John Martinis
active c. 1958, Denver, Colorado, USA
American physicist, chief engineer of superconducting qubits — led Google to 'quantum supremacy' in 2019.
As Clarke's graduate student at Berkeley, Martinis performed the 1985 experiment demonstrating macroscopic tunneling in Josephson junctions. He then refined phase/Xmon qubits at UCSB before leading Google's hardware team: in 2019 the 53-qubit Sycamore chip completed random-circuit sampling in 200 seconds — estimated to take supercomputers millennia.
Nobel-winning work
The Martinis–Devoret–Clarke experiment (1985) measured the microwave spectrum of a current-biased Josephson junction: discrete energy levels and tunneling escape rates matched quantum mechanics, though the effective 'particle' is the phase of billions of Cooper pairs. It was the first proof that a macroscopic artificial system obeys quantum rules — the technological foundation Martinis later led at Google.
Workplaces: University of California, Santa Barbara, Google Quantum AI
United States