The Nobel Prize in Physics 2025 was awarded 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." The laureates performed experiments on electrical circuits in which they observed quantum mechanical phenomena such as tunnelling and quantised energy levels. Their work showed that quantum tunnelling is not confined to the quantum world, but it can also be reproduced in macroscopic electrical circuits. In recognition of this award, Nature Portfolio presents a collection of research, review and opinion articles that celebrates the contributions by the awardees and the technological advances they have enabled.