Quantum cellular automata

• Published in: Nanotechnology Vol. 4; no. 1; pp. 49 - 57
• Main Authors: Lent, C S, Tougaw, P D, Porod, W, Bernstein, G H
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.1993; Institute of Physics
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Integrated circuits; Integrated circuits by function (including memories and processors); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Inverting device; Cellular automaton; Nanosecond; Logic array; Integrated circuit; Quantum effect; Modeling
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/4/1/004

We formulate a new paradigm for computing with cellular automata (CAS) composed of arrays of quantum devices - quantum cellular automata. Computing in such a paradigm is edge driven. Input, output, and power are delivered at the edge of the CA array only, no direct flow of information or energy to internal cells is required. Computing in this paradigm is also computing with the ground state. The architecture is so designed that the ground-state configuration of the array, subject to boundary conditions determined by the input, yields the computational result. We propose a specific realization of these ideas using two-electron cells composed of quantum dots, which is within the reach of current fabrication technology. The charge density in the cell is very highly polarized (aligned) along one of the two cell axes, suggestive of a two-state CA. The polarization of one cell induces a polarization in a neighboring cell through the Coulomb interaction in a very non-linear fashion. Quantum cellular automata can perform useful computing. We show that AND gates, OR gates, and inverters can be constructed and interconnected.