• DOI:10.1103/PhysRevLett.129.050502
• Corpus ID: 247595392

Photonic verification of device-independent quantum key distribution against collective attacks

@inproceedings{Liu2021PhotonicVO,
  title={Photonic verification of device-independent quantum key distribution against collective attacks},
  author={Wen-Zhao Liu and Yu-Zhe Zhang and Yi-Zheng Zhen and Ming-Han Li and Yang Liu and Jingyun Fan and Feihu Xu and Qiang Zhang and Jianwei Pan},
  year={2021}
}

• Wen-Zhao Liu, Yu-Zhe Zhang, +6 authors Jianwei Pan
• Published 4 October 2021
• Physics

The security of quantum key distribution (QKD) usually relies on that the users’s devices are well characterized according to the security models made in the security proofs. In contrast, device-independent QKD — an entanglement-based protocol — permits the security even without any knowledge of the underlying quantum devices. Despite its beauty in theory, device-independent QKD is elusive to realize with current technologies. Especially in photonic implementations, the requirements for detection efficiency are far beyond the performance of any reported device-independent experiments. In this paper, we employ theoretical and experimental efforts and realize a proof-of-principle verification of device-independent QKD based on the photonic setup. On the theoretical side, we enhance the loss tolerance for real device imperfections by combining different approaches, namely, random post-selection, noisy preprocessing, and developed numerical methods to estimate the key rate via the von Neumann entropy. On the experimental side, we develop a high-quality polarization-entangled photon source achieving a state-of-the-art (heralded) detection efficiency about 87 . 5%. This efficiency outperforms previous photonic experiments involving loophole-free Bell tests. Together, we show that the measured quantum correlations are strong enough to ensure a positive key rate under the fiber length up to 220 m. Our photonic platform can generate entangled photons at a high rate and in the telecom wavelength, which is desirable for high-speed generation over long distances. The results present an important step towards a full demonstration of photonic device-independent QKD.