D-Wave Quantum Computing Solution Raises More Questions

benonemusic writes "The commercially available D-Wave computer has demonstrated its ability to perform increasingly complex tasks. But is it a real quantum computer? A new round of research continues the debate over how much its calculations owe to exotic quantum-physics phenomena. 'One side argues there is too much noise in the D-Wave system, which prevents consistent entanglement. But in an adiabatic device, certain types of entanglement are not as vital as they are in the traditional model of a quantum computer. Some researchers are attempting to solve this conundrum by proving the presence or absence of entanglement. If they show entanglement is absent, that would be the end of the discussion. On the other hand, even if some of D-Wave's qubits are entangled, this doesn't mean the device is taking advantage of it. Another way to prove D-Wave's quantumness would be to confirm it is indeed performing quantum, and not classical, annealing. Lidar has published work to this effect, but that triggered opposition, and then a counter-point. The debate continues.'"

entangled entanglement

[aleator]

how do you show the presence of entanglement without disturbing it?

Re:Sounds like a scam, quite frankly

[Garridan]

Yeah... I watched a talk by a D-Wave guy. This is a summary of his talk: "So, you have an NP-Complete problem. We have a quantum solver that works on a large graph with a special structure. If you can find a homomorphism from your problem into our graph structure, and you can figure out how slowly to evolve the adiabatic process, then we can solve your problem!"

Okay, that's great. But finding that graph homomorphism? Probably NP-Complete itself. Figuring out how slowly to evolve the system? I have no idea, but the guy said "it's hard", which means the physicists don't have any idea. Maybe also NP-Complete or worse? Who knows. Tell ya one thing, D-Wave sure doesn't.

Why Develop This?

[Dialecticus]

Because *IF* it can be developed, someone will eventually develop it, and probably sooner rather than later. Technological advances depend less on creative genius and more on previous technological advances. It's like how radar was developed simultaneously by about a half-dozen different nations, but they were all trying to keep this supposed strategic advantage secret from one another. It's not that it was a coincidence, but rather that the time was right, and the pieces were all in place.

Isn't it better to develop a quantum computer first, so that you know to stop using vulnerable forms of cryptography? Anything else is just sticking your head in the sand. Failing to develop it yourself will not stop the other guy from doing it.