Optical Quantum Computing

TL;DR

This paper reviews the development of all-optical quantum computing, highlighting recent advancements that reduce resource requirements and discussing remaining challenges for scalable implementation.

Contribution

It summarizes recent progress in simplifying optical quantum computing architectures and identifies key technological challenges for large-scale realization.

Findings

Resource overhead has been significantly reduced with new approaches.

Recent demonstrations show practical feasibility of optical quantum computing.

Key technological challenges remain in photon sources, detectors, and optical circuits.

Abstract

In 2001 all-optical quantum computing became feasible with the discovery that scalable quantum computing is possible using only single photon sources, linear optical elements, and single photon detectors. Although it was in principle scalable, the massive resource overhead made the scheme practically daunting. However, several simplifications were followed by proof-of-principle demonstrations, and recent approaches based on cluster states or error encoding have dramatically reduced this worrying resource overhead, making an all-optical architecture a serious contender for the ultimate goal of a large-scale quantum computer. Key challenges will be the realization of high-efficiency sources of indistinguishable single photons, low-loss, scalable optical circuits, high efficiency single photon detectors, and low-loss interfacing of these components.