Proposed 'Nanomechanical' Computer is Both Old-School and Cutting-Edge

August 3rd, 2007 by Laura Mgrdichian

A group of engineers have proposed a novel approach to computing: computers made of billionth-of-a-meter-sized mechanical elements. Their idea combines the modern field of nanoscience with the mechanical engineering principles used to design the earliest computers.

In a recent paper in the New Journal of Physics, the researchers, from the University of Wisconsin-Madison (UWM), describe how such a nanomechanical computer could be designed, built, and put to use.

Their work is a contemporary take on one of the very first computer designs: the “difference engine,” a 15-ton, eight-foot-high mechanical calculator designed by English mathematician and engineer Charles Babbage beginning in 1822. Corresponding UWM scientist Robert Blick said that he was also inspired by the design of a small hand-cranked mechanical calculator invented and sold in the 1950s, the Curta.

The computer they envision could never be as fast as traditional semiconductor-based computers, where individual transistors can operate at 100 gigahertz (GHz). However, Blick told PhysOrg.com, “We designed the circuits in this nanomechanical computer with the idea in mind that, at the nanoscale, mechanical motion is quite fast – 100 megahertz to a few gigahertz. This should make them competitive with existing micro-processors, which are used in a variety of mundane applications.”

Among these applications are appliances, electronic toys, and automobiles, all which contain basic computers in order to function but don't require ultra-fast processors.

The design's basic unit is the “nanomechanical single-electron transistor,” or NEMSET, a tiny circuit component that combines a typical silicon transistor with a nanoscale mechanical switch – a tiny moving part. A full circuit composed of multiple NEMSETs could be created, the researchers say, using one step of photolithography and one step of etching, methods commonly used to create silicon-based circuits.

The nanomechanical computer has three main advantages compared to semiconductor-based computers. It is more resilient to electric shock, its circuits can operate at significantly higher temperatures (several hundred degrees Celsius), and it is much more energy efficient, dissipating a fraction of the energy of traditional computers.

Additionally, the computer's memory structure may have an edge over standard memory. A nanomechanical form of memory may not need to be restricted to the “1” and “0” states that a typical computer uses to store a single bit (the most basic unit of information; these values correspond to a memory cell that is either charged or uncharged). A nanomechanical system could have several stable states, allowing for more efficient data storage.

Citation: Robert H Blick, Hua Qin, Hyun-Seok Kim and Robert Marsland, “A nanomechanical computer—exploring new avenues of computing” New Journal of Physics 9 (2007) 241.

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