in effect “writing” a value onto its spin, and then “reading” the value out –...

The full text of this article can be purchased from Informit.