Feeds

Boffins spin up working Qubit in silicon

Quantum researcher outlines how to build a quantum logic gate

  • alert
  • submit to reddit

Secure remote control for conventional and virtual desktops

The University of New South Wales' School of Electrical Engineering and Telecommunications has created what it says is the world's first working qubit based on a single atom.

Detailed in a new Nature paper, A single-atom electron spin qubit in silicon, the qubit relies on the ability to impart “spin” to an electron bound to a single phosphorus atom, then read that spin.

Spin is the magnetic orientation of an electron and is a very useful quality as it can be used to make matter behave in useful ways. IBM, for example, is keen on controlling spin as a way of assembling denser storage media.

The UNSW team, which worked with University of Melbourne and University College, London, researchers, managed to impart a certain spin onto an electron and then read it back. Reading spin is a decidedly non-trivial task, as spin boffins told us back in July.

The working qubit was built by using a microwave field to control the electron, which the research team says “was implanted next to a specially-designed silicon transistor.”

The transistor in question is not that created by UNSW researcher Dr Martin Fuechsle, which we reported on last February. Dr Andrea Morello from the team behind this new paper describes that device as a transistor built at quantum scale, but not a carrier of quantum information.

Dr Morello explained to El Reg that the transistor described in the new paper is set up to read the electron's spin. If it is spinning "down" energy cannot flow into the transistor. If the electron spins "up", current flows, the transistor catches it and the team can see the results on a garden-variety oscilloscope.

The result, Dr Morello said, is “... the quantum equivalent of typing a number on your keyboard” and pointing out that doing so in silicon is important, as it is “a material that offers the advantage of being well understood scientifically and more easily adopted by industry.”

Another of the researchers, Professor Andrew Dzurak, is a little more effusive, describing the rig as "a remarkable scientific achievement – governing nature at its most fundamental level.”

The team now hopes to assemble two working qubits into a logic gate, the next logical step towards building a quantum computer. Morello said building such a device won't require step into the unknown, but will take a year or two to accomplish.

Prototype devices have already been built, he said, outlining a design that will see two transistors placed about 15 nanometres apart. One phosphorous atom will sit atop each, with the orbits of each atom's electrons intersecting. "You will only be able to impart spin on one atom depending on the spin of the other," he explained. "That's an interaction that allows logical operations." ®

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 microwave radiation (light blue) is used to ‘write’ information on the electron spin. Credit: Tony Melov

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 microwave radiation (light blue) is used to ‘write’ information on the electron spin.

Credit: Tony Melov

Next gen security for virtualised datacentres

More from The Register

next story
Vulture 2 takes a battering in 100km/h test run
Still in one piece, but we're going to need MORE POWER
TRIANGULAR orbits will help Rosetta to get up close with Comet 67P
Probe will be just 10km from Space Duck in October
Gigantic toothless 'DRAGONS' dominated Earth's early skies
Gummy pterosaurs outlived toothy competitors
Boffins ID freakish spine-smothered prehistoric critter: The CLAW gave it away
Bizarre-looking creature actually related to velvet worms
CRR-CRRRK, beep, beep: Mars space truck backs out of slippery sand trap
Curiosity finds new drilling target after course correction
'Leccy racer whacks petrols in Oz race
ELMOFO rakes in two wins in sanctioned race
What does a flashmob of 1,024 robots look like? Just like this
Sorry, Harvard, did you say kilobots or KILLER BOTS?
NASA's rock'n'roll shock: ROLLING STONE FOUND ON MARS
No sign of Ziggy Stardust and his band
Why your mum was WRONG about whiffy tattooed people
They're a future source of RENEWABLE ENERGY
prev story

Whitepapers

5 things you didn’t know about cloud backup
IT departments are embracing cloud backup, but there’s a lot you need to know before choosing a service provider. Learn all the critical things you need to know.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.
Rethinking backup and recovery in the modern data center
Combining intelligence, operational analytics, and automation to enable efficient, data-driven IT organizations using the HP ABR approach.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.