Quantum Experiments That Reached a Human Scale

John Clarke, Michel H. Devoret and John M. Martinis won the 2025 Nobel Prize in Physics for work that demonstrated quantum behaviour in a circuit large enough to be handled. The award recognises their work on macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit. In the mid-1980s they built superconducting circuits with Josephson junctions. Those experiments have shown that a system composed of many particles can behave like a single quantum particle, although that behaviour was once thought to be limited to atoms.

While the system was kept cold and isolated, its state was measured by changing currents and detecting voltage jumps. The phenomena have been observed and quantified; energy levels were seen when microwaves were added. Since then, these results have underpinned efforts to make superconducting qubits for quantum computers. The experiments were done at labs linked to the laureates' universities.

The award was announced on 7 October 2025 and the prize money totals 11 million Swedish kronor to be shared. The three laureates are connected to University of California, Berkeley; Yale University; and University of California, Santa Barbara. Their work has been central to later developments in quantum computing and sensing.