John Clauser Created 2026-10-24 Updated 2026-11-05
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John Clauser and Stuart Freedman tested local hidden-variable theories with photons from a calcium atomic cascade. They measured joint detections behind differently oriented polarizers and compared a combination of those rates with a Bell inequality. The observed violation agreed with quantum mechanics, turning assumptions about distant outcomes into a quantitative laboratory test. The experiment used additional assumptions about detection and the sampled photon pairs; it did not close every later-identified experimental loophole.[ref]
A physicist who performed experimental tests of Bell inequalities.[ref]
Figure 1.
Portrait of John Clauser
. Peter Lyons, photograph; Adem, existing portrait crop. CC BY-SA 4.0, via Wikimedia Commons. Source.
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Stuart Freedman Created 2026-10-24 Updated 2026-11-05
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Stuart Freedman and John Clauser measured polarization correlations between pairs of photons emitted in a calcium atomic cascade. Comparing coincidence rates at different polarizer orientations allowed them to test a Bell inequality adapted to their apparatus; the 1972 results agreed with quantum mechanics. Their measurement made a foundational question experimentally concrete, while its interpretation retained assumptions concerning the detected sample and optical efficiencies.[ref]
A physicist who researched nuclear physics and experimentally tested Bell inequalities.[ref]
Figure 1.
Portrait of Stuart Freedman
. Lawrence Berkeley National Laboratory (Commons author field and photoarchive source). CC BY-SA 4.0, via Wikimedia Commons. Source.
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