This paper presents the design and simulation of two key quantum arithmetic circuits—Ripple Carry Adder (RCA) and Carry Look-Ahead Adder (CLA)—using IBM's Qiskit framework. By translating classical adder logic into reversible quantum gates such as CNOT and Toffoli (CCNOT), the RCA employs sequential carry propagation for simplicity but incurs linear depth scaling, while the CLA leverages parallel propagate and generate signals to achieve reduced circuit depth and enhanced speed. Simulations on Qiskit's qasm_simulator backend validate functionality, highlight trade-offs in gate count, complexity, and scalability, and demonstrate quantum parallelism via superposition and entanglement. Results underscore CLA's superiority for large-scale applications, with future directions including optimization for NISQ hardware and error correction.
Keywords : Quantum Computing, Ripple Carry Adder, Carry Look-Ahead Adder, Qiskit, Reversible Logic, Arithmetic Circuits.
Author : Dr P Dhana Lakshmi, Dr N Venkateswara Rao and G sandhya
Title : Quantum Arithmetic Circuits: Design and Simulation of Ripple Carry and Carry-Look Ahead Adders using Qiskit
Volume/Issue : 2025;02(07)
Page No : 1-9
