Difference between revisions of "Non mechanical technology path"

Revision as of 17:02, 21 April 2014

In advanced nanofactories electric systems will probably be used. Electric systems though can't yet be integrated into plans for nanofactories because of a lack of a set of well understood near ideal components. (For more information see: Nanosystems Section 1.3.4.b No nanoelectronic devices.) Please keep discussions about the application of electric systems for nanofactories on this page until this restriction is lifted.

Applications depending on non mechanical base technologies can be fond at at the "most speculative potential applications" page.

Diffeculties

Molecular electronics in technology level I behave rather non digital (neither diode nor resistor behavior)

In small (or big and very cold) AP repetitive structures electrons move as Bloch-waves without being scattered. One also speaks of ballistic electron movement because in the wave picture (sharp impulse, infinitely long wave in space) the electrons move like billiard balls. Electrons can become problems flowing around sharp conductor bends since they do not collide with each other but only with the conductors walls. This is essentially the same effect as the limited gas conduction due to the free molecular flow in vacuum systems. At higher temperatures the unavoidable electron phonon scattering becomes stronger [Todo: check how much electrons can easier flow around bends then] Very small conductors can constrain electrons so much that the electron wave function loose all their nodes in the directions normal to the conductor surfaces (lowest mode excitation - similar to the situation in an optical single mode wave guide) This situation is called low dimensional electron gas [Todo: check wether tighter bends can be made in this case?]

Some kinds of electronics

Restricting oneself to pure hydrocarbons like the "direct approach" motivates one can use graphene ribbons, nanotubes or other graphitic/polyaromatic structures like graphene ribbons as conductors and semiconductors and vacuum (,air) or diamond as isolator.

Note that while pyrolythic graphite is a resistive material nanotubes can conduct current between one and two orders of magnitude better than copper. Electronic properties may be heavily influenced by:

• Statically included (or dynamically applicable) high mechanical strain
• the borders of the graphitic structure - closed, hydrogen terminated, chucked between two slabs of diamond

electric contacts between parts moving relative to one another can be either made flexible for reciprocative movement or via tunneling between two combs of graphitic sheets. For low resistance the contacts need to be way bigger than the conductors [Todo:quantify]

If one allows some nonmetals one can create diamond checkerboard doped with nitrogen very similar to todays nanoelectronics.

Magnetism

Magnetisms plays little role in nanofactories. Scaling laws make electrostatic motors and generators preferrable.

Magnetism could be needed for ĺevitation of macroscopic objects like in a thermal vacuum isolation vessel (dewar).

Carbon atoms have long been thought to be completely non-magnetic. It has been found that specific radical structures can exhibit strong magnetism [Todo: verify, check which structures, note which kind of magnetism and how strong]

Spin flips in tooltips can be influenced by nearby massive atoms with high spin orbit coupling (Nanosystems 8.4.3.b Radical coupling and inter system crossing) this has some relevance for mechanosynthesis.

Other

High temperature superconductivity is not yet clearly understood and subject of research. AP technology will probably make this research easier.

Photochemistry is rather non-local (big optical wavelength of UV light) and thus not of central importance for mechanosynthesis. See Nanosystems 8.3.3.d. Localized electrochemistry, "photochemistry."

Quantum computation

Quantum computation is obviously not a necessity for APM systems. APM systems and quantum computers may mutually boost each other though.

• It's very questionable whether pure hydrocarbon quantum computers can be built.
  Nitrogen vacancy centers are currently (2014) investigated and will with APM systems be distributable to exact atomic locations.
• Searching for an optimal configuration of system components in a nanofactory relative to some chosen metric (playing a puzzle game) is essentially a search problem on which grovers algorithm could be applied always providing a quadratic speedup. Special cases may be exponentially accellerable. While probably looking like a great artwork the downside is that those found solutions are something like "convoluted projection from some high dimensional space, or the result of an execution of some dubious program" where one can not understand how the solution was found just by looking at it and even hardly by in depth analysis.

Like heat dissipation free computation quantum computation needs reversible data processing as prerequisite.