If you are interested in more of the background, Scott provied this link to his previous posts that touch on D-wave <a href="http://scottaaronson.com/blog/?cat=20" rel="nofollow">http://scottaaronson.com/blog/?cat=20</a><p>A commentor to the most recent post points to this rebuttal <a href="http://scienceblogs.com/pontiff/2009/12/in_defense_of_d-wave.php" rel="nofollow">http://scienceblogs.com/pontiff/2009/12/in_defense_of_d-wave...</a><p>But it all boils down to this, as Scott replies in the comments "...the elephant that’s missing from the room, namely the evidence for coherence and multi-qubit entanglement. Without that, the car never leaves the garage. So, yes, write an unbiased review of the leather seats, but don’t pass over in silence the fact that nobody’s seen the engine."<p>It's possible to build in hardware an engine that will efficiently compute a particular class of problem. It may even be useful. That does not make it a quantum computer.