Hopefully someone can expand on these comments since I'm not an expert, but I know a little. D-Wave [1] is shipping quantum computers with thousands of qubits.

Hopefully someone can expand on these comments since I'm not an expert, but I know a little. D-Wave [1] is shipping quantum computers with thousands of qubits. The difference seems to be that D-Wave qubits are not generalized qubits, but rather they are simply designed to solve problems using quantum annealing [1]. Annealing is just one algorithm which efficiently (but probabilistically) looks for the global minimum of a function, but it is prone to getting stuck in local minima. Quantum annealing exploits quantum phenomena to do this better and probably more efficiently [2]. On the other hand, we have "general" qubits: these can implement and carry out any arbitrary quantum computing algorithm (for example, Grover's search algorithm or Shor's factorization algorithm). It seems to me that researchers at Alphabet, Rigetti, Intel, IBM, etc. are trying to build these general qubits, since that's where we can finally unlock the full power of quantum computing. It's also much harder to build these general qubits, and that's why we only see 17 qubits announced here, or Google claiming to be working on 49 qubits [3]. [1] https://www.dwavesys.com/sites/default/files/D-Wave%202000Q%20Tech%20Collateral_0117F2.pdf https://www.dwavesys.com/sites/default/files/D-Wave%202000Q%... [2] https://en.wikipedia.org/wiki/Quantum_annealing https://en.wikipedia.org/wiki/Quantum_annealing [3] https://www.bloomberg.com/news/articles/2017-07-17/google-s-quantum-computing-push-opens-new-front-in-cloud-battle https://www.bloomberg.com/news/articles/2017-07-17/google-s-...