Physics

Mathematics

Algorithm

Optics

Statistical physics

Limit (mathematics)

Mathematical analysis

Sampling (signal processing)

Photon

Interferometry

Scale (ratio)

Computer science

Quantum mechanics

Boson

Detector

Physical Review Letters

Quantum computing experiments are moving into a new realm of increasing size and complexity, with the short-term goal of demonstrating an advantage over classical computers. Boson sampling is a promising platform for such a goal; however, the number of detected single photons is up to five so far, limiting these small-scale implementations to a proof-of-principle stage. Here, we develop solid-state sources of highly efficient, pure, and indistinguishable single photons and 3D integration of ultralow-loss optical circuits. We perform experiments with 20 pure single photons fed into a 60-mode interferometer. In the output, we detect up to 14 photons and sample over Hilbert spaces with a size up to 3.7×10^{14}, over 10 orders of magnitude larger than all previous experiments, which for the first time enters into a genuine sampling regime where it becomes impossible to exhaust all possible output combinations. The results are validated against distinguishable samplers and uniform samplers with a confidence level of 99.9%.

Boson Sampling with 20 Input Photons and a 60-Mode Interferometer in a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>1</mml:mn><mml:msup><mml:mn>0</mml:mn><mml:mn>14</mml:mn></mml:msup></mml:math>-Dimensional Hilbert Space

Boson Sampling with 20 Input Photons and a 60-Mode Interferometer in a1014-Dimensional Hilbert Space