Analyzing Quantum Circuit Depth Reduction with Ancilla Qubits in MCX Gates

TL;DR

This paper reviews techniques for reducing the depth of multi-controlled X (MCX) gates using ancilla qubits, analyzing their performance across various quantum topologies, with a focus on practical implementation in quantum computing libraries.

Contribution

It provides a high-level overview and comparison of MCX depth reduction methods like recursion and v-chain, tailored for non-expert readers.

Findings

Recursion and v-chain are the most common MCX reduction techniques.

Performance varies depending on quantum topological settings.

The paper offers insights into practical implementation in Qiskit.

Abstract

This paper aims to give readers a high-level overview of the different MCX depth reduction techniques that utilize ancilla qubits. We also exhibit a brief analysis of how they would perform under different quantum topological settings. The techniques examined are recursion and v-chain, as they are the most commonly used techniques in the most popular quantum computing libraries, Qiskit. The target audience of this paper is people who do not have intricate mathematical or physics knowledge related to quantum computing.