[13p-B2-1~12] 3.10 Optical quantum physics and technologies

[13p-B2-6] Experimental generation of GHZ state via a time-resolved coincidence measurement

〇(M2)Nobuo Iwasaki¹, Yoshiaki Tsujimoto¹, Motoki Tanaka¹, Rikizo Ikuta¹, Shigehito Miki², Taro Yamashita², Hirotaka Terai², Takashi Yamamoto¹, Masato Koashi³, Nobuyuki Imoto¹ (1.Osaka Univ., 2.NICT, 3.Univ. of Tokyo)

Keywords:quantum information, quantum optics, quantum communication

We report on the generation of Greenberger-Horne-Zeilinger (GHZ) state using two polarization-entangled photon pairs from spontaneous parametric down conversion pumped by continuous-wave (cw) light via a time-resolved coincidence measurement. When the timing resolution of photon detectors is sufficiently shorter than the coherence time of the photons, the temporal indistinguishability of the photons can be guaranteed by the coincidence detection with such a high timing resolution. In this case, even when the photons are generated by a cw pump laser, post analysis of the timings of the photon detections allows us to select photons having a sufficient temporal overlap. One of the advantages of this method is that there is no need to perform the active synchronizations of the photon sources. We performed the genration of a 3 photon GHZ state in such regime. An observed fidelity to the ideal GHZ state was 0.69.