A Quantum Leap in Computers

The following is a re-posting of an article on Science Matters about the beginning of the new generation of computers with power far beyond what currently exists. So great, in fact, that its full potential is unknown because it will be capable of things that we haven't dreamed up yet. It is a true paradigm shif and it all begins with the first successful qubit, the quantum computer equivalent of the transistor in the present generation of computers. Congratulations Australia.

First working ‘qubit’ a quantum computing breakthrough

News — By Esther Faine-Vallantin on 26th September, 2012 at 10:33 am


A group of Australian and British researchers, including some from the University of Melbourne, have published a paper in the journal Nature about their creation of the first working ‘qubit’ based on a single atom in silicon.

Dr. Andrea Morello and Scientia Professor Andrew Dzurak, from the University of New South Wales School of Electrical Engineering and Telecommunications, led the research team of researchers from the UNSW, the University of Melbourne and London’s University College.

In 2010, this same research group demonstrated the ability to read the state of an electron’s spin.

Following on from this, their work effectively used a microwave field to control the spin – or magnetic orientation – of an electron bound to a single atom in order to read and write information. This second step makes it possible to actually operate a quantum bit.

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

Artist Tony Melov’s impression of a phosphorus atom (red sphere in the middle of an electron ‘cloud’. The arrow indicates the spin direction) connected to a silicon single-electron transistor. Microwave radiation (light blue) is used to ‘write’ data into the electron spin. Credit: Tony Melov

According to Dr. Morello, quantum computers have the potential to solve complex problems that existing computers, including supercomputers, cannot. “These include data-intensive problems, such as cracking modern encryption codes, searching databases, and modelling biological molecules and drugs.”

The use of silicon is important as it relates to the manufacturability of quantum computing. The entire computing industry is familiar with silicon as a material and therefore its use could facilitate the more rapid development of quantum computers.

Professor David Jamieson, of the University of Melbourne’s School of Physics led the team that implanted the phosphorus atom into the silicon device. Professor Jamieson said: “Our team has the unique expertise to implant a single phosphorus atom into the correct location of a nanoscale quantum device.”

David Jamieson (left) and Changyi Yang with the the special quantum computer device chip holder ready to be loaded into the ion implantation system.

This implantation technique meant that the UNSW team could control the quantum mechanical state of the single electron in orbit around the engineered atom. Jamieson believes that “this technique could have wider applications unlocking the potential of smaller classical silicon transistors predicted by Moore’s Law”.

The research team will continue their investigations, now focussing on how to combine pairs of qubits in order to establish a two-qubit logic state for processing.