Single-atom writer a landmark for quantum computing

Sep 19, 2012
This is an artist’s impression of a phosphorus atom (red sphere surrounded by electron cloud, with arrow showing the spin direction) coupled to a silicon single-electron transistor. A burst of microwaves (blue) is used to ‘write’ information on the electron spin. Credit: Tony Melov

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 , of an electron bound to a single embedded in a .

"For the first time, we have demonstrated the ability to represent and manipulate data on the spin to form a , 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 ," says Dzurak.

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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.

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 and drugs."

The new finding follows on from a 2010 study also published in Nature, in which the same UNSW group demonstrated the ability to read the state of an electron's spin. Discovering how to write the now completes the two-stage process required to operate a quantum bit.

Project leaders Andrew Dzurak (left) and Andrea Morello (right), with Ph.D. student and lead author Jarryd Pla (centre). Credit: University of New South Wales

The new result was achieved by using a microwave field to gain unprecedented control over an electron bound to a single phosphorous atom, which was implanted next to a specially-designed . Professor David Jamieson, of the University of Melbourne's School of Physics, led the team that precisely implanted the phosphorous atom into the silicon device.

UNSW PhD student Jarryd Pla, the lead author on the paper, says: "We have been able to isolate, measure and control an electron belonging to a single atom, all using a device that was made in a very similar way to everyday silicon computer chips."

Team leader David Jamieson (left) with Changyi Yang in the CQC2T cleanrooms at the University of Melbourne with the special quantum computer device chip holder ready to be loaded into the ion implantation system. Credit: University of Melbourne

As Dr Morello notes: "This is the quantum equivalent of typing a number on your keyboard. This has never been done before in silicon, a material that offers the advantage of being well understood scientifically and more easily adopted by industry. Our technology is fundamentally the same as is already being used in countless everyday electronic devices, and that's a trillion-dollar industry."

The team's next goal is to combine pairs of quantum bits to create a two-qubit logic gate – the basic processing unit of a quantum computer.

Explore further: Duality principle is 'safe and sound': Researchers clear up apparent violation of wave-particle duality

More information: DOI: 10.1038/nature11449

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4 / 5 (1) Sep 19, 2012
In the video, in one part he is sitting next to a liquid helium dewar, which answers my question, it would have to be near 0 degrees K so we won't be seeing this effect at room temperature any time soon....
Congratulations on your groundbreaking work!

One question, since they are using microwaves as the moment flipper, how many of these devices could be jammed together and still work, it would seem the magnetic moment jump would have to be done by higher frequencies, IR maybe, to be able to use a number of them close packed.