The Feynmann processor: an introduction to quantum computation by Gerard Milburn. Like (I expect) most of us, I’ve never understood anything about quantum computation and have been vaguely suspicious that the whole project involves some kind of spurious informational free lunch. On the other hand, having read Feynmann’s excellent QED, I’m reasonably comfortable with the basic ideas of quantum electrodynamics (though I’ve never got on top of the nasty integrals required to actually work anything out). Feynmann’s discussion in terms of probabilty amplitudes steers clear of all that Heisenberg-style mysticism that seems to make the whole subject incomprehensible.
Anyway, this post by John Holbo at CT, and particularly this comment, led me to a Wikipedia article which made it clear how you quantum processing could yield impressive gains without any magical mumbo-jumbo, so I went on to look for more, and found this book in the library. It’s very easy going for a general reader, and makes things pretty clear, though I took a couple of readings to get the details straight.
As it happens, Gerard is at UQ and got a Federation Fellowship at the same time I did, so I’ll probably be pestering him for more info on all this.