Quantum Dot Cellular Automaton - Wire-crossing

Wire-crossing

Wire-crossing in QCA cells can be done by using two different quantum dot orientations (one at 45 degrees to the other) and allowing a wire composed of one type to pass perpendicularly "through" a wire of the other type, as shown schematically in figure 8. The distances between dots in both types of cells are exactly the same, producing the same Coulombic interactions between the electrons in each cell. Wires composed of these two cell types, however, are different: one type propagates polarization without change; the other reverses polarization from one adjacent cell to the next. The interaction between the different wire types at the point of crossing produces no net polarization change in either wire, thereby allowing the signals on both wires to be preserved.