Mainz 2017 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 24: Quantum Information: Solid State Systems I

Q 24.2: Talk

Tuesday, March 7, 2017, 15:00–15:15, P 3

Phase-controlled entanglement state generation between distant electron spins — •Lukas Huthmacher, Robert Stockill, Megan J. Stanley, Claire Le Gall, Clemens Matthiesen, and Mete Atatüre — Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge UK

Entanglement is one of the fundamental ingredients for the successful realisation of quantum networks and secure communication schemes. Here, we present the first experimental realisation of distant electron spin entanglement in semiconductor quantum dots. In our experiment, the two InGaAs quantum dots are incorporated in a Mach-Zehnder interferometer, allowing for phase-stable excitation and erasure of which path information. Upon detection of a single photon after the second beam-splitter the electron spins are projected into an entangled state [1]. We confirm the creation of entangled states with an average fidelity of 61.6 ± 2.3%, a violation of the classical limit by 5 standard deviations of the mean. We demonstrate active control over the phase of the entangled state through our choice of the interferometer phase. Combining the outstanding photonic properties of self-assembled quantum dots and the minimal heralding scheme we achieve an entanglement generation rate of 7.25 kHz, the highest reported to date.
Cabrillo, C. et al., PRA 59, 1025-1033 (1999)