> Quantum computation is the same. You figure out how to build gates (there are dozens of competing ideas), and then it's just plugging them together in the rig

> Quantum computation is the same. You figure out how to build gates (there are dozens of competing ideas), and then it's just plugging them together in the right way. Not exactly. Quantum computers are a kind of analog computers based on quantum mechanics and there are several different models for doing quantum computation ---only one of them is based on gates. Annealers such as D-Wave aren't based on quantum gates. They instead slowly anneal the system to its ground state (while avoiding states corresponding to a local minima in energy), and the usefulness of this lies in the fact that calculation of ground state of a system is often an extremely difficult problem, and that you can map your NP problem onto calculation of the ground state in certain cases.