Google trumpeted its quantum computer that outperformed a conventional supercomputer. A Chinese group says it's done the same, with different technology.
Last year Google won international acclaim when its prototype quantum computer completed a calculation in minutes that its researchers estimated would have taken a supercomputer 10,000 years. That met the definition for quantum supremacy—the moment a quantum machine does something impractical for a conventional computer.
Thursday, China’s leading quantum research group made its own declaration of quantum supremacy, in the journal Science. A system called Jiuzhang produced results in minutes calculated to take more than 2 billion years of effort by the world’s third-most-powerful supercomputer.
The two systems work differently. Google builds quantum circuits using supercold, superconducting metal, while the team at University of Science and Technology of China, in Hefei, recorded its result by manipulating photons, particles of light.