A team led by researchers from Google, NASA, and Oak Ridge National Laboratory has officially claimed to have reached the technological milestone of quantum supremacy.
For the first time, a quantum computing system has solved a problem that cannot be done by a standard supercomputer – at least within a reasonable time, since according to Google it would have taken 10,000 years. This milestone, known as quantum supremacy, is a big step toward useful quantum computers; that is, machines capable of performing tasks that are beyond the reach of conventional computers.
The researchers performed the task with a chip consisting of just 53 qubits , the quantum version of bits that we can find in everyday computers.
Are we going to have quantum computers soon?
The calculation that Google’s quantum computing system performed was not particularly helpful, as the task in question was one designed to play to the strengths of quantum computers and can be difficult for a non-quantum or “traditional” computer.
As if this were not enough, some researchers are rejecting Google’s claim to have achieved quantum supremacy, arguing that the milestone has not yet been achieved.
“This experiment establishes that current quantum computers can outperform the best conventional computing for a synthetic benchmark,” says Travis Humble, director of the Oak Ridge Institute for Quantum Computing. “There have been other efforts to try this, but our team is the first to demonstrate this result in a real system.”
The moment was drawing near
Not only because the concept of quantum supremacy has been widely contemplated for decades (although the specific term dates from 2012), but because a few weeks ago there was a leak of the Google document, giving the world a sneak peek at the groundbreaking claims it now collects. the journal Nature .
The concept of quantum supremacy, proposed in 2012 by theoretical physicist John Preskill, has sparked controversy. The term lends itself to exaggeration, and some quantum physicists prefer to focus on metrics that imply practical utility, rather than supremacy.
But according to Caltech’s Preskill, the demonstration of quantum supremacy is not only a milestone in computing, but also a breakthrough in scientists’ understanding of quantum mechanics. Making a machine that can perform complex quantum calculations on the scale of quantum supremacy is “an exploration of physics that we have never been able to do before,” says the expert.
How did they do it?
Using the Sycamore quantum processor, the Google researchers performed a task called random circuit sampling , where it had to verify a set of numbers with a truly random distribution.
Sycamore managed to complete the task in 3 minutes and 20 seconds. According to Google experts, Summit, the best supercomputer in the world, would take 10,000 years to complete the same task.
“The classical simulation time, currently estimated at 10,000 years, is likely to be reduced by improved classical hardware and algorithms, but given that we are currently 1.5 trillion times faster , we are comfortable claiming this achievement,” he says. Brooks Foxen of UC Santa Barbara and co-author of the work.
“Ultimately this experiment is about building the most powerful quantum computer in the world right now and showing that things are working well,” says John Martinis, one of the leaders of the research.
Once physicists master control of quantum computers, the machines could be scaled up to help with useful problems, such as studying the physics behind chemical reactions or even cracking encryption techniques used to secure Internet communications. But those achievements are still far in the future, according to experts. Quantum supremacy is a step in that direction.
In a comment on Google’s article to announce this technological milestone, MIT researcher William Oliver compared Google’s achievement to the first flights of the Wright brothers.
Referencia: Quantum supremacy using a programmable superconducting processor. Frank Arute, Kunal Arya,John M. Martinis… Nature 574, 505–510 (2019) Published 23 October 2019 DOI: https://doi.org/10.1038/s41586-019-1666-5
