author : Wil McCarthy

Quantum dots are nanoscale regions, manufacturable with fairly conventional solid state technology, where electrons can be confined to behave like "artificial atoms". McCarthy takes us on a tour of the fascinating physics behind these dots, and some of the wondrous things such artificial atoms could do. Matter containing arrays of such dots could have seemingly magical properties. Moreover, using technology similar to that used to control computer circuits today, the properties of the electron confinement (and hence of the artificial atoms) can be altered, so these properties could be programmable. Matter could change its transparency, thermal and electrical conductivity, stiffness, colour, texture, whatever, effectively instantaneously.

To start with, McCarthy describes the physics behind all this. It's quite deep, and I'm not sure how comprehensible to someone without quite a lot of the background already. But it's clearly explained, with little vignettes from the scientists involved that enliven, but do not overshadow, the technical concepts.

Then McCarthy goes on to explain the consequences of having such programmable matter -- programmable quantum dots woven into a silicon substrate, in a material he calls "Wellstone". Applications range from building materials, transport, smart clothing, to medical. I found this section rather disappointing, after all the early hype, for main two reasons. Firstly, he only talks about end products, with no feel for how you would go about constructing with this material -- can you work it like wood or cloth to build your own smart house or sew your own smart coat? Or are the building and clothing industries of the future going to require fleets of hardware engineers connecting and configuring the dots? And secondly, the applications covered seem a little ... tame. Most seems to be on better heat management in buildings. (All in all, this section felt a little rushed. He has an SF novel, The Wellstone, which he says explores this in more detail: I'll be reading soon, to find out some more applications for this material.)

The subtitle is rather a misnomer, too -- the small section on levitation discusses cars, trains, frogs, and people -- not chairs -- and quantum mirages are covered in a scant few sentences. However, the ideas here, no matter how briefly described, are mind-boggling enough, and so very close on the horizon, that anyone with an interest in just how magical advanced technology can look should read it.