D-Wave Systems in British Columbia, Canada, is the only company in the world selling quantum computers, and it counts Google and NASA among its customers.
But after four years on the market there is still no clear evidence its machines can solve problems faster than ordinary computers.
Now the firm has announced the D-Wave 2X, and claims it is up to 15 times faster than regular PCs. However, outside experts contacted by New Scientist say the test is not a fair comparison.
The theory behind such computers, which exploit the weird properties of quantum mechanics, is sound. A device built using qubits, which can be both a 0 and a 1 at the same time, promises to vastly outperform regular binary bits for certain problems, like searching a database.
But putting that theory into practice has proved tricky, and though experiments show the D-Wave machines display quantum behaviour, it’s not clear this is responsible for speeding up computation.
The D-Wave 2X is the company’s third computer to go on sale, and features more than 1000 qubits – double the previous model. Other changes have reduced noise and increased performance, says D-Wave’s Colin Williams.
D-Wave put the machine through its paces with a series of benchmark tests based on solving random optimisation problems.
For example, imagine a squad of football players, all with different abilities and who work better or worse in different pairs. One of the problems is essentially equivalent to picking the best team based on these constraints.
D-Wave compared the 2X’s results against specialised optimisation software running on an ordinary PC, and found its machine found an answer between two and 15 times as quickly. And if you leave aside the time it takes to enter the problem and read out the answer, the pure computation time was eight to 600 times faster.
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