Canadians claim quantum computing breakthrough

Stephen Withers
Monday, 12 February 2007 05:29

Your IT - Home IT

Canadian company D-Wave Systems hopes to be the first to demonstrate a commercial quantum computer.

Quantum computing (in this writer's limited understanding) is based on the idea that at a quantum level, states are undetermined until they are observed. Thus while a conventional computer's bits are always on or off, a quantum computer's qubits (quantum bits) exist in both states at the same time. A quantum computer 'collapses' these states to generate a solution.

So far, quantum computing has been limited to research laboratories. D-Wave is thought to be the only company currently developing commercial quantum  computers. D-Wave's Orion - to be demonstrated on February 13 - is a 16-qubit design capable of performing 64,000 simultaneous calculations.

One concern about quantum computing is that it has the potential to factor large integers extremely quickly, which would provide a way of breaking widely-used encryption schemes.

Quantum physics also can be applied to the problem of distributing encryption keys in a highly secure manner - if an intruder attempts to intercept the photons carrying the information, their state changes in a way detectable by the receiver. That's not much help if quantum computing provides a means of decryption without requiring knowledge of the keys.

However, D-Wave's device is not suited to cryptographic problems. Instead, it solves multivariable combinatorial problems, founder and CTO Geordie Rose told EETimes.

A simple example of what's known as an NP-Complete' problem is the travelling salesman problem (determining a route starting and ending at the same city, but visiting a number of others exactly once at the lowest total cost). Equivalent problems occur in manufacturing and other areas.

The reason why these combinatorial problems are important is that they occur frequently in real life, and the time needed to solve them on a conventional computer goes up rapidly as they become more complicated (eg, the number of cities to be visited increases).