Abhishek Sinha
The 2025 Nobel Prize in Physics has been conferred upon John Clarke, Michel Devoret, and John Martinis for their groundbreaking discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit. The announcement was made on Tuesday, October 7.
In his initial reaction, laureate John Clarke expressed astonishment upon learning of the honour.
“I’m completely stunned. It never occurred to me that our work would form the basis of a Nobel Prize,” he said.
During a press conference following the announcement, Clarke reflected on the research that earned him and his collaborators the prize, remarking:
“Our discovery is, in many ways, the foundation of quantum computing.”
Why They Won the 2025 Nobel Prize in Physics
This year’s Physics Nobel celebrates experiments that proved quantum tunnelling can be demonstrated on a macroscopic scale, involving vast numbers of particles — not just single atoms or electrons.
Clarke, Devoret, and Martinis designed a series of superconducting circuit experiments that successfully revealed how the strange properties of the quantum world could be observed in an object large enough to hold in one’s hand.
The experiment’s chip — roughly a centimetre across — contained a superconducting electrical circuit. Unlike earlier studies limited to systems with a few particles, their work showcased tunnelling and energy quantisation in a system containing billions of Cooper pairs, filling the entire superconductor.
Their research effectively bridged the gap between microscopic quantum effects and macroscopic physical systems, a milestone that has laid crucial groundwork for the evolution of quantum computing.
Understanding Quantum Mechanics and Tunnelling
Quantum tunnelling is a process where particles can pass through a barrier that, according to classical physics, should be impenetrable. In the quantum realm, chance and probability determine when and how this occurs.
For instance, certain atomic nuclei have barriers so high and wide that it may take a long time for a particle to appear outside, while others decay more readily. This randomness is intrinsic to quantum mechanics, which governs behaviour at the microscopic level — the scale of atoms and subatomic particles.
By contrast, macroscopic objects (like a ball) contain an enormous number of particles and follow the predictable laws of classical physics. When you throw a ball at a wall, it always bounces back — but a single quantum particle might, against all expectation, pass straight through the wall.
This counterintuitive effect — tunnelling — is one of the most fascinating and vital principles in quantum mechanics and has far-reaching applications in modern technologies, including quantum computers, semiconductors, and superconductors.
Background and Significance
The 2025 laureates’ achievement marks a turning point in the quest to harness quantum phenomena in practical, scalable systems. Their experiments demonstrated that quantum behaviour isn’t confined to the invisible atomic world, but can manifest in everyday materials engineered with precision.
In doing so, Clarke, Devoret, and Martinis have not only advanced our understanding of quantum physics, but also accelerated the technological revolution driving the next generation of computing and materials science.
