Chinese researchers have unveiled Jiuzhang 4.0, a photonic quantum computer that solved a benchmark problem far faster than the world's most powerful classical supercomputer. The machine completed the Boson sampling task — a test of quantum advantage — in mere seconds, while the fastest classical system would have taken thousands of years. The result marks a significant leap in photonic quantum computing and solidifies China's position at the forefront of the field.
What Boson sampling means
Boson sampling is a specially designed problem that simulates the behavior of indistinguishable photons passing through a network. It is extremely hard for classical computers because the number of possible outcomes grows exponentially with the number of photons. But quantum computers, which use photons themselves, can naturally handle the calculation. Jiuzhang 4.0 uses a setup of photonic circuits and detectors to run the sampling directly, bypassing the need for a classical simulation.
How fast is it?
The team behind Jiuzhang 4.0 reported that the quantum computer solved the Boson sampling problem in a fraction of a second. In contrast, the most advanced classical supercomputer of 2025 would require an estimated 10,000 years to complete the same calculation. That kind of speedup — many orders of magnitude — is what researchers call quantum supremacy, though the term is debated because the problem is tailored for quantum systems.
Why photonic quantum computing matters
Most quantum computers today rely on superconducting circuits, trapped ions, or other solid-state platforms. Photonic quantum computers use light particles, which are easy to manipulate and move at high speeds. They also operate at room temperature, avoiding the extreme cooling that superconductors require. However, photonic systems have historically struggled with scaling up the number of photons and maintaining low error rates. Jiuzhang 4.0 appears to have overcome some of those hurdles, at least for Boson sampling.
China's lead in photonic quantum computing
Jiuzhang 4.0 is the latest in a series of photonic quantum computers developed by Chinese researchers. Earlier versions — Jiuzhang 1.0, 2.0, and 3.0 — each set records for photon count and speed. The 4.0 version cements China's dominance in this particular approach. The achievement comes as countries like the United States, Canada, and the United Kingdom pour resources into competing quantum technologies, but none have yet matched this performance in the Boson sampling task.
The challenge now is to move Jiuzhang 4.0 beyond benchmark problems toward real-world applications, such as quantum simulation for chemistry or materials science. Researchers will need to demonstrate that photonic quantum computers can solve useful problems that classical machines cannot, not just specialized tests. The team behind Jiuzhang is expected to publish a detailed paper in a peer-reviewed journal in the coming months, which will allow independent verification of the results.
