Calculation is no optical illusion for light-based computer

Published on Thursday 3 September 2009 21:48

SCIENTISTS have hailed the first ever calculation performed on an optical computer chip which uses light particles rather than traditional circuitry – despite it being slower than a schoolchild.

The optical quantum chip uses single particles of "whizzing" light which could eventually pave the wave for a "super-powerful quantum computer", smaller and faster than anything we have now.

The photonic chip, roughly the size of a penny, managed to find the prime factors of 15, and give the answer – three and five (3 X 5). But it was the principal rather than the task that was important to the team at Bristol University.

Project spokeswoman Cherry Lewis said: "We are almost getting to the point now where conventional computers cannot go any smaller so we need to go down a completely new route. We are talking nano-scale. Particles of light."

Quantum technology aims to exploit the unique properties of quantum mechanics – the physics theory that explains how the world works at microscopic levels.

Quantum particles, such as photons, can exist in a "superposition" of two states at the same time – in marked contrast to the transistors in a PC. Photons are also relatively noise-free and allow information can be transmitted at the speed of light.

The technology could eventually be applied to making internet connections secure and to developing new materials and medicines.

The results are reported by the Bristol team of physicists and engineers in the latest issue of Science.

Professor Jeremy O'Brien, Director of the Centre for Quantum Photonics, who led the research, said: "The realisation of a quantum algorithm on a chip is an extremely important step towards an all-optical quantum computer."