Entanglement-Assisted Entanglement Purification

The efficient generation of high-fidelity entangled states is the key element for long-distance quantum communication, computation and other technologies, at same time most resource-consuming part in many schemes. We present a new class entanglement-assisted entanglement purification protocols that can generate from noisy, finite-size ensembles with improved yield fidelity as compared to previous approaches. scheme utilizes high-dimensional auxiliary perform entangling non-local measurements determine number positions errors an ensemble controlled way, without disturbing good pairs. Our deal arbitrary errors, but are best suited few work particularly well decay noise. methods applicable moderate sized ensembles, will be important near term devices.