USTC Jiuzhang 4.0 photonic quantum processor published in Nature; 3,050 photons, 10^54 speedup

University of Science and Technology of China (USTC)/Jiuzhang Photonic Quantum Processor

Chao-Yang Lu and Jian-Wei Pan's team at USTC published Jiuzhang 4.0 in Nature, the largest Gaussian boson sampling experiment to date. The programmable photonic processor encodes 1,024 squeezed-state inputs into an 8,176-mode hybrid spatial–temporal circuit and detects up to 3,050 photons per sample.

• Jiuzhang 4.0 detects 3,050 photons per run, over 12x the 255-photon maximum from Jiuzhang 3.0 in 2023.
• Achieves 92% light source efficiency and 51% overall system efficiency with 93%-efficient superconducting nanowire detectors.
• Spatial-temporal multiplexing via fiber delay loops accesses 8,176 effective modes using 16 physical detection channels.
• Solves Gaussian boson sampling in 25.6 microseconds, a speedup exceeding 10^54 compared to El Capitan supercomputer.