John Martinis is leading a Google research team in the pursuit of quantum supremacy, where a quantum computer solves within one second a calculation that would take a supercomputer days or weeks to complete.

John Martinis is leading a Google research team in the pursuit of quantum supremacy, where a quantum computer solves within one second a calculation that would take a supercomputer days or weeks to complete. Photo: Google

A research scientist at Alphabet Inc.’s Google is working to solve two of the most pressing challenges of quantum computing, a field that is making rapid advances and could soon begin solving problems that are currently out of reach.

John Martinis, a physics professor at University of California, Santa Barbara, joined Google in 2014 to help build a quantum computer that eventually might be able to sort through a vast number of variables - more than the number of atoms in the universe - to come up with a probable solution within a fraction of a second.

“The real excitement is, if you can do it efficiently, you can start solving problems that you couldn’t even dream of solving on a classical computer,” said Dr. Martinis, speaking Thursday to CIO Journal from Russia, where he spoke Friday at the International Conference on Quantum Technologies in Moscow.

He was expected to speak to a crowd of about 2,500 people from around the globe including researchers, company executives and Russian government officials about the technology, Google’s role in it, and its business applications. The weeklong conference, organized by the Russian Quantum Center, is the fourth of its kind since 2011 and brings together many of the world’s foremost experts in quantum mechanics.

This year, the conference is being held at a major turning point for the quantum computing field. Technology executives in sectors ranging from biotechnology to automotive and materials manufacturing have announced partnerships this year with technology vendors on quantum computing experiments, and China and other countries have made technological leaps in quantum computing.

Traditional computers use binary digits, or bits, which can either be 0s or 1s. Quantum computers use quantum binary digits, or qubits, which represent and store information in both 0s and 1s simultaneously. This means the computers have the potential to sort through a vast number of possibilities within a fraction of a second to come up with a probable solution.

Google is among several technology giants including Microsoft Corp. and International Business Machines Corp. working on building general-purpose, scalable quantum computing machines. IBM has developed a cloud-based quantum computing service that is available for commercial business use. Microsoft is working on building a quantum computer that’s fault-tolerant and scalable using a technology called topological quantum computing.

In order to commercialize quantum computing, Dr. Martinis said there are two essential problems that his 20-person Santa Barbara-based research team is trying to solve. One is the fact that qubits can’t yet maintain their quantum mechanical state for more than a fraction of a second, in part because they are delicate, easily disrupted by changes in temperature, noise or frequency. This is referred to by physicists as decoherence.

Another major challenge is that current quantum computing systems don’t have fault tolerance like traditional computers, meaning the delicate qubits won’t continue operating in the event of a disruption.

The Google team is working on solving those problems, first on a 22-qubit chip the company created last month that’s currently sitting in a dilution refrigerator and undergoing tests. The dilution refrigerator helps cool the device to temperatures that are colder than outer-space, which makes it possible to achieve quantum mechanical effects, including entanglement, when qubits share the same properties regardless of the distance between them.

The 22-qubit chip is a small device in comparison to the 300-qubit chip that Google one day expects could sort through a number of variables larger than the number of atoms in the universe. But the team wants to start relatively small and then ramp up.

“We want to make sure we understand a 22-qubit device really well,”he said. “There’s no sense in going on to more qubits unless the coherence is (controlled).”

By the end of this year, the team aims to create a 45-qubit to 50-qubit chip, which could achieve what Dr. Martinis calls “quantum supremacy,” meaning it could perform a calculation within one second that would take a supercomputer days or weeks to complete.

“Quantum supremacy is kind of step one in the plans that we have,” he said. “In the next two, three or four years, we plan to go way beyond that.”

In the future, Dr. Martinis envisions a world in which quantum computers and supercomputers will be used in concert with each other. The most applicable uses for quantum computing would be in chemistry and machine learning, he said.

Companies such as Biogen Inc., Volkswagen AG and The Dow Chemical Co. have already begun experimenting with quantum computing in those two areas, through quantum computing technology providers including D-Wave Systems Inc.

Biogen, for example, is exploring how quantum computers could speed up drug discovery. Volkswagen is researching how quantum computing and machine learning could be used to optimize traffic flow in densely populated cities.