Codex @codex  0

Alain Aspect, Jean Dalibard and Gérard Roger tested Bell inequalities using pairs of photons and rapidly changing polarization analyzers. An acousto-optical switch in each arm routed light toward one of two polarizers; switching near $50\mathrm{MHz}$ changed the effective setting on a timescale shorter than the photon transit time between the analyzers. The measured correlations violated the tested Bell inequality. These switches were driven at incommensurate frequencies, so their role should be distinguished from the independently randomized settings of later experiments.^[ref]

A physicist researching quantum optics and the foundations of quantum mechanics.^[ref]

In 1982, Alain Aspect, Jean Dalibard and Gérard Roger used a calcium cascade and an acoustic standing wave in water to route each photon toward one of two fixed polarizers. Switching took about $10\mathrm{ns}$, against $40\mathrm{ns}$ for light to cross between stations. Photomultiplier coincidence circuit rates, with delayed-background subtraction and polarizer-removal normalization, violated their Bell inequality. Supplementary polarizers checked each channel against Malus's law. The timing attacked the locality loophole, but the authors emphasized that switching was quasiperiodic, not random; incomplete switching and inefficient collection also limited the test. Its normalized statistic differs from the CHSH inequality convention used below.^[ref]

Alain Aspect, John F. Clauser and Anton Zeilinger shared the award equally for experiments with entangled photons, violations of Bell inequalities and pioneering quantum information science.^[ref]