The ones I find the most convincing are the ones that try to find a "signature" of quantum computation, by setting the system up with a certain connectivity that will cool down into certain ground states with certain probability iff it's quantum. I like these. There was one from Boixo, but I guess Vazirani's group at Berkeley figured out that this test wasn't good enough to differentiate. There was another, again, which Boixo is on, from Ronnow et. al. which came up with another signature, and they decided that it wasn't quantum.
If you've been doing superconducting qubits for a while, you notice that they're using a qubit design which even the inventor has abandoned at this point. If you're an experimental physicist, you notice that the whole thing is a poorly designed scientific experiment. If you're just a casual observer, and you listen to the language they use to describe their product, you notice that their wording is very slimy. I don't believe it's quantum.
I also think a room temperature annealer ASIC could be very, very cool. An analog computer sort of thing. Would LOVE to see this.
By superconducting qubits I assume you're referring to a general approach for creating qubits that you can use for computation (I'm also assuming the 'superconducting' refers to getting some material into a superconducting state at which point the physical/quantum properties are useful). Is that right?
And when you say the inventor has abandoned their qubit design, do you mean the person that came up with that particular approach? Or the credited inventor of the d-wave? Or something else?
The small amount of stuff I've read examining their claims definitely made it seem like they were weasel-wording things, but I've never understood enough about quantum mechanics (or quantum computing) to attempt to examine them directly. Thanks.
I hadn't realized that annealing could be done in an analog fashion - that's pretty cool. I can see how in that case an ASIC could actually dramatically outperform a digital model, then?
Also, 'room temperature' - does the D-Wave have to be cooled to some absurdly low temperature to work? I can see how that would be necessary if it relies on superconductivity.
Yeah, 20 millikelvin. It's cooled with liquid Helium.
Sure, it sound rather indirect but if you could put water in your car and beat competitors consistently, you'd be truly the best artist ever or have some energy-from-hydrogen scheme going on.
As far as I understand the whole thing, they are just "solving" the minimization of some tunable potential function by just being pushed into such potential and allowed to relax to the lowest energy state -- it is like finding a lowest point of a hole by throwing a ball into it and looking where it stops (and being happy that it runs faster than a numeric code simulating the physics of such ball). The quantum part here is only the fact that quantum effects should help the search to escape local minima, but the speed-up mostly comes from the fact it is basically an analog device.
Perhaps at that point the classical solvers could be furthered improved to become faster than D-Wave II. As the set of problems is further narrowed, someday we may have a set of problems at which D-Wave II cannot be beat by a classical solver. Perhaps that will be evidence that D-Wave II is a quantum machine.
Or not.