China overtakes Google and creates quantum computer a billion times faster

A Chinese company developed a revolutionary computer, based on particles of light, which was able to do, in less than three minutes, calculations considered impossible for a normal computer.

The new computer, based on quantum photon technology, which deals with particles of light, or photons, achieved what was conventionally known as quantum supremacy, something that had already been achieved once, in 2019, with a quantum computer from Google, but it used a different technology.

Named Jiuzhang, in reference to an ancient Chinese mathematical text, this new computer took about three minutes to do a calculation that would take more than half a million years on the fastest existing supercomputer.

“This is the first independent confirmation of Google’s claim that it is possible to achieve quantum supremacy,” commented theoretical computer scientist Scott Aaronson of the University of Texas in Austin, USA, in a statement to “Science” magazine, which advanced the news.

Google’s quantum computer, Sycamore, is based on tiny quantum particles made of superconducting materials, which carry energy without resistance. Jiuzhang, on the other hand, is formed by a complex set of optical devices, which shoot photons. These devices include light sources, hundreds of ray separators, dozens of mirrors and 100 photon detectors.

This technology, known as Gaussian boson sampling (GBS, in its original acronym), calculates the output of a beam of light with numerous inputs and outputs. In the computer built by the Chinese, the photons are sent simultaneously by a circuit, a process known as quantum overlay. The photons are divided by the ray separators and continue on the circuit finding mirrors and more photon separators.

The paths also merge and it is the repeated division and fusion that causes photons to interfere with each other, according to quantum laws. If two photons found the same separator at the same time, they will follow, indivisibly, a path away from the separator. The process is repeated, resulting in a distribution of numbers that represents the capacity of the network.

In this way, Jiuzhang can reach a GBS 100 billion times faster than the fastest supercomputer currently in the world.

This type of quantum computer has a limitation, since it can only do these types of tasks, Gaussian boson sampling, while Google’s computer can be programmed to execute a wide variety of algorithms.

There are, however, other models of quantum computers under development, which are programmable. Some to be developed by a Canadian company, Xanadu, based in Toronto, and which now sees a ray of light on the horizon for this technology.

Demonstrating quantum supremacy with two different types of computers, Jiuzhang and Sycamore, shows the advance of quantum computing. “This shows that this area is developing in a very mature way,” noted Fabio Sciarrino, from the University of Science in Rome, Italy.

Achieving quantum supremacy does not necessarily mean that this type of computer will be useful for now, as it deals with esoteric calculations designed to be difficult for classic computers.

The capacity and computation of Jiuzhang has a potential for use in graphic theory, machine learning and quantum chemistry, according to the project’s research team.