Computer technology set for quantum leap

SILICON chips that exploit the properties of quantum physics could be common components in laptops and smart phones within a few years, say scientists.

British-led technology is set to revolutionise computing using circuits that operate with light instead of electricity, it is claimed.

For the first time, they will offer a practical way of harnessing subatomic interactions so strange they spooked Albert Einstein.

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The result could be blindingly fast search engines, encryption systems that cannot be cracked, and computers vastly more powerful than anything in use today.

Super-secure communication devices expected to appear in the next three years could effectively end hacking and identity theft. In another decade, quantum computers could be outperforming their conventional counterparts.

And by 2525 quantum circuits might be everywhere – sitting inside laptops and phones, helping to design new drugs and smart materials, predicting the weather with unprecedented accuracy, and keeping bank accounts and sensitive information safe.

Scientists will be showing off their quantum circuits at the British Science Festival, which opens at the University of Aberdeen today.

“It had previously been thought that a large-scale quantum computer will not become a reality for at least another 25 years,” said Professor Jeremy O’Brien, director of the Centre for Quantum Photonics at the University of Bristol.

“However, we believe that, using our new technology, such a device, in less than ten years, will be performing important calculations that are outside the capabilities of conventional computers.”

An ordinary computer relies on logic gates – essentially switches – that are either on or off and which encode data into “bits” represented by ones and zeros. But a quantum computer’s switches can be on, or off, or simultaneously on and off.

A “qubit” can exist as a zero, a one, or a “superposition” of both these states at the same time. Multiple qubits can be in numerous inbetween states.

This is possible because of quantum effects only seen at the subatomic level that appear to defy common sense.

Particles such as photons, packages of light, can be in two places at once or “entangled” so they influence each other instantaneously, no matter how far apart they are. Einstein found entanglement so hard to swallow he dismissed it as “spooky action at a distance”.

Prof O’Brien’s team has found a way to build photon-channelling quantum circuits out of silicon, the cheap material used in computer chips all over the world.

This opens up the possibility of mass-producing quantum chips that can be used alongside ordinary microelectronic components.

The extra cost of producing a mobile phone containing one or two quantum circuits would be minimal, say scientists.