The Nobel Prize in Physics 2025 has been awarded to John Clarke, Michel H. Devoret, and John M. Martinis for their “discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit.” The laureates’ research demonstrated that quantum mechanical properties, typically observed on a microscopic scale, can be made concrete in a macroscopic system.
The researchers conducted a series of experiments using a superconducting electrical circuit with a Josephson junction, a component in which two superconductors are separated by a thin insulating barrier. The system, composed of a vast number of charged particles, behaved as a single quantum mechanical particle, demonstrating two quantum behaviors: it escaped a zero-voltage state through tunneling (a process called macroscopic quantum tunnelling or MQT), and it absorbed or emitted specific, quantized amounts of energy.
This research provided a foundation for the next generation of quantum technology, including quantum computers and quantum sensors. John M. Martinis later used a similar circuit with quantized states as an information-bearing unit, or quantum bit, in a quantum computer experiment. This work established superconducting circuits as a possible platform for qubits.
The discoveries have consequences for the theoretical understanding of quantum mechanics. The laureates’ macroscopic quantum system, composed of many Cooper pairs, is a form of artificial atom on a large scale. Theorists like Anthony Leggett, who was awarded the Nobel Prize in Physics in 2003 for his theoretical work on macroscopic quantum tunnelling, have compared the laureates’ macroscopic quantum system with Erwin Schrödinger’s famous thought experiment.
Read the full announcement from the Royal Swedish Academy of Sciences here and popular information from NobelPrize.org here, and the scientific background to the prize here.
October 7, 2025
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