Mode-pairing quantum key distribution (MP-QKD) is a potential protocol that is not only immune to all possible detector side channel attacks, but also breaks the repeaterless rate-transmittance bound without needing global phase locking. Here we analyze the finite-key effect for the MP-QKD protocol with rigorous security proof against general attacks. Moreover, we propose a six-state MP-QKD protocol and analyze its finite-key effect. The results show that the original protocol can break the repeaterless rate-transmittance bound with a typical finite number of pulses in practice. And our six-state protocol can improve the secret key rate significantly in long distance cases.
In the past two decades, quantum key distribution networks based on telecom fibers have been implemented on metropolitan and intercity scales. One of the bottlenecks lies in the exponential decay of the key rate with respect to the transmission distance. Recently proposed schemes mainly focus on achieving longer distances by creating a long-arm single-photon interferometer over two communication parties. Despite their advantageous performance over long communication distances, the requirement of phase-locking between two independent lasers is technically challenging. By adopting the recently-p…
Discrete-phase-randomized mode-pairing quantum key distribution
Key Laboratory of Smart Manufacturing in Energy Chemical Process, Ministry of Education, East China University of Science and Technology（教育部智能制造能源化工过程重点实验室，华东理工大学）；College of Electronics and Information Engineering, Tongji University（同济大学电子与信息工程学院）；Shanghai Research Institute for Intelligent Autonomous Systems, Tongji University（同济大学上海智能自动驾驶系统研究院）
Digital signatures can guarantee the unforgeability and transferability of the message. Different from classical digital signatures, whose security depends on computational complexity, quantum digital signatures (QDS) can provide information-theoretic security. We propose a general method of random pairing QDS (RP-QDS), which can drastically improve QDS efficiency. In a way, our random pairing method provide a tightened result of security level of QDS. In the method, the parity value of each pair is used for the outcome bit value. We present general formulas for fraction of untagged bits and e…
Due to the capability of tolerating high error rate and generating more key bits per trial, high-dimensional quantum key distribution attracts wide interest. Despite great progresses in high-dimensional quantum key distribution, there are still some gaps between theory and experiment. One of these is that the security of the secret key heavily depends on the number of the emitted signals. So far, the existing security proofs are only suitable in the case with an infinite or unpractically large number of emitted signals. Here, by introducing the idea of "key classification" and developing relev…
We use a recent numerical security proof approach to calculate tight secure key rates in the presence of collective attacks for a continuous-variable (CV) eight-state phase-shift keying (8PSK) protocol with heterodyne detection in the asymptotic limit. The results are compared to achievable secure key rates of a QPSK protocol obtained with the same security proof technique. Furthermore, we investigate the influence of radial postselection on the secure key rate and examine a recently suggested strategy to reduce the computational requirements on the error-correction phase for four-state phase-…
One of the challenges in practical quantum key distribution is dealing with efficiency mismatch between different threshold single-photon detectors. There are known bounds for the secret key rate for the BB84 protocol with detection-efficiency mismatch provided that the eavesdropper sends no more than one photon to the legitimate receiver. Here we improve these bounds and give tight bounds for the secret key rate with a constant detection-efficiency mismatch under the same single-photon assumption. We propose a method based on the analytical minimization of the relative entropy of coherence, w…
Experimental observation of Higgs oscillations and their power-law decay across pairing regimes in a cavity QED quantum simulator
JILA, NIST and University of Colorado（JILA，美国国家标准与技术研究院和科罗拉多大学）；Department of Physics, University of Colorado（科罗拉多大学物理系）；Pritzker School of Molecular Engineering, University of Chicago（芝加哥大学普里茨克分子工程学院）；Center for Theory of Quantum Matter, University of Colorado（科罗拉多大学量子物质理论中心）；Thomas J. Watson, Sr., Laboratory of Applied Physics, Kavli Nanoscience Institute, and Institute for Quantum Information and Matter, California Institute of Technology（加州理工学院托马斯·J·沃森Sr.应用物理实验室、卡弗里纳米科学研究所和量子信息与物质研究所）
