Читать книгу Reversible and DNA Computing - Hafiz M. H. Babu - Страница 27

The quantum realization of reversible Fredkin (FRG) gate is shown in Figure 1.4. Each quantum Ex‐OR gate and quantum or gate requires 1 (one) quantum cost. The reversible FRG gate has four quantum Ex‐OR gates, two quantum V gates, and one quantum gate. So, the quantum cost of reversible FRG gate seems 7 (seven). But, we know if a quantum Ex‐OR gate and a quantum or gate exist angularly (denoted by angular box), then the quantum cost is treated as 1. From the figure, we see that there exists two angular boxes, and each angular box is treated as 1 quantum cost. As a result, the total quantum cost of reversible FRG gate is 5 (five).

Figure 1.4 Quantum realization of reversible Fredkin (FRG) gate.