Generation and sampling of quantum states of light in a silicon chip

Implementing large instances of quantum algorithms^1–5 requires the processing of many quantum information carriers in a hardware platform that supports the integration of different components⁶. Although established semiconductor fabrication processes can integrate many photonic components⁷, the generation and algorithmic processing of many photons has been a bottleneck in integrated photonics. Here, we report the on-chip generation and algorithmic processing of quantum states of light with up to eight photons. Switching between different optical pumping regimes, we implement the scattershot^8,9, Gaussian¹⁰ and standard boson sampling^3,11–14 protocols in the same silicon chip, which integrates linear and nonlinear photonic circuitry. We use these results to benchmark a quantum algorithm for calculating molecular vibronic spectra⁴. Our techniques can be readily scaled for the on-chip implementation of specialized quantum algorithms with tens of photons, pointing the way to efficiency advantages over conventional computers¹⁵.