[Cryptography] Quantum computers will never overcome noise issues?

[jamesd at echeque.com]

Any technology useful for processing information in the extreme quantum 
domain is also useful for doing classical extremely fast at extremely 
low energies, operating in the near quantum domain.  Since we are 
nowhere near the near quantum domain, hard to say what will happen when 
and if we get there.

We are currently stuck building circuits with 190 nanometer near UV 
light, which means that quantum effects are down deep in the noise.

What we would like to be able to do is to construct circuits out of 
nanoscale superconducting wires, superconducting wires that are in fact 
large molecules.  At that point, it would become more apparent what was 
feasible.

Any technology useful for implementing quantum computers, would also be 
useful for implementing classical computers at enormously greater speeds 
and lower energies than today's classical computers.

We need something better than 190 nanometer photolithography.