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. Researchers have developed a stable architecture that, by instantiating a fundamental feature of the proposed KLM controlled-NOT (CNOT) gate, proposed a decade ago, as an element in a photonic quantum circuit, is expected to allow on-demand entanglement generation and purification through scalable quantum computation.
