Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 19: Materials and Devices for Quantum Technology 1

HL 19.1: Hauptvortrag

Mittwoch, 7. September 2022, 09:30–10:00, H34

Quantum Interference of Identical Photons from Remote GaAs Quantum Dots — •Giang Nam Nguyen¹, Liang Zhai¹, Clemens Spinnler¹, Julian Ritzmann², Mattias C. Löbl¹, Andreas D. Wieck², Arne Ludwig², Alisa Javadi¹, and Richard J. Warburton¹ — ¹Department of Physics, University of Basel — ²Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum

Efficient generation and detection of coherent single photons are key to advances in photonic quantum technologies such as quantum computation, quantum simulation, and quantum communication. For applications, a significant roadblock is the poor quantum coherence upon interfering single photons created by independent emitters.

Here, we present near-unity two-photon interference visibilities from two separate GaAs quantum dots [1]. This high visibility (~93%) is achieved under rigorous conditions: there is no Purcell enhancement, no temporal post-selection, no narrow spectral-filtering, nor frequency stabilization. Using photons emitted from two remote quantum dots, we demonstrate a photonic CNOT gate. Interfering photons in this quantum logic gate, we generate an entangled two-photon state using photons from separate semiconductor chips. We obtain an entanglement fidelity of (85 +- 1)%, exceeding the CHSH threshold for violating Bell inequalities. This result highlights the importance of the high two-photon visibility for high fidelity entanglement operations.

[1] L. Zhai et al., Nature Nanotechnol. (2022)