Quantum circuits with many photons on a programmable nanophotonic chip

TL;DR

This paper presents a fully integrated, programmable nanophotonic chip capable of executing complex many-photon quantum circuits at room temperature, enabling advanced quantum algorithms and surpassing previous optical demonstrations.

Contribution

It introduces a complete hardware-software platform for many-photon quantum computing with high photon numbers, programmable interferometers, and photon-resolving detection on a scalable chip.

Findings

Achieved multi-photon detection with record photon numbers and rates.

Verified non-classical output states.

Demonstrated three quantum algorithms: Gaussian boson sampling, molecular vibronic spectra, and graph similarity.

Abstract

Growing interest in quantum computing for practical applications has led to a surge in the availability of programmable machines for executing quantum algorithms. Present day photonic quantum computers have been limited either to non-deterministic operation, low photon numbers and rates, or fixed random gate sequences. Here we introduce a full-stack hardware-software system for executing many-photon quantum circuits using integrated nanophotonics: a programmable chip, operating at room temperature and interfaced with a fully automated control system. It enables remote users to execute quantum algorithms requiring up to eight modes of strongly squeezed vacuum initialized as two-mode squeezed states in single temporal modes, a fully general and programmable four-mode interferometer, and genuine photon number-resolving readout on all outputs. Multi-photon detection events with photon numbers and rates exceeding any previous quantum optical demonstration on a programmable device are made possible by strong squeezing and high sampling rates. We verify the non-classicality of the device output, and use the platform to carry out proof-of-principle demonstrations of three quantum algorithms: Gaussian boson sampling, molecular vibronic spectra, and graph similarity.