  Quantum dot cellular automata (QCA) computing schemes use arrays of quantum
dots as computational devices. Typically, these operate ideally by maintaining
arrays in their ground state to ensure correct computational output. For large
QCA circuits, thermal fluctuations make this impossible, so adiabatic clocking
has been proposed as a means of dividing large circuit computations into
subcircuit computations that are more reliable. In this report, it is shown
that wires and inverters can transmit information correctly via their excited
states just as well as their ground states. A characteristic example of a 4
cell wire is simulated, and a theoretical derivation of this result is given.
When, non-nearest neighbor interactions are included in the Hamiltonian, this
result still holds true. On the other hand, QCA majority gates and more complex
circuits give incorrect results when operated in excited states. These results
suggest that gates of reliable QCA circuits should be contained in smaller
clocking zones, while wires relaying information can be contained in larger
clocking zones.
