Asymptotically large-scale quantum computers
This is an attempt to formulate fundamental physical design principles for asymptotically large quantum computers and to characterize the physical systems that are suitable for asymptotically large quantum computers.
The basic argument is that near-critical physical systems are automatically protected by the renormalization group against almost all microscopic fluctuations. Only the fluctuations of the relevant and marginal couplings can affect the low energy quantum excitations. So near-critical systems are naturally suited for large-scale quantum computers.
As a practical matter, large quantum computers in the real 3-dimensional world will be constructed as large-scale quantum circuits. Therefore, the proposal is that large-scale quantum computers should be constructed as near-critical quantum circuits in universality classes described by 1+1 dimensional quantum field theories.
The fundamental physical design principles should be based on the Kirchhoff laws for entropy flow in such near-critical quantum circuits, which are derived in the two papers listed below.
Papers
- Entropy flow in near-critical quantum circuits (2005, revised 2017), arXiv:cond-mat/0505084v2
- Entropy flow through near-critical quantum junctions (2005, revised 2017), arXiv:cond-mat/0505085v2