It's an attitude that seems to have played well with investors, but it still rankles academics. "At an engineering level they've put together a setup that's impressive in various ways," says Scott Aaronson, an MIT professor who studies the limits of quantum computation. "But in terms of the evidence that they're solving problems using quantum mechanics faster than you could classically, I don't think it's there yet." A fierce critic of D-Wave in the years following its 2007 demo, Aaronson softened his stance last year after the company's Nature paper showing quantum effects. "In the past there was an enormous gap between the marketing claims and where the science was and that's come down, but there's still a gap," says Aaronson, who visited the company's labs in February. "The burden of proof is on them and they haven't met the burden yet."
Aaronson's biggest gripe is that the design of D-Wave's system could plausibly solve problems without quantum effects, in which case it would simply be a very weird conventional computer. He and other critics say the company must still prove two things: that its qubits really can enter superpositions and become entangled, and that the chip delivers a significant "quantum speed-up" compared to a classical computer working on the same problem. So far the company has presented proof of neither in a peer-reviewed forum.
If I had to wager today, my money would be on IBM.