However, unlike most computers, D-wave’s machines, cannot answer any old question. Instead, it is only able to solve so-called “optimisation” problems, where there are a series of criteria all simultaneously competing to be met, and where there is one optimum solution that satisfies the majority of them – for example, the optimal route for a delivery truck to drop off packages, minimising the time and distance travelled.
Lockheed, according to Brownell, hooked up with D-Wave out of a mutual interest in the types of calculations that a quantum computer could perform. “They had algorithms that were applicable to our technology,” he says. “Their particular focus is software verification.”
Software is increasingly at the heart of what defence companies do. For example, the Lockheed Martin F-35 Joint Strike Fighter has what is described as the most complex software system of any modern weapon system, with over 24 million lines of code, according to a 2012 report by the Government Accountability Office. Quantum computing could be used to verify this huge amount of code to ensure the aircraft will operate reliably and safely.
A quantum computer would also be good for a variety of other applications that involve machine learning, says Bo Ewald, the president of D-Wave’s recently launched US business. That may involve what Ewald calls “finding the essence of complex data structures”, something which could be useful for mining social media data or pattern recognition in imagery.
Ewald says that the quantum computer will be able to learn the key characteristics of a particular shape, say a car, by showing it lots of pictures of cars. Once it learns the key characteristics of that shape, it should be able to recognise them more readily than conventional systems. In addition, he says, once it has figured out the characteristics of what make a "car" recognisable, it can be used to "train" conventional computers – such as your mobile phone – how to more easily recognise a car, something which could interest the likes of Google.
Other applications which may interest the Nasa-Google-USRA collaboration range from improving web search and robotics to hunting for exo-planets and optimising air-traffic control. That computer, which will be installed at what is being called the Quantum Artificial Intelligence Lab, will be located at Nasa’s Ames Research Center in California, and is expected to be ready for use later this year.
Bits and bets
But in most cases, proving that a quantum computer will actually perform these sorts of functions faster than a classical computer is still in the realm of theory. As it is, not everyone is even convinced yet that the D-Wave computer is actually using quantum mechanics to make the calculations.
Christopher Monroe, a quantum information researcher of the Joint Quantum Institute and University of Maryland, has expressed doubts in the past about D-Wave’s claims and now says that although the company has made progress in demonstrating its computer’s abilities, it has still not offered proof that it is operating in a quantum state. “I’m not convinced at all it’s a quantum computer,” he says. “But maybe it doesn’t matter.”
What Monroe means is that the D-Wave computer may indeed be able to solve some optimisation problems better than classical computers, as was shown in recent tests, even if the way it works doesn’t involve quantum mechanics. “Given the dearth of publishing from the group, it’s hard to know from all the details whether what they’re observing is a quantum phenomenon,” he says.