Decades after his foundational experiments helped launch a new technological era, California physicist John Martinis has been recognized with the 2025 Nobel Prize in physics. Yet the 67-year-old researcher, a professor at the University of California, Santa Barbara, is not resting on his laurels. Instead, he remains deeply engaged in a personal and professional quest that has spanned 40 years: to transform the theoretical promise of quantum mechanics into a powerful, practical, and world-changing quantum computer.
Martinis, along with his doctoral advisor John Clarke of UC Berkeley and French physicist Michel Devoret of Yale, received the Nobel for work in the mid-1980s that demonstrated quantum phenomena on a macroscopic scale. Their experiments with superconducting electrical circuits known as Josephson junctions proved that effects like quantum tunneling and energy quantization were not confined to the subatomic realm. This breakthrough laid the essential groundwork for manipulating quantum states, the fundamental principle behind the qubits that power today’s quantum processors and Martinis’s continuing drive to build the fastest computers ever conceived.
Foundations of a Quantum Revolution
The work that earned the Nobel Prize dates back to Martinis’s doctoral studies at the University of California, Berkeley, in 1984 and 1985. Under the guidance of John Clarke and in collaboration with postdoctoral researcher Michel Devoret, Martinis conducted a series of pioneering experiments. Their research focused on a device called a Josephson junction, which consists of two superconducting components separated by a very thin insulating layer. In the strange world of quantum mechanics, particles can behave in ways that defy classical intuition, such as passing directly through a barrier in a phenomenon known as tunneling.
The team’s critical achievement was to design an electrical circuit that could exhibit these quantum behaviors on a scale large enough to be controlled and measured. By passing a current through their Josephson junction and analyzing the response to microwave pulses, they were the first to present a clear demonstration of quantized energy levels in the circuit. This meant the system could only absorb or emit energy in discrete, specific amounts, a hallmark of a quantum system. They also proved that quantum tunneling was possible with these larger, engineered objects, not just single particles. This work, lauded by the Royal Swedish Academy of Sciences for revealing “quantum physics in action,” provided the first tangible blueprint for building and controlling a qubit, the basic unit of quantum information.
From Theory to Google’s Lab
After establishing the fundamental principles, Martinis dedicated his career to advancing the technology. He joined the faculty at UC Santa Barbara in 2004, where he held the Worster Chair in Experimental Physics and continued to refine the physics of superconducting devices. His primary focus became the formidable engineering challenge of creating a viable quantum computer based on the Josephson junction qubits he had helped to pioneer. His lab became a world leader in generating high-fidelity qubits, which are essential building blocks for scalable and reliable quantum processors.
The potential of his team’s work attracted significant corporate interest. In 2014, Google established the Google Quantum AI Lab through a multimillion-dollar partnership with UC Santa Barbara, recruiting Martinis and his entire research group to lead the effort. The goal was ambitious and direct: to leverage Google’s vast resources and Martinis’s academic expertise to build the world’s first truly functional quantum computer. This move marked a significant moment in the field, signaling a shift from purely academic exploration to a focused, large-scale engineering project aimed at creating a machine with capabilities beyond any classical supercomputer.
Achieving ‘Quantum Supremacy’
The collaboration between Martinis’s team and Google culminated in a landmark achievement announced in a 2019 paper in the journal Nature. The team unveiled its “Sycamore” processor, a 53-qubit quantum machine that had successfully performed a calculation deemed practically impossible for even the most powerful conventional supercomputers. This was hailed as the first demonstration of “quantum supremacy,” a term for the moment a quantum computer solves a problem that would take a classical computer an intractable amount of time.
The specific task given to Sycamore was highly technical—checking the randomness of numbers produced by a random number generator. While a classical supercomputer would have taken an estimated 10,000 years to complete the calculation, Sycamore finished it in just over 3 minutes. The achievement was a powerful proof of concept, demonstrating that quantum processors built with superconducting qubits could reach a scale and reliability where they could outperform the world’s best existing technology. It provided tangible evidence that the foundational experiments from the 1980s had indeed unlocked a new frontier in computation, fueling a global race to develop larger and more powerful quantum systems.
A Career Beyond Corporate Labs
Despite the historic success with Sycamore, Martinis’s time at Google came to an end in April 2020. Following disagreements over the project’s direction and his reassignment to an advisory role, he resigned from the company. His departure highlighted the inherent tensions between the exploratory, academic pace of fundamental research and the product-driven goals of a major technology corporation. However, his work in the field was far from over. His expertise remained in high demand globally as nations and companies vied for leadership in the quantum technology space.
Later in 2020, Martinis embarked on a new chapter, moving to Australia to join Silicon Quantum Computing. This startup, founded by Professor Michelle Simmons, is pursuing a different approach to building qubits, using precisely placed atoms in silicon. This move demonstrated Martinis’s persistent dedication to solving the core challenges of quantum computing, regardless of the specific platform or institutional setting. It underscored his identity as a hands-on physicist driven by the fundamental science and engineering problems that must be solved to make quantum computation a reality.
The Unfinished Quest for a Practical Machine
Now in his late 60s, Martinis remains motivated by what he calls his “professional dream”: to see the development of a truly useful quantum computer that can be applied to solve real-world problems. He has stated that while he is old enough to retire, he has no intention of doing so while this goal remains on the horizon. His focus has shifted from demonstrating supremacy to achieving practicality, moving the technology out of the lab and into the hands of scientists, engineers, and researchers who can use its unique power.
The potential applications of such a machine are vast and transformative. The Nobel committee noted that the foundational work by Martinis and his colleagues has paved the way for the next generation of quantum technologies. These include developing new pharmaceuticals, discovering novel materials with exotic properties, breaking complex cryptographic codes, and creating ultra-secure communication networks through quantum cryptography. Quantum sensors, another application, could offer unprecedented precision in measurement. Martinis’s ongoing work is aimed at overcoming the remaining hurdles, such as improving qubit stability and reducing errors, which are necessary steps to unlock this potential and complete the four-decade journey from a Nobel-winning experiment to a revolutionary new tool for science and technology.
