Quantum light computer breaks speed record

Chinese scientists have unveiled a new version of a quantum computer that has set a new world record for optical quantum information technology, that is, technology based on light.

Hua-Liang Liu and colleagues at the University of Science and Technology of China (USTC) used a photonic quantum computer to solve a Gaussian boson sampling problem at a speed more than 10 ^⁵⁴ times faster than the world’s most powerful supercomputer is capable of.

It’s an almost unthinkable advantage: If a quantum computer were set to perform a calculation lasting one hour, an electronic supercomputer would need the equivalent of about 839 ^times the age of the Universe to solve the same calculation.

This was possible because this new version of the machine, named Jiuzhang 4.0, can manipulate and detect quantum states of up to 3,050 photonic qubits, a significant leap compared to the 255 photons manipulated by Jiuzhang 3.0.

This is a major step forward in the scale and complexity of photonic quantum processors, but the team wants much more, already talking about building three-dimensional photonic qubit systems, potentially reaching trillions of qubits.

“This means that the most complex data sample generated by Jiuzhang 4.0 takes only 25 microseconds to produce – less time than a blink of an eye. In contrast, the world’s most powerful supercomputer would need more than 10 to the power of 42 years to calculate the same result,” said Professor Lu Chaoyang.

Principle of the space-time hybrid coding circuit used by the photonic processor.
[Image: Hua-Liang Liu et al. – 10.1038/s41586-026-10523-6]

Photonic quantum computer

The main technological routes of quantum computing currently utilize qubits from superconducting systems, ion traps, neutral atoms, and photons.

The Jiuzhang series of prototypes encodes quantum bits using photons, having debuted in 2020 and propelled quantum supremacy .

Since then, the machine has undergone several upgrades, reaching new levels of quantum computing advantage and setting new records. Quantum supremacy is the point at which quantum processors definitively surpass classical electronic processors , solving problems that would be impossible to solve with electronics-based technology in a reasonable amount of time.

Although the record is in comparison to a traditional electronic supercomputer, it is important to highlight that the Gaussian boson sampling technique involves a type of processor designed for this specific type of calculation, capable of solving only this type of problem. A classical supercomputer, on the other hand, can be programmed to solve any type of problem. In other words, Jiuzhang is not a “universal” processor.