The Nanomechanical Computer

eldavojohn writes "The BBC is reporting on a newly proposed type of nanomechanical computer that mimics J. H. Müller & Charles Babbage's work on mechanical computational devices — just on a much smaller scale. The paper is published today in the New Journal of Physics and cites three reasons to build a computer with nanomechanical transistors over bipolar-junction or field-effect transistors: '(i) mechanical elements are more robust to electromagnetic shocks than current dynamic random access memory based purely on complimentary metal oxide semiconductor technology, (ii) the power dissipated can be orders of magnitude below CMOS, and (iii) the operating temperature of such an NMC can be an order of magnitude above that of conventional CMOS.'"

Comments

Prior art...

[kebes]

This present design is a cool idea. I don't want to take anything away from the presented concept, but I thought it would be important to point out previous work on nanomechanical computers. First of all, Eric Drexler (the guy who popularized the term "nanotechnology" and who basically invented the field now known as molecular nanotechnology) has been advocating the concept of nanomechanical computers for many years now (they are described in his book Engines of Creation (1986) and detailed feasibility calculations, and rough schematics, are presented in his book Nanosystems (1992)). Drexler has been trying to get people on-board with his very foreward-looking ideas for nanotechnology: where nano-sized mechanical systems would be performing computation, and controlling chemical reactions with a precision that currently only biological systems can achieve. (It should be noted that current work in "nanotechnology" is hilariously primitive compared to what Drexler intended the term to describe.) Drexler's vision of nano-mechanical systems has been challenged by many people, most notably by Richard Smalley (the guy who discovered buckyballs).

Beyond Drexler's theoretical work, carbon nanotubes were demonstrated as nano-mechanical transistors in 2000. Basically, the nanotube was positioned over various electric pads. A current could be applied to mechanically deform the nanotube. The deformation was stable, and could be read-out by measuring current across the tube. Since the deformation was stable and reversible, the tubes could be used as persistent storage or as switching/logic elements. In fact, switching speeds of gigahertz were demonstrated. The vision was to have long nanotubes in a huge cross-bar architecture, leading to high-density persistent storage. As is often the case, scale-up was difficult.

This present work appears to pattern a nano-sized post between conducting pads (out of a gold/silicon layered system) , and to use that post as a single-electron transistor. The 'mechanical' part comes from mechanically coupling multiple pillars to use as a gain mechanism for a transistor. This is basically much closer to conventional micro-lithography, and as such, it should fit in with current lithographic infrastructure much more easily than the nanotube concept did.

Re:Prior art...

[erichill]

Folks in the nanotech crowd have been talking about clockwork computing from the get-go. Gears and rods and the like have a lot of advantages over electronics at molecular scales: atoms much smaller wavelengths than electrons thereby easier to localize. Also, to a first (and second) approximation, covalent bonds don't wear: undesired reactions are the issue, and not much of one in the mechanical phase of matter(*) envisioned by Drexler and company.
Having skimmed the article, I'm a bit unimpressed by the comparison to Babbage. While this looks like neat technology, it's NOT clockwork--it's electronic transistors with mechanical gates, as noted in the parent.

(*) Parts only touching where desired, vacuum elsewhere--remember, we're talking atomic scale here.

Re:You don't need our permission

[QuantumG]

Dude, this kind of speculative crap is published every 6 months. Going from theory to practice is the science and until they do any they're just masturbating in public.

Man Proposes, Mechanics Disposes

[Doc Ruby]

They're far from the first to propose nanomechanical computing machines like Babbage's original (and failed) machines. A mentor of mine explained to me in 1990 an idea of building nanoscale rod logic in orbit: microgravity, vacuum, solar power. And I don't think he was the first to think of it.

I'll be impressed when someone actually builds some. Or writes a lot more engaging science fiction than the BBC just published.

Shock and vibration

[flyingfsck]

If the Nikei stock exchange uses a mechanical computer, then an earthquake in Japan will really send a shudder through the financial markets...

Re:One thing though...

[wall0159]

I'm not a nano-technologist, but I'd doubt that macroscopic ideas of friction and wear would apply to nano-machines.

Re:You don't need our permission

[FasterthanaWatch]

This is like half science.. Must everyone be an experimentalist?

Re:You don't need our permission

[heinousjay]

"Propose to an Englishman any principle, or any instrument, however admirable, and you will observe that the whole effort of the English mind is directed to find a difficulty, a defect, or an impossibility in it. If you speak to him of a machine for peeling a potato, he will pronounce it impossible: if you peel a potato with it before his eyes, he will declare it useless, because it will not slice a pineapple."

- Charles Babbage