Efficient design of quaternary quantum comparator with only a single ancillary input

Abstract

Circuit design with no energy dissipation is possible in the reversible logic. Also, using the quantum multiple-valued logic in the design of circuits due to the reduction of circuit width leads to the smaller chip area and lower power consumption. Quaternary reversible logic potentially has several advantages in comparison to the equivalent ternary and binary quantum technologies. Hence, the quaternary quantum technology is a promising choice for the future digital system design. Here, the authors proposed an efficient design of 1-qudit and n-qudit quantum comparators. The comparator module is widely used in search conditions, such as Grover's quantum search algorithm in quantum computing. The proposed circuits were better than their existing counterparts in terms of quantum cost, the number of constant inputs, the number of garbage outputs, and hardware complexity. To design these circuits, they have used 1-qudit gates and 2-qudit Muthukrishnan-Stroud gates. The efficiency of their proposed circuits was reported.