Spooky interaction: quantum computing will take advantage of the entangled relationship between pairs of particles.
Credit: iStockphoto
Quantum computing has long been the holy grail of physicists bent on transforming the way we communicate and how computers process information. It promises to be a vast improvement on existing computing technology for applications such as cryptography and will be able to calculate algorithms that computers can't handle at the moment.
At least, that's the promise. But in reality, it's a lot more challenging than it might sound.
Over recent months there has been several important advances towards quantum information processing – the basic building blocks for constructing a quantum computer – reported in major journals such as Nature and Science. And in June 2007, the quantum communication distance was broken when one half of an entangled photon pair was sent a distance of 144 km over the Canary Islands (see, Quantum communication breaks distance record, Cosmos Online).
But just how close are we to achieving quantum computing, and how important is it that we get there?
Hot on the trail
When people talk about how anything quantum works, it's not long before words like spooky, nonsensical, or wacky come into the conversation.
By definition, quantum is the singular of quanta, and is an indivisible unit of energy. Quantum mechanics looks at the weird properties inherent in nature that become apparent at atomic and sub-atomic scales, and quantum computing uses these processes to create something capable of forming logical operations.
Back in the 1999 the U.S. National Science Foundation (NSF) wrote that quantum information processing with the capacity of 10 qubits – the quantum equivalent of a classical computer 'bit' – would be possible within a decade, given the rate of progress of research in the quantum realm of physics.
We're not quite there yet, but research today is hot on the trail of quantum computing. Many small demonstrations of the theory are being achieved, as evidenced by the publication of a paper in the British journal Nature in July 2007 describing totally new ways to create the parts necessary for quantum computing.
"There is [currently] a huge amount of effort all over the world," says Andrew White, head of the quantum technology lab at the University of Queensland in Brisbane. But White acknowledges that quantum computers themselves are still at least 20 years away.
He's betting on a working quantum computer – as opposed to today's proof-of-principle demonstrations – by 2025. "I'm pretty sure it won't change the life of my students, but it might change the life of their students," he says.
