Distributed Quantum Computing: a Survey

TL;DR

This survey reviews the current state and challenges of distributed quantum computing, emphasizing its potential to scale quantum processors beyond current limitations by enabling multiple quantum devices to cooperate.

Contribution

It provides a comprehensive overview of the main challenges, open problems, and relevant literature in distributed quantum computing from an engineering perspective.

Findings

Distributed quantum computing is key to scaling qubit numbers.

Major challenges include communication, synchronization, and error management.

Open problems involve hardware integration and protocol development.

Abstract

Nowadays, quantum computing has reached the engineering phase, with fully-functional quantum processors integrating hundred of noisy qubits available. Yet -- to fully unveil the potential of quantum computing out of the labs and into business reality -- the challenge ahead is to substantially scale the qubit number, reaching orders of magnitude exceeding the thousands (if not millions) of noise-free qubits. To this aim, there exists a broad consensus among both academic and industry communities about considering the distributed computing paradigm as the key solution for achieving such a scaling, by envision multiple moderate-to-small-scale quantum processors communicating and cooperating to execute computational tasks exceeding the computational resources available within a single processing device. The aim of this survey is to provide the reader with an overview about the main challenges and open problems arising with distributed quantum computing, and with an easy access and guide towards the relevant literature and the prominent results from a computer/communications engineering perspective.