John Clauser
active c. 1942, Pasadena, California, USA
American physicist, co-author of the CHSH inequality and performer of the first Bell test.
Clauser was captivated by the Einstein–Bohr debate as a Columbia student. In 1969 with Horne, Shimony and Holt he recast Bell's theorem in testable form (CHSH). In 1972 with Stuart Freedman he measured calcium-cascade photon correlations at Berkeley — the first Bell violation, though academia then dismissed it as 'philosophy'.
Nobel-winning work
The CHSH inequality (1969) turned Bell's theorem into an arithmetic prediction: a correlation sum cannot exceed 2 if the universe is 'locally real'. The Clauser–Freedman experiment (1972) measured a value beyond the limit — showing entangled photon pairs defy classical rules, laying the first stone of quantum information science.
Workplaces: University of California, Berkeley
United States