Hewlett-Packard is betting that it can build computers whose functionality rests on the workings of individual molecules. It’s blue-sky research, but if it works, it will push computing far beyond the limits of silicon.

A chip in which silicon transistors are replaced with molecular devices could in principle be fabricated through a simple chemical process. A circuit with 10 billion switches could eventually fit on a grain of salt; that’s a thousand times the density of the transistors in today’s best computers. It might use nano imprint lithography, using a physical mold to create features as small as six nanometers across on silicon wafers. That’s more than an order of magnitude smaller than the finest features achievable using today’s advanced photo-lithographic processes.

Other alternatives to silicon include DNA computing, nanocells, nanotube electronic components, and quantum computing.