Nope. QC allows a very specific attack that breaks the main asymmetric algorithms today, ECC and RSA - there is no meaningful attack on anything else (Grover's

Nope. QC allows a very specific attack that breaks the main asymmetric algorithms today, ECC and RSA - there is no meaningful attack on anything else (Grover's algorithm is technically a sqrt improvement on symmetric algorithms but that isn't close to breaking AES256). There's nothing general purpose in the attack on RSA and ECC: you can use the quantum Fourier transform to find the period of the key, and that period tells you the key. But this is very specific - you have two algorithms that have inherently periodic behavior, where the period is meant to be secret, and so all you need from the QC is the period. It's hard to see how to extend that to other problems. I'm more curious about (and kind of wish more emphasis would be made on) programmable analog computers, which is what it seems QC should be capable of. A lot of the difficult with QC is that people seem really fixated on discrete problems (like factoring \o/) where there's a single correct answer, and so huge amounts of effort and research are going into error correction, etc. There are lots of problems (simulations as in this circuit), where the classical solution simply requires running millions of times with random variance to converge on a sufficiently accurate result where a QC would theoretically be great. The general use problem in that case becomes "how do I convert this classical problem into a QC compatible algorithm".