I know there are other questions i.e. Do quantum computers manufactured by D-Wave Systems, Inc. work? , What can the D-Wave quantum computer do? , etc. But I can't seem to find my answer. What is getting in the way of determining if D-Wave is a quantum computer? Why can't we just analyze the way they built, and see if it's quantum? Is there a problem with patents getting in the way? Why can we still not tell?
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Why can't we just analyze the way they built, and see if it's quantum?
because the environment can easily get in the way and prevent the quantum effects from creating the speedups they're meant to. Basically you can try to build a quantum computer and end up with a classical computer by mistake that does the same thing (but slower) if it wasn't built carefully enough. The only way we can determine whether it worked for sure is by seeing if the way it runs in practice could only be produced by a quantum computer. So the relevant question is "Can the performance we're seeing be explained classically?" which seems to be a 'yes' so far. It's not so much that things are getting in the way of testing, its that D-wave's claims about what it can do are never substantiated by independent tests. It is being tested, and found to be essentially classical. What might come out of the various improvements they're going to try over the next several years is unknown, but their track record isn't great so far.
answered Jul 8, 2014 at 17:31
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$\begingroup$ I see. But if the company told us how they developed it, wouldn't we be able to answer the question of whether or not it "should" be quantum, without environmental effects? $\endgroup$– user24082Commented Jul 8, 2014 at 17:55
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$\begingroup$ @Anthony yes, and it indeed "should" be, if it were working correctly. We have several possibilities for realizing quantum computers; the environmental effects creeping in and ruining it is always the problem. So this wouldn't be their novel achievement; we've known how to make things that should theoretically be quantum computers for decades. The part where we make the blueprints actually work in real life is where most of the difficulty is in the first place. $\endgroup$ Commented Jul 9, 2014 at 1:50
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$\begingroup$ So then, we have been told how it's developed? Or at least we've been able to figure it out? I'm just curious how protective Dwave is being with regards to their design. $\endgroup$– user24082Commented Jul 9, 2014 at 4:12