Quantum cellular automata

TLDR

The authors introduce quantum cellular automata as a new paradigm for computing with arrays of quantum devices and propose a specific realization using two‑electron quantum‑dot cells. Computing is edge‑driven, with input, output, and power supplied only at the array boundary, and the ground‑state configuration of the quantum‑dot cells—determined by boundary conditions—produces the result, while cell polarization induces nonlinear Coulomb coupling to neighboring cells. The highly polarized charge density in the two‑electron cells demonstrates a two‑state CA, and the authors construct AND, OR, and inverter gates, showing that quantum cellular automata can perform useful computing.

Abstract

The authors 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. The authors propose a specific realization of these ideas using two-electron cells composed of quantum dots. 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. The authors show that AND gates, OR gates, and inverters can be constructed and interconnected.