[miles7]

To your first question, probably not any time soon. The main quantum algorithm for breaking (certain types of) cryptography is Shor’s algorithm, and will probably need error-corrected quantum computers with at least hundreds of logical qubits to beat classical methods. That translates into thousands of physical qubits of very high quality with exquisite control over them and interconnectivity.

If my answer makes it sound like the prospect of quantum computers is overhyped that’s because it most definitely is.

A somewhat smaller version of this quantum simulator from Harvard has been studied a lot in the past and given high enough quality results on various benchmark tests that the community is convinced the author’s claims about it are legit.