John Clarke
active c. 1942, Cambridge, England
British-American physicist, pioneer of SQUIDs and proof that macroscopic Josephson systems behave quantum-mechanically.
Clarke built at Berkeley the world's most sensitive SQUIDs — superconducting Josephson junction devices measuring the brain's and earth's faintest magnetic fields. In 1984–85, with Michel Devoret and John Martinis, he showed 'macroscopic' superconducting circuits possess quantized energy states and tunnel like nuclei — opening the way to superconducting qubits.
Nobel-winning work
The 2025 Nobel honored 'the discovery of macroscopic quantum tunneling and energy quantization in electric circuits': Clarke's group proved the Josephson phase of billions of Cooper pairs behaves as a single quantum 'particle' — discrete energy levels escaping through a potential barrier — showing quantum mechanics works at printed-circuit scale, the basis of superconducting quantum computers.
Workplaces: University of California, Berkeley
United Kingdom, United States