All-optical quantum computation, step 1: A controlled-NOT photonic gate

(PhysOrg.com) — The often counterintuitive quantum world of superposition, entanglement, and tunneling can greatly enhance applications as diverse as communication, information processing, and precision measurement. At the same time, photons have the equally attractive properties of low noise, light speed transmission, and ease of manipulation using conventional optics. However, due to the probabilistic nature of single photons, the two have never been integrated into a single system – until now.

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All-optical quantum computation, step 1: A controlled-NOT photonic gate