Scientists ‘have achieved quantum supremacy’, in discovery that could change the world

‘We are only one creative algorithm away from valuable near-term applications’

Scientists claim to have achieved “quantum supremacy”, a breakthrough that could change the course of computing history.

Google researchers say they have broken through the milestone, meaning that a quantum computer has undertaken an operation that classical computers cannot.

Quantum supremacy marks the first step in a field that researchers claim could go on to change the world. Quantum computers are theoretically capable of doing work much quicker than the computers we use today.

IBM researchers have already criticised Google’s claims of a breakthrough, suggesting that the new discovery is not as profound as promised. But the new research has finally been published in the journal Nature, and lays out the workings of the long-rumoured breakthrough.

The Google researchers state in the paper that their computer, known as Sycamore, is able to conduct a task in 200 seconds that would take around 10,000 years on a traditional system.

“This dramatic increase in speed compared to all known classical algorithms is an experimental realisation of quantum supremacy for this specific computational task, heralding a much-anticipated computing paradigm,” the researchers write in the paper.

The task used by Google researchers to test their system is largely useless for now, and its main function is to generate random numbers. But it is the first time that any task of this kind has ever been successfully demonstrated, and could very soon lead to more practical applications, the researchers claim.

“As a result of these developments, quantum computing is transitioning from a research topic to a technology that unlocks new computational capabilities,” the researchers conclude. “We are only one creative algorithm away from valuable near-term applications.”

The company now hopes to build a system that can conduct more broad operations, which could be used across a variety of different fields.

“Such a device promises a number of valuable applications,” the researchers wrote in a blog post. “For example, we can envision quantum computing helping to design new materials – lightweight batteries for cars and airplanes, new catalysts that can produce fertilizer more efficiently (a process that today produces over 2 per cent of the world’s carbon emissions), and more effective medicines.

“Achieving the necessary computational capabilities will still require years of hard engineering and scientific work. But we see a path clearly now, and we’re eager to move ahead.”

Google’s breakthrough had been rumoured since an early version of the paper was leaked online last month.

It had already been criticised by IBM, who argued that the paper was fundamentally flawed because Google had drastically overestimated the difficulty of the task and how long it would take on a classical computer. The task would actually take about 2.5 days on a classical computer and would be completed more effectively than it was with Google’s quantum computer, the firm argued in a blog post published two days before the Nature paper was made available, though it is yet to demonstrate the claim.

The phrase “quantum supremacy” has also attracted criticism, both for its similarity to white supremacy and the fact it could encourage hyped-up reporting on the status of quantum technology. Both of those arguments were addressed by John Preskill, the scientist who coined the phrase in 2012, in a recent article where he concluded that Google’s breakthrough is nonetheless very significant.