Quantum computers - why would you want one?
Box 2 | What are we up to here in Australia?
The drive to develop practical quantum computers is well under way in many advanced countries, though everyone agrees we still have a long way to go. Australia is well up with the pack; in some areas we can claim leadership.
With a number of universities active here, the effort is being coordinated through the Centre for Quantum Computer Technology, set up in 2000.
The research programs are diverse, as they have to be in such a new area. Some concentrate on the theory of quantum computing. Others are trying out a range of possible practical systems that quantum computers might use. Some of these employ semiconductor materials like silicon, as today's computers do; others are trying to use particles of light (known as photons) to store and compute the data.
Here are a few recent highlights:
- Researchers have found a way to trap up to ten 'ions' (atoms which have lost some electrons) in a vacuum chamber where they can be controlled and manipulated by a laser. Such ions could serve as the qubits that will store data in a quantum computer.
- Scientists have been investigating new ways to generate photons as current photon production methods are expensive and inefficient. Experiments are being carried out using engineered crystals, mirrors, lenses and beam splitters for photon production.
- In another research program, the aim is to build a quantum computer from the 'bottom up', by placing atoms on a surface which is then incorporated into nano-scale structures. This contrasts with attempts to make large devices even smaller, as is happening in computer technology today.
- Ion implantation is another subject under intense study. Advanced technologies can precisely place single atoms of elements such as phosphorus onto a surface. Researchers expect that they can get these to interact and behave as qubits for storage of data or as the devices that do the computing.
Boxes
Box 1. Into the nanoworld
Box 3. So when will we have one?
Related sites
Griffith physicists make quantum leap in race for a supercomputer (Griffith University, Australia)
Shining light in quantum computing (The University of Queensland, Australia)
Quantum computing (The Science Show, 7 May 2005, Australian Broadcasting Corporation)
A quantum leap in computing (The University of Melbourne, Australia)
Posted August 2007.