News

Computing with a single atom

18/09/2012

University: UNSW Sydney

Authors Centre Participants: Prof. Andrea Morello, Prof. Andrew S. Dzurak, Prof. David N. Jamieson, Prof. Michelle Y. Simmons AO, Prof. Sven Rogge

Other Source: UNSW newsroom

A research team led by Australian engineers has created the first working quantum bit based on a single atom in silicon, opening the way to ultra-powerful quantum computers of the future. Their work was published online by Nature on Thursday 20 September.

Quantum vision: Computing with a single electron in silicon

A research team led by Australian engineers has created the first working quantum bit based on a single atom in silicon, opening the way to ultra-powerful quantum computers of the future.

In a landmark paper published today in the journal Nature, the team describes how it was able to both read and write information using the spin, or magnetic orientation, of an electron bound to a single phosphorus atom embedded in a silicon chip.

“For the first time, we have demonstrated the ability to represent and manipulate data on the spin to form a quantum bit, or ‘qubit’, the basic unit of data for a quantum computer,” says Scientia Professor Andrew Dzurak. “This really is the key advance towards realising a silicon quantum computer based on single atoms.”
Dr Andrea Morello and Professor Dzurak from the UNSW School of Electrical Engineering and Telecommunications lead the team. It includes researchers from the University of Melbourne and University College, London.

“This is a remarkable scientific achievement – governing nature at its most fundamental level – and has profound implications for quantum computing,” says Dzurak.

Dr Morello says that quantum computers promise to solve complex problems that are currently impossible on even the world’s largest supercomputers: “These include data-intensive problems, such as cracking modern encryption codes, searching databases, and modelling biological molecules and drugs.”

The silicon approach: UNSW leading the way

In recent years, scientists around the world have been developing completely new systems based on exotic materials or light to build a quantum computer. At UNSW, however, the approach has been to use silicon – the material currently used in all modern-day microprocessors, or computer chips. Silicon offers several advantages: the material is cost-effective, already used in almost all commercial electronics, and its properties are very well understood – the result of trillions of dollars of investment into R&D by the computer and electronics industry. Silicon electron “spins” also have very long “coherence times” – this means the quantum data encoded on the spin can remain there for longer periods than it would in most materials, before it is scrambled and lost. This is important for performing successful calculations.

In 1998, former UNSW researcher Bruce Kane first proposed the idea of using silicon as a base material for quantum computing. In a paper in Nature he outlined the concept for a silicon-based quantum computer, in which single phosphorus atoms in an otherwise ultra-pure silicon chip define the qubits.

His visionary work spawned an international effort to develop a quantum computer in silicon, and this latest result represents the biggest achievement en route to realising that dream – a result, researchers say, that could perhaps one day be seen as comparable to the invention of the transistors used in conventional computers.

Timeline of the development of silicon quantum computing in Australia

Read the full article and the timeline of the development of silicon quantum computing in Australia here