Google claims it has achieved 'quantum supremacy' – but IBM disagrees

Task that would take most powerful supercomputer 10,000 years 'completed by quantum machine in minutes'

For Google, it was a historic announcement: a declaration that it had won the race to achieve "quantum supremacy" - the moment that a sophisticated quantum computer performed a task that stumped even the most powerful standard computer in the world.

But for all the fanfare, which saw Google's CEO, Sundar Pichai, compare the feat to building the first rocket to reach space, the claim has sparked a bunfight. The tech firm's rival, IBM, was swift to dismiss the excitement. Google has not, it asserts, achieved the highly prized goal of quantum supremacy.