When Harvard built the Mark I computer in 1944 to make calculations for the Air Force, it took minutes to do tasks that now take microseconds. Now, Harvard professors are working on conductors so small that electrons sometimes get stuck and bounce back.

Their research focuses on the use of nanowires and nanotubes to construct tiny electronic circuits. These wires and tubes, which can only be seen with the most powerful of microscopes, are so small that just moving them around is a challenge.

"It is a very important step towards building greater devices," says Phaedon Avouris, the manager of Nanometer Scale Science and Technology at IBM's Watson Research Center.

In a discovery that could radically change the way computers are made, Hyman Professor of Chemistry Charles M. Lieber says he has constructed working logic circuits, interconnecting transistors, with nanowires only ten atoms across.

The computer on your desk, by contrast, has wiring in the chips about 400 atoms wide.

Although members of Lieber's research group refuse to discuss the details of how they constructed these tiny circuits, such a discovery could lead to the development of ultra-small computers that consume very little power.

In a pair of papers published in Science magazine earlier this year, Lieber and his group showed how exceedingly small structures can be fabricated and arranged into circuits . This work then led to the group's most recent discovery.

"I am probably more excited than since I first came to Harvard when I was naïve and young," says Lieber.