Quantum Experiments That Reached a Human Scale

John Clarke, Michel H. Devoret and John M. Martinis were awarded the 2025 Nobel Prize in Physics for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit, a finding that blurred the boundary between atomic and human scales. In experiments carried out in the mid-1980s they built superconducting circuits containing Josephson junctions, and by measuring currents and voltages they showed that a large, collective electrical system could escape a zero-voltage state through quantum tunnelling. The same work also revealed discrete energy levels when microwaves were applied, demonstrating that energy was absorbed in specific quanta rather than continuously.

If a macroscopic system is kept extremely cold and isolated, quantum effects can dominate its behaviour; this is precisely what the laureates achieved, and it is why their work has been central to the development of superconducting qubits. Nevertheless, practical quantum computers emerged only after decades of engineering to reduce noise and loss, and consequently researchers have relied on the foundational measurements made in these early studies. Moreover, because the experiments were scalable and repeatable, they have informed designs for sensors and components that exploit quantum coherence.

The prize was announced on 7 October 2025 and the laureates, who are connected to University of California, Berkeley; Yale University; and University of California, Santa Barbara, will share 11 million Swedish kronor. Were these circuits studied in a different era, their technological importance might not have been appreciated; today, however, the lineage from lab demonstrations to commercial research is clear, and many teams worldwide pursue variations of the same superconducting approach. While fundamental questions about decoherence remain, the awarded discovery remains a landmark that has reshaped both basic physics and the road toward quantum technologies.