Science Forums 2

[CraigD]

For some non-fictional speculation about peculiar quantum mechanical effects in brain tissue, I recommend a quick, index-guided read of parts of Roger Penrose’s 1989 “The Emperor’s New Mind”, after which You’ll likely find it hard to resist a slow cover-to-cover read. Regardless of one’s agreement of disagreement with sir Roger’s speculations, I think you’ll have to conclude that he’s an interesting, articulate, very bright fellow.

Though even Penrose and folk interested in his quantum brain ideas tend to confess having only a vague idea of the implications of their speculations, they’ve done some pretty detailed and interesting neuroanotomical studies.

Originally Posted by alternative3

I'm trying to design a fictional way for the brain to act as an active quantum computer - rather than a passive one. Passive, for me, meaning that the brain functions as a quantum computer simply to process and store information. Versus an active computer, meaning the brain can interface, encode and manipulate the quantum universe. If an active quantum computing brain can manipulate the quantum universe, what are the implications?

I’d believe what you’re calling an “passive quantum computer” is what theorists call a “quantum computer”, and what you’re calling an “active quantum computer” is what conventional theorists call “not a quantum computer”, or “ordinary matter and energy”.

The essence of a quantum computer is that it performs some calculation “coherently”, AKA in a “superposition of states”. A widely discussed (and written about in SF – Robert Sawyer’s 2003 Hugo winning “Hominids” and sequels have some of the clearest examples) example is the problem of finding a large prime factor P of a large composite number C, such as the kind used in RSA encryption. A quantum computer would use some truly random process to simply “guess” every possible integer P (it wouldn’t even have to assure P is prime), divide C by P, and, if the remainder is zero, “break out” of its coherent state by interacting with the external universe. To the outside observer, it would appear that the quantum computer was astronomically lucky, always guessing right in one processing cycle, because none of the huge number of incorrect guesses made in the same huge number of parallel universe ever signal success.

The important point is that a quantum computer, if it works (and there’s growing suspicion that they can’t be made to, at least not for useful tasks like factoring large numbers), works because it doesn’t manipulate the quantum universe outside of the absolutely isolated confines of it own physical extent. So the “active quantum computer” you describe is, by definition, the description of a failed quantum computer.

Though not a quantum computer in the conventional sense, quantum mechanically non-local devices such as Buffy describes have such a long history in science fiction that, although impossible by all current theory, they have a conventional name: the ansible, a name credited to Ursula K Le Guin in 1966, but best known for the plot-central they play in Orson Scot Card’s 1977 ”Ender's Game and sequils.