Twin-Field quantum key distribution (TF-QKD) and its variants, e.g. Phase-Matching QKD, Sending-or-not-sending QKD, and No Phase Post-Selection TFQKD promise high key rates at long distance to beat the rate distance limit without a repeater. The security proof of these protocols are based on decoy-state method, which is usually performed by actively modulating a variable optical attenuator together with a random number generator in practical experiments, however, active-decoy schemes like this may lead to side channel and could open a security loophole. To enhance the source security of TF-QKD, in this paper, we propose passive-decoy based TF-QKD, in which we combine TF-QKD with the passive-decoy method. And we present a simulation comparing the key generation rate with that in active-decoy, the result shows our scheme performs as good as active decoy TF-QKD, and our scheme could reach satisfactory secret key rates with just a few photon detectors. This shows our work is meaningful in practice.

中文翻译：

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具有被动诱饵状态的双域量子密钥分发

双场量子密钥分发 (TF-QKD) 及其变体，例如相位匹配 QKD、发送或不发送 QKD 和无相位后选择 TFQKD 承诺远距离高密钥速率以超过速率距离限制没有中继器。这些协议的安全性证明基于诱饵状态方法，在实际实验中通常通过主动调制可变光衰减器和随机数发生器来实现，然而，像这样的主动诱饵方案可能会导致侧信道并可能打开安全漏洞。为了增强 TF-QKD 的源安全，在本文中，我们提出了基于被动诱饵的 TF-QKD，其中我们将 TF-QKD 与被动诱饵方法相结合。我们提出了一个模拟，将密钥生成率与主动诱饵中的密钥生成率进行比较，结果表明我们的方案与主动诱饵 TF-QKD 一样好，我们的方案只需几个光子探测器就可以达到令人满意的密钥率。这说明我们的工作在实践中是有意义的。