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Four Photon Entanglement from Down Conversion

Harald Weinfurter·Marek Zukowski
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Abstract

Double-pair emission from type-II parametric down conversion results in a highly entangled 4-photon state. Due to interference, which is similar to bunching from thermal emission, this state is not simply a product of two pairs. The observation of this state can be achieved by splitting the two emission modes at beam splitters and subsequent detection of a photon in each output. Here we describe the features of this state and give a Bell theorem for a 4-photon test of local realistic hidden variable theories.

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Harald Weinfurter, Marek Zukowski. 2001-03-09. Four Photon Entanglement from Down Conversion. https://doi.org/10.1103/physreva.64.010102

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