On 23 October, researchers from Google have announced that the company’s quantum chip Sycamore had reached “quantum supremacy”, which means that it had successfully cracked a problem that regular machines simply aren’t equipped to deal with, unless given a deadline that’s far too long for practical purposes.
To test what Sycamore is capable of, researchers performed a series of randomised operations on its 53 quantum bits (or qubits) and then measured their individual values. After repeating the process a number of times, the distribution of numbers was found to be close, yet not exactly, random, which the team claims is due to quantum effects.
For comparison, calculating the same distribution would take today’s most advanced supercomputer in the world around 10,000 years, whereas the same operation takes Sycamore no longer than 200 seconds, or a bit over 3 minutes.
“With the first quantum computation that cannot reasonably be emulated on a classical computer, we have opened up a new realm of computing to be explored,” wrote Google researchers John Martinis and Sergio Boixo on Google’s AI blog.
To be fair, the task employed in the experiment was specifically designed to favour quantum computers and, furthermore, is decidedly not a practical one. In addition, other researchers have challenged the paper – currently out in the journal Nature, but published by mistake on a NASA website in September – claiming that Google has not achieved what it claims to have achieved.
Furthermore, not everyone agrees that “quantum supremacy” – a concept introduced by theoretical physicist John Preskill in 2012 – is all that useful and may lead to hype more so than to real-world applications.
Regardless of these reservations, however, the achievement is no doubt quite remarkable. In the words of computer scientist Bill Fefferman from Chicago University, who was not involved in the research:
“I think the jury is still out as to whether this is really quantum supremacy, [but] no matter what happens, I’m convinced it’s an impressive experiment. They’re paving new ground, and they’re going where no one has gone before.”