Nano Computers

Here's a date for your diary November 1st, 2011. According to a group of researchers calling themselves the Nanocomputer Dream Team, that's the day they'll unveil a revolutionary kind of computer, the most powerful ever seen. Their nanocomputer will be made out of atoms. First suggested by Richard Feynman in 1959, the idea of nanotechnology, constructing at the atomic level, is now a major research topic worldwide. Theoreticians have already come up with designs for simple mechanical structures like bearings, hinges, gears and pumps, each made from a few collections of atoms. These currently exist only as computer simulations, and the race is on to fabricate the designs and prove that they can work.



Moving individual atoms around at will sounds like fantasy, but it's already been demonstrated in the lab. In 1989, scientists at IBM used an electron microscope to shuffle 35 xenon atoms into the shape of their company's logo. Since then a team at IBM's Zurich labs has achieved the incredible feat of creating a working abacus on the atomic scale.
Each bead is a single molecule of buckminsterfullerene (a buckyball), comprising 60 atoms of carbon linked into a football shape. The beads slide up and down a copper plate, nudged by the tip of an electron microscope. The Nanocomputer Dream Team wants to use these techniques to build an atomic computer. Such a computer, they say can then be used to control simple molecular construction machines, which can then build more complex molecular devices, ultimately giving complete control of the molecular world.



The driving force behind the Dream Team is Bill Spence, publisher of Nanotechnology magazine. Spence is convinced that the technology can be made to work, and has enlisted the help of over 300 enthusiasts with diverse backgrounds - engineers, physicists, chemists, programmers and artificial intelligence researchers. The whole team has never met, and probably never will. They communicate by email and pool their ideas on the Web. There's only one problem. Nobody is quite sure how to build a digital nanocomputer.



The most promising idea is rod logic, invented by nanotechnology pioneer Eric Drexler, now chairman of the leading nano think tank The Foresight Institute. Rod logic uses stiff rods made from short chains of carbon atoms. Around each rod sits a knob made of a ring of atoms. The rods are fitted into an interlocking lattice, where each rod can slide between two positions, and be reset by a spring made of another few atoms. Drexler has shown how to use such an arrangement to achieve the effect of a conventional electronic transistor, where the flow of current in one wire is switched on and off by current in a different wire. Once you have transistors, you can build a NAND gate. From NAND gates you can construct every other logic element a computer needs.