David Spain wrote:

Yeah, don't get me started on quantum computers when they are in the
coherent superposition state!

:-)

Actually, I wouldn't mind getting you started. Despite reports of QCs
doing some basic arithmetic, I'm still rather dubious about whether
these things can really work.

Show me factorisation of otherwise intractable composite numbers, and
I'll start to believe

I'll also be highly amused by the abrupt disappearance of important
computer security infrastructure. Well, I did warn them....

Sylvia.