Quantum-dot Cellular Automata (QCA) are digital computing machines based on electrostatic and quantum effects. Their basic unit, the cell, is a bistable memory element containing mobile charges. Computation ensues from electrostatic interaction among neighboring cells. QCA are conceived to be implemented at the nanoscale: molecular-scale cells, in particular, would make them operable at ambient temperature. Designing suitable molecular unit is then common ground for chemists and computer scientists, and a shaky one. The classical QCA paradigm, in fact, imposes many, often implicit but severe constraints on the geometry and energy behavior of cells, not easily fulfilled by realistic systems. Here, a general model is developed to include the several symmetrybreaking characteristics of real-world molecules. The consequences of such non-idealities on the computational behavior of molecular QCA are investigated. Some are found very critical to computation; some other configurations, however apparently odd, might surprisingly prove of some usefulness. Anyway, future chemical design of suitable QCA molecular units cannot neglect these findings.
Quantum-dot Cellular Automata: Computation with Real-World Molecules
Rinaldi R
2015
Abstract
Quantum-dot Cellular Automata (QCA) are digital computing machines based on electrostatic and quantum effects. Their basic unit, the cell, is a bistable memory element containing mobile charges. Computation ensues from electrostatic interaction among neighboring cells. QCA are conceived to be implemented at the nanoscale: molecular-scale cells, in particular, would make them operable at ambient temperature. Designing suitable molecular unit is then common ground for chemists and computer scientists, and a shaky one. The classical QCA paradigm, in fact, imposes many, often implicit but severe constraints on the geometry and energy behavior of cells, not easily fulfilled by realistic systems. Here, a general model is developed to include the several symmetrybreaking characteristics of real-world molecules. The consequences of such non-idealities on the computational behavior of molecular QCA are investigated. Some are found very critical to computation; some other configurations, however apparently odd, might surprisingly prove of some usefulness. Anyway, future chemical design of suitable QCA molecular units cannot neglect these findings.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.