My take away from this article at Physics Buzz is that no one can tell whether the D-Wave computer recently aquired by Nasa and Google is an actual quantum computer or just a very powerful machine that uses traditional methods of computation:
Scientists have been debating D-Wave’s quantumness since the company announced its first device in 2004. It is an argument that continues both online, in blog posts and forums, and in scientific journals.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.