Silicon back in the race for quantum computers

Researchers have made a silicon chip that can control and observe individual electrons and they are now using this chip to make quantum test chips.

The potential speed and power of a quantum computer is known to far exceed even the biggest supercomputers. What is still unclear though is the best method to build one.

Teams around the world are racing to create the first quantum computer with 10 or more competing technologies being investigated including: photonics; nuclear magnetic resonance; superconducting materials; ion traps; and silicon technology.

One of the advantages of silicon technology is that quantum chips could be integrated with current computer chips, making it easier to build a large-scale quantum computer.

Susan Angus and her CQCT colleagues, working at the University of New South Wales, were able to isolate a few electrons on a nano-scale silicon island and then controllably add or remove electrons just one at a time. The researchers have also used this technique to make a fast and sensitive detector in silicon, which is able to sense the movement of just a single electron nearby.

“Building a quantum computer involves perfect control of the most fundamental properties of our universe. Controlling and observing individual electrons is an important step towards that goal,” said Angus.

A quantum computer is not just a faster, smaller version of current machines, it will operate using the strange principles of quantum physics. One of the key features is that instead of using the binary system, where the computer uses tiny switches or ‘bits’ that are either on or off, the basic units of a quantum computer, the ‘qubits’, can be both on and off simultaneously.

“It is impossible to predict the impact that this incredibly powerful new form of computing will have — just like it was difficult to predict the impact that ordinary computers have had on our society. We do know though there are a number of jobs that a quantum computer will be able to do much more quickly — for example, it will speed up drug design, genetic testing and climate analysis, just to name a few,” said Angus.

Angus’s work is the subject of a provisional patent and has been published in Nano Letters and Applied Physics Letters.