Semiclassical simulation of quantum cellular automaton circuits

We present a simulator for quantum cellular automaton (QCA) circuits, based on a semiclassical model and aimed at the determination of the error probability in the presence of thermal excitations. Different methods are discussed; either a complete exploration of the configuration space, or a partial exploration by means of simulated annealing. Results for the probability of obtaining the ground state and the correct logical output are derived and compared for a chain of cells, for a majority voting gate and for a simple combinatorial network. This approach can be extended to generic implementations of the QCA paradigm. Copyright (C) 2001 John Wiley & Sons, Ltd.