> physics will somehow magically forbid us from scaling up quantum computers Not magically >with predictable error rates etc This isn't my field of expertise

> physics will somehow magically forbid us from scaling up quantum computers Not magically >with predictable error rates etc This isn't my field of expertise, but my understanding is that this is precisely the issue: these predictable error rates are predicted to be a deal-breaker for the amount of qbits that are needed to break RSA with today's commonly-used key lengths. In my view, the fact that the error rates appear to match predictions so far, only sustain this point. A reason to be optimistic could be that sometimes we get to hear about new promising error-correction techniques though. We'll see how future development goes, in the end it is hard to predict what will happen. But this is also why I think we should be more careful in claiming that quantum computer will break classical cryptography in the short to medium term.