New Design of Efficient Reversible Quantum Saturation Adder

Reversible logic is becoming increasingly important with the rise of technologies like quantum computing, as it retains information during computation and maintains a one-to-one mapping between input and output patterns. Quantum circuits are inherently reversible and the best computational model in quantum computing systems. Some quantum signal processing applications like filters and image processing applications require the results of arithmetic operations to be saturated. Saturation occurs when adding two numbers with the same sign and this can be done through a quantum saturating adder. This paper proposed a reversible quantum saturating adder with efficient quantum criteria like quantum cost, number of ancilla, and number of garbage outputs. We firstly propose a reversible n-bit quantum saturation generator block which is applied to a quantum adder and construct a quantum saturating adder circuit. The proposed circuit is simulated using the Quirk online tool and the result confirms the accuracy of the design. This design achieves 18% and 33% improvement in quantum cost and garbage outputs, compared to its counterpart, respectively.