Better control of building blocks for quantum computer

December 23, 2010
Artist’s impression of the spin-orbit qubit. Like in a yo-yo toy, by moving the electron one controls its spin. Credit: Gemma Plum

Dutch scientists from the Kavli Institute of Nanoscience at Delft University of Technology and Eindhoven University of Technology have succeeded in controlling the building blocks of a future super-fast quantum computer. They are now able to manipulate these building blocks (qubits) with electrical rather than magnetic fields, as has been the common practice up till now. They have also been able to embed these qubits into semiconductor nanowires. The scientists’ findings have been published in the current issue of the science journal Nature (23 December).

A qubit is the building block of a possible, future quantum computer, which would far outstrip current computers in terms of speed. One way to make a qubit is to trap a single electron in semiconductor material. A qubit can, just like a normal computer bit, adopt the states '0' and '1'. This is achieved by using the spin of an electron, which is generated by spinning the electron on its axis. The electron can spin in two directions (representing the '0' state and the '1' state).

Nanowire-1-WEB: Artist's impression of nanowire qubits. Credit: Gemma Plum

Until now, the spin of an electron has been controlled by magnetic fields. However, these field are extremely difficult to generate on a chip. The electron spin in the that are currently being generated by the Dutch scientists can be controlled by a charge or an electric field, rather than by magnetic fields. This form of control has major advantages, as Leo Kouwenhoven, scientist at the Kavli Institute of at TU Delft, points out: "These spin-orbit qubits combine the best of both worlds. They employ the advantages of both electronic control and information storage in the electron spin."

Scanning electron image of the nanowire device with gate electrodes used to electrically control qubits, and source and drain electrodes used to probe qubit states.

There is another important new development in the Dutch research: the scientists have been able to embed the qubits (two) into nanowires made of a semiconductor material (indium arsenide). These wires are of the order of nanometres in diameter and micrometres in length. Kouwenhoven: "These nanowires are being increasingly used as convenient building blocks in nanoelectronics. Nanowires are an excellent platform for quantum information processing, among other applications."

Explore further: Single electron reader opens path for quantum computing

More information: Nadj-Perge, S, et al. (2010) Spin-Orbit qubit in a semiconductor nanowire. Nature 468, 1084 – 1087.

Related Stories

Single electron reader opens path for quantum computing

September 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 state of a ...

Spin-polarized electrons on demand

January 21, 2009

Many hopes are pinned on spintronics. In the future it could replace electronics, which in the race to produce increasingly rapid computer components, must at sometime reach its limits. Different from electronics, where whole ...

Spin-polarized electrons on demand

January 15, 2009

Many hopes are pinned on spintronics. In the future it could replace electronics, which in the race to produce increasingly rapid computer components, must at sometime reach its limits. Different from electronics, where whole ...

Researcher discovers how to control semiconductor nanowires

June 13, 2006

Jorden van Dam, researcher at the Kavli Institute of Nanoscience Delft (Holland), has succeeded in largely controlling the transportation of electrons in semiconductor nanowires. Van Dam moreover discovered how to observe ...

Turning down the noise in quantum data storage

January 19, 2010

Researchers who hope to create quantum computers are currently investigating various methods to store data. Nitrogen atoms embedded in diamond show promise for encoding quantum bits (qubits), but the process of reading the ...

Recommended for you

Two teams independently test Tomonaga–Luttinger theory

October 20, 2017

(Phys.org)—Two teams of researchers working independently of one another have found ways to test aspects of the Tomonaga–Luttinger theory that describes interacting quantum particles in 1-D ensembles in a Tomonaga–Luttinger ...

Using optical chaos to control the momentum of light

October 19, 2017

Integrated photonic circuits, which rely on light rather than electrons to move information, promise to revolutionize communications, sensing and data processing. But controlling and moving light poses serious challenges. ...

Black butterfly wings offer a model for better solar cells

October 19, 2017

(Phys.org)—A team of researchers with California Institute of Technology and the Karlsruh Institute of Technology has improved the efficiency of thin film solar cells by mimicking the architecture of rose butterfly wings. ...

Terahertz spectroscopy goes nano

October 19, 2017

Brown University researchers have demonstrated a way to bring a powerful form of spectroscopy—a technique used to study a wide variety of materials—into the nano-world.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Quantum_Conundrum
not rated yet Dec 23, 2010
Soooo...

When do we start to see the first quantum chips?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.