A Feasible Design of Elementary Quantum Arithmetic Logic Units for Near-Term Quantum Computers

TL;DR

This paper presents practical designs for quantum arithmetic units suitable for near-term quantum computers with limited qubit connectivity, enabling scalable quantum computations.

Contribution

It introduces feasible quantum arithmetic units using only local gates for near-term quantum computers with 2D qubit arrays.

Findings

Designs for quantum adders, subtractors, multipliers, dividers

Implementation using only local gates (Pauli-X, CNOT, CSX)

Supports two's complement computation for signed integers

Abstract

Quantum arithmetic logic units (QALUs) constitute a fundamental component of quantum computing. However, the implementation of QALUs on near-term quantum computers remains a substantial challenge, largely due to the limited connectivity of qubits. In this paper, we propose feasible QALUs, including quantum binary adders, subtractors, multipliers, and dividers, which are designed for near-term quantum computers with qubits arranged in two-dimensional arrays. Additionally, we introduce a feasible quantum arithmetic operation to compute the two's complement representation of signed integers. The proposed QALUs utilize only Pauli-X gates, CNOT gates, and $C\sqrt{X}$ (CSX) gates, and all two-qubit gates are operated between nearest neighbor qubits. Our work demonstrates a viable implementation of QALUs on near-term quantum computers, advancing towards scalable and resource-efficient quantum arithmetic operations.