TQD Exclusive Interview: Quantum Pioneer John Martinis Still Wants to Build Quantum Computers — and Make Them More Powerful

John Martinis, professor of physics at the University of California, Santa Barbara, may have moved on from Google’s quantum computer project, but he hasn’t moved on from quantum computing. In an exclusive interview with The Quantum Daily, Martinis said he still is involved in the quantum computing community and wants to pass on the knowledge he’s gained from decades in the field, as well as from years spent helping lead Google’s team in developing the quantum computer recognized as the first to achieve quantum supremacy.

“This has been a good time to figure out what I want to do next,” said Martinis. “Before my goal was to build a useful quantum computer for Google. Now, I just want to build a useful quantum computer for someone. I would love to head a team — and if that’s not in the cards — then I want to help someone build it.”

The quantum computing pioneer added that he is still excited about the future of quantum and is looking forward to continue to contribute to that future. “There are probably some things that I know, or have thought about deeply, that may help,” said Martinis. “I’m excited that there’s a lot of science and engineering sill left to do.”

“What I think I figured out in the last year — with some ideas from other people at Google — is how to scale up the qubits. Right now the qubit number is around 50 and we definitely know how to scale up to thousands of qubits, but I have an idea on how to scale up to millions of qubits, which is what you ultimately want to do.”

Scaling Up to Millions of Qubits

Martinis, who is widely recognized as one of the experts on quantum computers based on superconducting qubits, is particularly interested in finding ways to increase the number of superconducting qubits in a quantum computer. Because much of the computational power of a quantum computer is diminished due to environmental noise, adding more qubits is necessary to develop quantum computers that can be used for practical purposes.

“What I think I figured out in the last year — with some ideas from other people at Google — is how to scale up the qubits,” said Martinis. “Right now the qubit number is around 50 and we definitely know how to scale up to thousands of qubits, but I have an idea on how to scale up to millions of qubits, which is what you ultimately want to do.”

Building a quantum computer and finding ways to expand the number of qubits are just a few of the business ventures and educational projects that the physicist said he is considering. Martinis also said that his experience in developing Google’s quantum computer has also given him an appreciation and an understanding of systems engineering in superconducting qubits. In creating something as complex as a quantum computer, engineering isn’t enough, the engineering teams from all different aspects of the device must be able to work together, he said.

“Systems engineering for superconducting qubits is something I haven’t talked about much. I would like to give a lecture series on everything I learned about this to help people with some of those challenges,” he said.

“I think superconductivity has great advantages, although there is still some physics to figure out so it works better. But, it’s good that there’s a broad spectrum of ideas out there.”

Many Qubit Types

Whether it’s superconducting qubits, or trapped ions, or annealing, quantum experts are exploring multiple paths to developing quantum computers that can be used for practical applications. As these technologies mature and explore, camps are arising within the industry, essentially forming around what particular qubit type horse these teams have in the race. For Martinis, having all of these approaches to quantum computing isn’t a weakness of the field, it’s a strength. He plans to spend more time learning about these other approaches to quantum computing in depth.

“I want to learn about the other approaches and learn what the critical issues are with each approach and try to understand more globally what needs to be done to build a quantum computer — and see if I can help,” said Martinis. “It’s funny — everyone, if you would interview them, would say ‘my qubit type is the best’ and everyone is optimistic about their qubit as a way to push forward. Clearly some are going to be better than others. I think superconductivity has great advantages, although there is still some physics to figure out so it works better. But, it’s good that there’s a broad spectrum of ideas out there.”

“As we start solving those problems, humans are pretty creative, so it’s extremely likely that we’ll find more and more applications as was done with regular computers.”

Taking the Quantum Longview

While many involved in the quantum computing industry see the incredible complexity of designing and building a quantum computer as one of the field’s most significant challenges, Martinis said that the push toward scientific discovery is what excites him the most about working in the field.

In much the same way that John F. Kennedy declared that the difficulty of the moon mission was part of the reason to try to achieve the goal, Martinis believes that, beyond the business and commercial possibilities, the complexity of the quantum computing challenge and the scientific discovery that it could open up makes it a worthy goal.

“What’s interesting about quantum computing is that it’s a totally new computing paradigm and we may be able to solve problems that were impossible before,” said Martinis.

He added that he feels confident that those real-world applications for quantum computers are coming.

“As we start solving those problems, humans are pretty creative, so it’s extremely likely that we’ll find more and more applications as was done with regular computers,” said Martinis.

As a physicist and an experimentalist, quantum computers represent a profound scientific challenge, according to Martinis.

“There’s a reason to do it, it’s interesting to do, it’s a big technical challenge — It’s a grand scientific quest,” he said. Grand scientific challenges are unlikely to be wrapped up in a few years, so Martinis offers some expectations setting about building quantum computers and developing the quantum computing field.

“There are other scientific quests, for astronomers to understand the universe, which is a long quest that takes a long time just to build the tools to do that — and I think the same thing goes for quantum computers,” said Martinis. “It’s taken a long time to figure out the science and technology.”

While quantum computers seem revolutionary today, the devices are built on a lot of small scientific revolutions, according to Martinis, whose own career demonstrates that science, especially quantum science, requires commitment and patience to move from one scientific challenge to the next. As a graduate student, Martinis became interested in quantum technologies while working toward his doctorate in physics at the University of California, Berkeley.

“As a graduate student in the early 1980s I went to some conferences and I was working on superconducting devices, but in John Clarke’s group at Berkeley, they were looking at the global quantum mechanical effects of quantum noise,” he said. “And it was fascinating to see quantum mechanical effects on an electrical device. Of course, quantum mechanics describes superconductivity and the ways it works, but there’s another level of quantum mechanics that describes the electrical behavior of all the electrons moving around in the device. That interested me right away: that you could build electronic devices where you could see really interesting quantum behavior.”

He added that listening to Nobel prize winners, such as Anthony Leggett and Richard Feynman, also influenced his research direction.

Martinis recognizes that it is still early — very early — in the development of quantum computing, but he is cautiously optimistic about its future, emphasizing that part of what makes the field so fascinating is that it calls on scientists to intelligently and rigorously test the limits of quantum mechanics.

“I’ve been working in this field for many years now and I feel I know what’s possible and I’m excited about the future,” said Martinis. “And especially building and testing quantum computers.”