I have been following Scott's site for several years. He is at the top of his field, one of the most qualified quantum computing theorists. Sometimes his sarcasm is juvenile and falls flat, but this post is classic. Yes you would have had to been following along to appreciate it. And it would help to know D-wave at one point actively recruited Scott.If you want to know whether or not quantum computation is taking place, this is your man.
If you are interested in more of the background, Scott provied this link to his previous posts that touch on D-wave http://scottaaronson.com/blog/?cat=20
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."
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.
This post makes the assumption that one has been following this drama for a long time in detail. I know there was a bit of controversy around D-Wave a long while back, but that's faded from memory now. The Google post brought them back into memory, but I found it hard to make it past the first few back-and-forths in Scott's post.
Can someone clarify what the situation is here without the "socratic-dramatic"? :)
D-Wave keeps making the news with their 'adiabatic quantum computers' solving puzzles and doing pattern-matching. They claimed last year that they built a 128-qubit quantum chip while other research efforts only managed couple of qubits.
The problem with all this is that they've still not managed to prove that their hardware is actually a quantum computer (in the sense that there's usefully entangled qubits)
In a previous press interview they were ripped to shreds - rightfully so - for being so vague about how they knew that the devices they build are quantum computers. At one point someone asked them about a really simple test: To maintain a quantum superposition the hardware must be kept close to 0 Kelvin. Therefore they should be able to slowly increase the temp in their rig and at some point it should change behavior - it should revert to the classical physical behavior and the quantum effects should stop. D-Wave admitted that they've not done this simple yet extremely obvious test. And today, a year later, we're still no further.
The only logical conclusion is that they've not succeeded in making a 'real' quantum processor.
"Keep in mind that we’re delivering a product—serving our customers, by solving the 4-by-4 Sudoku puzzles they rely on to keep their businesses running."
I highly recommend reading further on his site, including his papers and lecture notes. I especially recommend his lecture notes "Great Ideas in Theoretical Computer Science" http://stellar.mit.edu/S/course/6/sp08/6.080/materials.html and "Quantum Computing Since Democritus" http://www.scottaaronson.com/democritus/
Enjoy.