The superconducting quantum supremacy demonstrations serve as crucial milestones on the path to full-scale quantum computation. ![]() In these examples, comparison of the duration of the quantum sampling experiment to the estimated runtime and scaling of the best-known classical algorithms placed their respective platforms within the regime of quantum computational advantage. Both were shortly followed by larger versions, respectively enjoying more qubits 7, 8 and increased control over brightness and a limited set of circuit parameters 2. One such demonstration relied on a 53-qubit programmable superconducting processor 6, whereas another used a non-programmable photonic platform implementing Gaussian boson sampling (GBS) with 50 squeezed states fed into a static random 100-mode interferometer 1. In all of these, the computational task involved sampling from probability distributions that are widely believed to be exponentially hard to simulate using classical computation. Only a handful of experiments have used quantum devices to carry out computational tasks that are outside the reach of present-day classical computers 1, 2, 6, 7. This work is a critical milestone on the path to a practical quantum computer, validating key technological features of photonics as a platform for this goal. Ours constitutes a very large GBS experiment, registering events with up to 219 photons and a mean photon number of 125. This runtime advantage is over 50 million times as extreme as that reported from earlier photonic machines. On average, it would take more than 9,000 years for the best available algorithms and supercomputers to produce, using exact methods, a single sample from the programmed distribution, whereas Borealis requires only 36 μs. We carry out Gaussian boson sampling 4 (GBS) on 216 squeezed modes entangled with three-dimensional connectivity 5, using a time-multiplexed and photon-number-resolving architecture. Here we report quantum computational advantage using Borealis, a photonic processor offering dynamic programmability on all gates implemented. ![]() ![]() Earlier photonic demonstrations were also vulnerable to spoofing 3, in which classical heuristics produce samples, without direct simulation, lying closer to the ideal distribution than do samples from the quantum hardware. No photonic machine offering programmability over all its quantum gates has demonstrated quantum computational advantage: previous machines 1, 2 were largely restricted to static gate sequences. A quantum computer attains computational advantage when outperforming the best classical computers running the best-known algorithms on well-defined tasks.
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