Cellular structures for computation in the quantum regime

We present a data-processing scheme, a hybrid of existing cellular automata (CA) and gate array architectures, which is optimized for realization at the quantum scale. For classical computing, our CA-like external clocking avoids problems associated with existing ground-state relaxation schemes. For quantum computing, our architecture constitutes a paradigm whereby the algorithm is embedded in spatial, as opposed to temporal, structure; we discuss the consequences for algorithmic efficiency. Two potential physical realizations of the scheme are discussed. [S1050-2947(99)04111-6].