Functional quantum circuit combines photon gates
Shigeki Takeuchi · SPIE Newsroom · 2009
An optical-quantum-circuit entanglement filter can pass a pair of pho-tons with the desired polarization correlations. Photons are an important information-conveyance medium for enhanced computers and communications based on quantum mechanics. Filtering multiple photon states is a key capabili-ty in quantum-information science and technology, where one-quantum binary-digit (one-qubit) filters, or polarizers, have found wide application. Filtering based on the correlation or en-tanglement of photons requires multi-qubit filters with qubit-qubit interactions. We demonstrate an optical-entanglement filter that passes a pair of photons if they have the desired polarization correlations.1 The entangling capability of the filter was verified, distinguishing it from classical ones. Because our entanglement filter acts on photonic qubits, it is promising for quantum tech-