The 2025 Nobel Prize in Physics was awarded jointly to John Clarke, Michel H. Devoret and John M. Martinis. The Royal Swedish Academy of Sciences announced the prize on 7 October 2025 for “the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit.” The prize amount was 11 million Swedish kronor, to be shared equally among the three laureates.
In 1984 and 1985, the three scientists worked with an electronic circuit built from superconductors. The superconducting components were separated by a thin layer of non-conductive material, a setup known as a Josephson junction. In this circuit, charged particles in the superconductor behaved like one large particle spread across the whole circuit. In quantum mechanics, tunnelling means that a particle can pass through a barrier; in systems with very large numbers of particles, such effects usually become insignificant. The experiments showed that a system large enough to be held in the hand could still display quantum tunnelling by escaping a zero-voltage state, and could absorb or emit only specific amounts of energy. This is the energy quantisation part of the discovery.
For exam preparation, the issue connects Science and Technology, Current Affairs, and awards. Its static-GK links include quantum mechanics, superconductivity, Josephson junctions, quantum computing, quantum sensors and quantum cryptography. RAS Mains 2023 asked a question on differences between classical computing and quantum computing, so this update is useful for prelims facts as well as mains discussion on how basic research can shape next-generation digital technology.