John Martinis and Per Delsing
Chalmers' rigorous work with the basic building blocks of the quantum computer is the right way to go, according to John Martinis, here with Per Delsing in Chalmers' quantum computing lab.​​

Quantum computer project boosted by superstar

John Martinis, superstar in quantum computing and former leader of Google's venture in the field, has spent the last month at Chalmers as a guest researcher.
“The quantum computing team at Chalmers is doing all the right things and is in a position to make good progress,” he says.
In 2019, a research team at Google made a big breakthrough: their quantum computer managed to surpass the world's best supercomputers in solving a computational task (read more in Big breakthrough for quantum computers​).

The chief scientist behind Google's quantum computer, world-famous Professor John Martinis, left Google the following year and returned to his university, University of California, Santa Barbara. However, he spent last month in Gothenburg as a guest researcher in Chalmers’ quantum computing team where Per Delsing and Jonas Bylander lead the engineering of a Swedish quantum computer. The focus has mainly been on the basic building blocks of the quantum computer – the qubits.

Broke new ground

Although Martinis and his former colleagues at Google broke new ground with their 53-qubit quantum computer, he admits that it did not work quite as well as they wanted. But it was difficult to find out why in the complex system that made up the quantum computer.

John Martinis“Today people tend to focus on how many qubits you have. In my opinion, one needs to go back and improve the qubits before scaling up. I’ve been thinking quite deeply on how to make superconducting qubits better, and I wanted to come here because the Chalmers team is doing great work on this,” says John Martinis.

He does not have his own research group at the moment, but still many ideas about experiments that could be done to better understand the factors that affect the performance of the qubits.

“Many of the experiments I wanted to do last year, they already did here. From their data I’ve been able to better understand what’s going on with the materials in the qubits. And I have shared my ideas on how to analyze the data and about further experiments to do.”

"Many valuable suggestions"

Per Delsing describes John Martinis' visit as a shot in the arm:
“The entire group looks up to him, like a hero. The fact that we all got to spend time with him and his deep interest in what everyone is doing has been like a huge shot. John is extremely skilled and experienced and has given us many valuable suggestions on how to continue our work.”
The plan now is to stay in touch, to share results, thoughts and ideas.
“I think that really good things will come out of this,” says John Martinis.

Text: Ingela Roos
Photo: Kamanasish Debnath

More about Chalmer’s quantum computer project

The research is part of the Wallenberg Centre for Quantum Technology (WACQT), a twelve-year, billion-SEK investment with two main purposes: to develop Swedish expertise in quantum technology, and to build a useful quantum computer with at least one hundred quantum bits. The research centre is mainly funded by the Knut and Alice Wallenberg Foundation.

Read more:

Engineering of a Swedish quantum computer set to start (initial press release from 2017)
Discover quantum technology (introduction to quantum technology)
Quantum computing (introduction to quantum computing)
Wallenberg Centre for Quantum Technology (WACQT)
Research in quantum computing and simulation (about quantum computing research within WACQT) ​

Page manager Published: Thu 07 Oct 2021.