Ou Raadsaal Ou Raadsaal The Ou Raadsaal (English: "Old Council Hall") is a historic building in Pretoria, South Africa, located on the south side of Church Square. The Ou Raadsaal housed the Volksraad, the parliament of the South African Republic, from 1891 to 1902. The Ou Raadsaal was commissioned in the late 19th century by the South African Republic as the new seat of government in Pretoria, and was designed by Dutch architect Sytze Wierda in a Renaissance Revival style. The contract for construction was granted to John Johnstone Kirkness, a builder from the Orkney Islands with a prolific building career in
Hong–Ou–Mandel effect dip is related to the states of the two photons formula_14 and formula_15 as If formula_17, then the visibility is equal to the purity formula_18 of the photons. In 2006, an experiment was performed in which two atoms independently emitted a single photon each. These photons subsequently produced the Hong–Ou–Mandel effect. The Hong–Ou–Mandel effect also underlies the basic entangling mechanism in linear optical quantum computing, and the two-photon quantum state formula_19 that leads to the HOM dip is the simplest non-trivial state in a class called NOON states. In 2015 the Hong–Ou–Mandel effect for photons was directly observed with spatial