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arXiv · 1612.07483

High-fidelity entanglement swapping and generation of three-qubit GHZ state using asynchronous telecom photon pair sources

Yoshiaki Tsujimoto·Motoki Tanaka·Nobuo Iwasaki·Rikizo Ikuta·Shigehito Miki·Taro Yamashita·Hirotaka Terai·Takashi Yamamoto·Masato Koashi·Nobuyuki Imoto
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Abstract

We experimentally demonstrate a high-fidelity entanglement swapping and a generation of the Greenberger-Horne-Zeilinger~(GHZ) state using polarization-entangled photon pairs at telecommunication wavelength produced by spontaneous parametric down conversion with continuous-wave pump light. While spatially separated sources asynchronously emit photon pairs, the time-resolved photon detection guarantees the temporal indistinguishability of photons without active timing synchronizations of pump lasers and/or adjustment of optical paths. In the experiment, photons are sufficiently narrowed by fiber-based Bragg gratings with the central wavelengths of 1541~nm and 1580~nm, and detected by superconducting nanowire single-photon detectors with low timing jitters. Observed fidelities are 0.84 \pm 0.04 and 0.70 \pm 0.05 for the entanglement swapping and generation of the GHZ state, respectively.

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Yoshiaki Tsujimoto, Motoki Tanaka, Nobuo Iwasaki, Rikizo Ikuta, Shigehito Miki, Taro Yamashita, Hirotaka Terai, Takashi Yamamoto, Masato Koashi, Nobuyuki Imoto. 2016-12-22. High-fidelity entanglement swapping and generation of three-qubit GHZ state using asynchronous telecom photon pair sources. https://doi.org/10.1038/s41598-018-19738-8

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