Paul van Gerven
23 September 2019

Google apparently has built a quantum computer that can defeat the world’s best supercomputers in a specific task. The machine reportedly performs a series of operations in 200 seconds that would take a supercomputer 10,000 years to complete. Once confirmed, this would be the first time so-called quantum supremacy has been achieved.

The news was first brought by the Financial Times, citing a scientific paper on NASA’s website. The publication has since been removed, but someone anonymously posted an apparent draft on Pastebin.

Credit: Google/Erik Lukero

According to the paper, Google had a quantum computer based on superconducting circuits perform random operations on the 53 qubits available. Sampling the output produces a set of bit strings that, due to quantum interference, resembles a speckled intensity pattern of a scattered laser. “Classically, computing this probability distribution becomes exponentially more difficult as the number of qubits (width) and number of gate cycles (depth) grow,” the paper states.

The calculation is basically a simple quantum simulation, which is indeed very time-consuming to do classically. The result, however, is not useful in any way.