Quantum Tunneling, a phenomenon in which particles pass through a barrier that they shouldn’t have enough energy to overcome, according to classical physics. In October 2025, the Royal Swedish Academy of Sciences awarded the Nobel Prize in Physics to John Clarke, Michel H. Devoret, and John M. Martinis “for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit.”
Their work demonstrated that quantum effects—traditionally confined to the microscopic world of atoms and electrons—can manifest in systems large enough to be handled and engineered.
From Microscopic to Macroscopic: Quantum Tunneling and Quantisation in a Chip
At the heart of their experiments was a superconducting electrical circuit, cooled to extreme low temperatures, employing a Josephson junction—a thin insulating barrier between two superconductors.
In classical physics, once a system is “trapped” in a state, it cannot hop over an energy barrier unless enough energy is supplied. But in quantum mechanics, tunnelling allows the system to traverse the barrier without the classical energy requirement. Clarke, Devoret, and Martinis showed that their macroscopic circuit could escape a “zero-voltage” state via tunnelling, manifesting a measurable voltage.
Moreover, they showed that the circuit absorbed or emitted energy only in discrete amounts—quantisation—mirroring how electrons jump between atomic energy levels. The circuit did not smoothly absorb energy; it did so in packets.
These experiments pushed quantum phenomena out of the purely microscopic realm and into the domain of engineered devices you could grasp.
Why This Prize Matters in Quantum Tunneling
Shifting the Boundary of Quantum Physics
Historically, quantum effects lose coherence when many particles are involved. Interactions with the environment erase the fragile quantum states. But the 2025 Nobel laureates showed that with careful design (superconducting circuits, cryogenic shielding, noise suppression), one can sustain quantum behavior in a system composed of many electrons acting together. This is a landmark in demonstrating that “quantumness” is not strictly limited to the invisible.
Foundation for Quantum Technology
Today’s leading approach to building quantum computers—the superconducting qubit platform—derives directly from the kind of circuits Clarke, Devoret, and Martinis developed. Their experiments provided both theoretical insight and technical roadmaps. The Nobel Committee itself said their work “revealed quantum physics in action … in a system big enough to be held in the hand.”
Their discoveries also uplift related fields: quantum cryptography, quantum sensing, ultra-precise measurement, and fundamental tests of quantum mechanics. The prize thus represents not just past discovery but future potential.
The People Behind the Science in Quantum Tunneling Experiment
John Clarke (University of California, Berkeley) was the mentor and pioneer in superconducting electronics. His earlier work with SQUIDs (superconducting quantum interference devices) already placed him at the frontier of precision experiments.
Michel H. Devoret (Yale, UC Santa Barbara) was the postdoctoral researcher working under Clarke’s guidance. His flair for combining theory and experiment allowed the leap from concept to circuit.
John M. Martinis (UC Santa Barbara, later founder of Qolab) was Clarke’s PhD student. His early collaborations with Devoret and Clarke matured into the designs used in quantum hardware today.
The Quantum Horizon
This Nobel Prize signals that quantum mechanics is no longer an exotic corner of physics, but a toolkit for engineering. The quantum devices of tomorrow—robust qubits, quantum networks, sensors surpassing classical limits—are built upon the groundwork laid by these laureates.
Yet the journey isn’t over: challenges remain in scaling, error correction, and fault tolerance. Maintaining coherence amid noise, expanding from a few qubits to many, and integrating quantum systems with classical infrastructure are frontiers still to cross.
In awarding the prize now, the Nobel Foundation also recognizes that the seeds sown decades ago are flowering into real-world possibility. The quantum tunneling revolution is no longer theoretical—it’s engineering with a twist of strangeness.
