Google Lays Claim to Quantum Supremacy

October 28, 2019 - 7 minutes read

Quantum supremacy has arrived! Researchers at Google have revealed that they’ve built a quantum computer that has beaten the world’s most powerful supercomputers at one type of calculation.

The achievement comes much sooner than most industry insiders anticipated, and many of them are questioning the validity of Google’s claim. But if true, the tech titan’s recent accomplishment could lead to monumental advancements for the development of artificial intelligence (AI) and other emerging technologies.

1 Small Step for Google, 1 Quantum Leap for Mankind?

The main goal of quantum computing is to exponentially enhance a computer’s processing power and speed so it can simulate large systems more effectively.

Whereas classical computers store information with binary code (0s and 1s), quantum computers employ qubits (quantum bits), which can be both 0 and 1 at the same time. This concept can certainly be confusing (we are dealing with quantum mechanics, after all), but the important thing to remember here is that this allows the amount of information that can be encoded to dramatically increase.

Quantum supremacy refers to the idea that a quantum computer drastically outperforms a traditional computer to the point that the latter is obsolete in this context. Achieving this milestone would be a big step towards useful and practical quantum computers. And according to Google’s recent announcement, that’s exactly what the San Francisco Bay Area developer has done with a chip consisting of only 53 qubits.

“This achievement is the result of years of research and the dedication of many people,” said Hartmut Neven, Engineering Director at Google. “It’s also the beginning of a new journey: figuring out how to put this technology to work. We’re working with the research community and have open-sourced tools to enable others to work alongside us to identify new applications.”

Not only would quantum computing be a game-changer for AI and machine learning applications, but it would also drive immense advancements in traditional scientific fields like physics and chemistry. But don’t expect to start seeing quantum computers everywhere right away.

10,000 Years vs. 200 Seconds

While impressive, Google’s recent quantum computing feat was not exactly useful for anything but proving quantum supremacy; the experiment was intentionally designed to be difficult for a classical computer. Google’s quantum computer, known as Sycamore, performed a task known as random circuit sampling. Basically, the company’s team of researchers executed a sequence of randomized operations on the qubits. Then they measured the qubits’ values.

After repeating this exercise numerous times, the resulting distribution of numbers was extremely close to random — and would be extremely hard for a classical computer to calculate. To put this difficult into perspective, a state-of-the-art supercomputer would take approximately 10,000 years to complete the task. Sycamore did it in 200 seconds.

“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,” reported Google researchers Sergio Boixo and John Martinis in a recent Google AI blog post.

This quote is actually a bit of an understatement. Quantum supremacy challenges a principle of computer science known as the extended Church-Turing thesis, which claims that all reasonable types of computation can be completed by classical computers. If Google’s claim to quantum supremacy is true, it would be the first legitimate violation of this principle.

But many quantum computing competitors have their doubts.

A Concept Mired in Controversy

From its inception in 2012 by theoretical physicist John Preskill, quantum computing has always attracted its fair share of controversy. Not only does the term itself sound like news headline hype, but it doesn’t concretely focus on any metrics implying practical usefulness — factors which quantum physicists prefer to use for ease of measurement.

So it should come as no surprise that Google’s quantum supremacy claim has garnered some skepticism. Even before Google officially released details of its feat, IBM researchers were already challenging it through a paper posted on research repository They suggested that Google’s estimate of 10,000 years for a classical computer to accomplish random circuit sampling was way off; with an improved technique, a supercomputer could do it in 2.5 days.

It’s worth noting that IBM is one of Google’s prime competitors in quantum computing and has also developed a 53-qubit quantum computer. But, like many other quantum researchers, IBM favors different metrics, such as quantum volume, over quantum supremacy.

Because IBM has not yet verified their 2.5-day computation calculation, the state of quantum supremacy is debatable. Though, regardless of supremacy, Martinis points out that, “In the end, this experiment is about building the most powerful quantum computer in the world right now and showing that … things are working well.”

Quantum supremacy may still be up for debate, but Google’s achievement is certainly a step in the right direction. With complete control of quantum computers, researchers could tackle some of the most vexing problems in the world. They could crack rock-solid encryption techniques used to secure modern online communications, they could more closely examine chemical reactions of new medicines, they could… well, you get the idea.

The title of quantum supremacy isn’t as important as what this progress represents. “I think the jury is still out as to whether this is really quantum supremacy,” says Bill Fefferman, a computer scientist at the University of Chicago. “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.”

In due time, this trailblazing will usher in a new era of computing which will, in turn, profoundly change the world. Big things start small. And right now, it appears that a better future awaits us in 53 qubits.

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