Google continues to experiment with quantum computing <https://arstechnica.com/science/2019/09/paper-leaks-showing-a-quantum-computer-doing-something-a-supercomputer-cant/>. This latest result (albeit preliminary) sounds impressive: But that seriously understates what's going on here. Every calculation that's done on a quantum computer will end up being a measurement of a quantum system. And in this case, there is simply no way to get that probability distribution using a classical computer. With this system, we can get it in under 10 minutes, and most of that time is spent in processing that doesn't involve the qubits. As the researchers put it, "To our knowledge, this experiment marks the first computation that can only be performed on a quantum processor." but it is still just reinforcing the point I made earlier <https://list.waikato.ac.nz/hyperkitty/list/wlug(a)list.waikato.ac.nz/thread/KZNHRQBERD3UUWQ53DQDGXMDLCIXBZMX/>, that quantum computers are just a reboot of the old idea of “analog” computers. These are able to do fast simulations of physical systems (in this case, a quantum probability distribution), to limited precision. But they continue to be useless for number-theoretic calculations, such as factoring large integers. Or code cracking.