Nobel Prize winner John Martinis on making quantum physics visible

Nobel Prize winner John Martinis speaks with the calm precision of someone who has spent his life studying uncertainty. When he describes quantum mechanics, his tone is not mystical but methodical, as if he were explaining how to adjust the focus on a microscope.

“You can see quantum mechanics in electrical circuits,” he told IBM Think in an interview. “You could see it as noise at first, and it was not understood.”

That simple statement captures the work that recently earned Martinis the 2025 Nobel Prize in Physics. He shares the award with John Clarke, his former adviser at the University of California, Berkeley, and Michel Devoret of Yale University. The three scientists were recognized for experiments that, as the Nobel Committee put it, revealed “quantum physics in action.” Their collaborative work, which began in the 1980s and continued through the following decade, demonstrated that even an electrical circuit, something large enough to be visible, could behave according to the laws that generally apply only to atoms.

Their work demonstrated that electrons could flow through thin insulating barriers and occupy discrete energy levels, like the orbitals of atoms. These circuits influenced the development of superconducting qubits, the heart of today’s quantum computers.

A qubit, short for quantum bit, is the smallest unit of information in a quantum computer. Unlike an ordinary bit, which can be only zero or one, a qubit can exist in a superposition of both states at once. That makes quantum computers useful because they can process many possibilities simultaneously, solving specific problems much faster than regular computers.

“A quantum computer manipulates this wider class of logical elements,” Martinis said. “Instead of zero and one, it can be zero plus one, or any combination between.”

Martinis’ journey to the Nobel Prize began at UC Berkeley, where he was a graduate student in the early 1980s. He joined a team led by John Clarke, a pioneering physicist who had helped invent the SQUID in the 1970s, a device so sensitive it can pick up magnetic fields far weaker than the Earth’s.

When asked if he imagined that his early experiments would one day lead to quantum computers, he didn’t hesitate. “When we started, not at all,” he said.

The noise fascinated Martinis. It hinted that something larger was happening inside the circuits, something that might connect the everyday world of electricity to the strange mathematics of quantum mechanics. Together with Clarke and Devoret, he began constructing superconducting devices known as Josephson junctions, made of two metal layers separated by a thin insulator.

When the device was cooled to near absolute zero, electrons could pass through the insulating barrier, a phenomenon known as quantum tunneling.

“You have a wire with billions of electrons in it, and it’s the currents and voltages that obey quantum mechanics,” Martinis said.

The experiments were extraordinarily delicate. Every vibration, fluctuation in temperature or magnetic field could destroy the effect they were trying to measure.

“We spent a few years figuring this out and demonstrating this conclusively,” he said of his experiments in the 1980s. It wasn’t until later that he and his colleagues realized their work had opened a new path toward controlling quantum behavior in electrical circuits. “At the time, it was just a basic science question,” he said.

By the end of his doctoral work in the mid-1980s, Martinis had begun to see how his results could point to something larger. Around that time, at a conference in Santa Barbara, he attended a lecture by Richard Feynman, the theoretical physicist who was among the first to propose the idea of a quantum computer.

The talk gave him a sense of direction. “Once you can do quantum mechanics in electrical circuits,” Martinis said, “that’s a very natural way to build a quantum computer, because you just build it like a regular integrated circuit and you use all the technology.”

By the early 2010s, superconducting circuits had emerged as one of the most promising paths to quantum computing. In 2014, Martinis joined Google to lead its quantum hardware team. He now leads his own startup.

Martinis said he is aware of how much remains to be done. Martinis noted that quantum computers are still prone to errors, even from the most minor interference. Making them reliable will require developing new techniques to detect and correct those errors while maintaining system stability.

“You can have 10 things that are wonderful,” he said, “but if one thing is not right, nothing works.”

Despite the Nobel and the decades of breakthroughs, Martinis still talks like a craftsman checking a circuit for loose connections. “Like many other people in the world, I want to build a useful quantum computer,” he said. “I’ve gone from showing some of the foundations of it to working with people and showing that it’s powerful. But next, I want to build something useful.”

Outside the lab, he finds calm in familiar routines. “Electronics is a big hobby of mine,” he said. “It’s therapy from all the stress in the world.” He keeps a small workbench at home, filled with circuit boards and tools, and often spends hours soldering and testing. “It grounds me,” he said. “It reminds me how hard it is to build something and get it to work.”

On Sundays, he and his wife take ballroom lessons, and he cannot resist connecting the art form back to the study of motion. “When we’re doing the dance moves, I explain it in terms of physics, angular momentum, the mechanics of it,” he said. “The most important thing you learn dancing is that your partner loves to get twirled. You just have to learn how to do it properly.”

That image is a fitting metaphor for Martinis’s life in science: the elegance of motion hidden beneath structure, precision that allows freedom. The circuits he first built in Berkeley made the invisible world of quantum mechanics visible for the first time. Decades later, the same quiet curiosity still moves him.

“It’s exciting to see quantum mechanics in action,” he said. “That’s what’s always kept me going.”