Design and Analysis of Quantum Binary Adder-Subtractor Using IBM Qiskit

In this paper, an n-bit Quantum Binary Adder-Subtractor (QBAS) is designed using quantum logic gates using IBM Qiskit. A comprehensive understanding of the principles of quantum computing and quantum logic gates is also provided. As the fundamental module of a binary adder-subtractor circuit is a full adder, various designs of quantum full adders (QFAs) from the literature are investigated on various aspects to deliberately choose the best quantum full adder suitable for QBAS application. A QBAS circuit is thus designed using the selected QFA, analyzed and tested for its ability to replicate the output of its classical counterpart. The results obtained here will aid researchers in the design of Quantum Arithmetic Logic Units (QALUs), Quantum multipliers, dividers, and other scalable adder circuits. The proposed circuits and its results shown here expected to pave the way for design of compact and state of the art quantum adders with reduced number of qubits, quantum cost.