Content area
Full Text
The company says that its quantum computer is the first to perform a calculation that would be practically impossible for a classical machine.
Scientists at Google say that they have achieved quantum supremacy, a longawaited milestone in quantum computing. The announcement, published in Nature on 23 October, follows a leak of an early version of the paper five weeks ago, which Google did not comment on at the time.
In a world first, a team led by John Martinis, an experimental physicist at the University of California, Santa Barbara, and Google in Mountain View, California, says that its quantum computer carried out a specific calculation that is beyond the practical capabilities of regular, 'classical' machines (F. Arute et al. Nature 574, 505-510; 2019). The same calculation would take even the best classical supercomputer 10,000 years to complete, Google estimates.
Quantum supremacy has long been seen as a milestone because it proves that quantum computers can outperform classical computers, says Martinis. Although the advantage has now been proved only for a very specific case, it shows physicists that quantum mechanics works as expected when harnessed in a complex problem.
"It looks like Google has given us the first experimental evidence that quantum speed-up is achievable in a real-world system," says Michelle Simmons, a quantum physicist at the University of New South Wales in Sydney, Australia.
The feat was first reported in September by the Financial Times and other outlets, after an early version of the paper was leaked on the website of NASA, which collaborates with Google on quantum computing, before being quickly taken down. At that time, the company did not confirm that it had written the paper, nor would it comment on the stories.
Although the calculation Google chose - checking the outputs from a quantum random-number generator - has limited practical applications, "the scientific achievement is...