H.Baker: Re quantum computation:
I'm still extremely uneasy with Shor's quantum factoring algorithm. The problem isn't with his algorithm, per se, but with the basic quantum model on which it is based. Leaving aside the potentially unsolvable problem of achieving the amount of isolation from the environment required to factor a large number, I'm not so sure that the underlying physics can represent the quantum phases to the amount of precision required to factor very large numbers. --see this 2003 paper by me, which argues that "quantum computers won't work." More precisely, it argues that in an computer-sciency asymptotic limit they will be no more powerful (up to polynomial factor) than old-fashioned computers. I personally find my counterargument quite convincing, despite fact few paid attention to it. However, the asymptopia in which my argument is convincing, leaves a lot of room below it, i.e. you might be able to build a quantum computer to factor 100000-digit numbers, that might not be asymptopia yet! So my argument is not so great in that sense. http://rangevoting.org/WarrenSmithPages/homepage/works.html paper #64 Argument against quantum computers (or against certain decoherence models) http://rangevoting.org/WarrenSmithPages/homepage/whywontwork2.ps