Konrad Kieling, David Gross, and Jens Eisert
Several physical architectures allow for the sequential preparation of cluster states for measurement-based quantum computing using probabilistic quantum gates. In such an approach, the order in which partial resources are combined to form the final cluster state turns out to be crucially important. We determine the influence of this classical decision process on the expected size of the final cluster. Extending earlier work, we consider different quantum gates operating at various probabilites of success. For finite resources, we employ a computer algebra system to obtain the provably optimal classical control strategy and derive symbolic results for the expected final size of the cluster. Surprisingly, two substantially different regimes can be identified: When the success probability of the elementary gates is high, the influence of the classical control strategy is found to vanish. In that case, other figures of merit become more relevant. For small probabilities of success, the choice of an appropriate strategy is crucial.
In New J. Phys.