  Interactions of quantum cellular automata (QCA) circuits with their
environment induce transitions in their quantum states that can cause errors in
computation. The nature of these interactions depend on the specific physical
implementation of the circuit. In the case of silicon dangling bond QCA, one
channel of environmental interaction is between dangling bond cells and
longitudinal phonons in the silicon lattice. In the presence of this
environmental interaction, short 4 cell wire simulations show reliable
operation at liquid nitrogen temperature, however simulation and theoretical
arguments suggest long wires operated from thermal equilibrium are susceptible
to exponential decay of cell polarization along their length regardless of
clock zoning. Quantum annealing is suggested as a technique for bringing QCA
wires into their ground state prior to information transmission to circumvent
this problem.
