Overview
- The USTC team led by Pan Jianwei reported in Nature that Jiuzhang 4.0 finished a Gaussian boson sampling run in 25 microseconds, compared with their estimate of 10^42 years for the El Capitan supercomputer.
- Gaussian boson sampling is a benchmark that draws patterns from many photons and is designed to be extremely hard for classical machines.
- The photonic device routes squeezed light through an 8,176‑mode interferometer with 1,024 inputs and detects up to 3,050 photons, a scale jump of more than tenfold over earlier experiments.
- The team reported about 92% source efficiency and 51% overall efficiency, which addresses photon loss that has long limited photonic quantum hardware.
- USTC frames the result as quantum supremacy for this single task, while coverage notes it is not a fault‑tolerant, general‑purpose computer and contrasts China’s photonic path with US work on superconducting qubits.