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.

This video is not supported by your browser at this time.
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: Physicists design quantum switches which can be activated by single photons

More information: DOI: 10.1038/nature11449

Related Stories

Single electron reader opens path for quantum computing

Sep 27, 2010

Researchers from University of New South Wales (Australia), University of Melbourne (Australia), and Aalto University (Finland) have succeeded in demonstrating a high-fidelity detection scheme for the magnetic ...

Quantum age edges closer

Jan 05, 2010

(PhysOrg.com) -- The arrival of superfast quantum computing is closer following recent breakthroughs by an international team led by UNSW researchers.

Scientists build 'single-atom transistor'

Dec 06, 2009

(PhysOrg.com) -- Researchers from Helsinki University of Technology (Finland), University of New South Wales (Australia), and University of Melbourne (Australia) have succeeded in building a working transistor, ...

Single-atom transistor is 'perfect'

Feb 19, 2012

In a remarkable feat of micro-engineering, UNSW physicists have created a working transistor consisting of a single atom placed precisely in a silicon crystal.

Recommended for you

Could 'Jedi Putter' be the force golfers need?

Apr 18, 2014

Putting is arguably the most important skill in golf; in fact, it's been described as a game within a game. Now a team of Rice engineering students has devised a training putter that offers golfers audio, ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Sonhouse
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.

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...