Google announced today that it has demonstrated “quantum supremacy,” i.e. that they have solved a problem on a quantum computer that could not be solved on a classical computer. Google says
Our machine performed the target computation in 200 seconds, and from measurements in our experiment we determined that it would take the world’s fastest supercomputer 10,000 years to produce a similar output.
IBM disputes this claim. They don’t dispute that Google has computed something with a quantum computer that would take a lot of conventional computing power, only that it “would take the world’s fastest supercomputer 10,000 years” to solve. IBM says it would take 2.5 days.