Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 24: Quantum Information: Solid State Systems I
Q 24.1: Group Report
Tuesday, March 7, 2017, 14:30–15:00, P 3
Entanglement purification in an elementary quantum network — •Andreas Reiserer1, Norbert Kalb2, Peter C. Humphreys2, Jacob J. W. Bakermans2, Sten J. Kamerling2, and Ronald Hanson2 — 1Quantum Networks Group, MPI für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching, Germany — 2QuTech and Kavli Institute of Nanoscience Delft, Delft University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands
Entanglement purification facilitates the generation of high-fidelity entangled states from an ensemble of resource states by eradicating a common statistical contamination. This will be essential for the realization of large quantum networks, in which stationary quantum nodes are connected via noisy photonic channels. Here, we show one round of entanglement purification in an elementary quantum network, consisting of two nodes that each contain two qubits. Using two-photon interference, we first generate entanglement between two of the qubits that are formed by the electronic spins of two nitrogen-vacancy centers in diamond at a separation of 2m. The electronic spin state is then transferred to two nuclear spins in close proximity to the NV centers. The resulting entangled nuclear spin state is kept while the electronic spins are entangled again. Then, the purification protocol is completed via local deterministic two-qubit quantum gates, followed by a fluorescence measurement of the electronic spins. Depending on the measurement result, the nuclear spins are projected to an entangled state of higher fidelity than the two raw states. Our results open the door towards the realization of larger quantum networks.