Chun-Mei Zhang

Improved statistical fluctuation analysis for measurement-device-independent quantum key distribution with four-intensity decoy-state method

We present an improved statistical fluctuation analysis for measurement device independent quantum key distribution with three-intensity decoy-state method. Taking the statistical fluctuations for different sources jointly, we present more tightened formulas for some key quantities used in calculating the secure final key. Numerical simulation shows that, given the total number of pulses

Biased decoy-state reference-frame-independent quantum key distribution

10^{12}

Decoy-state reference-frame-independent quantum key distribution with both source errors and statistical fluctuations

, our method improves the key rate by about 97\% for a distance of 50kms compared with the result given by Xu., et al. (Phys. Rev. A 89, 052333); and improves the key rate by

Decoy-state reference-frame-independent quantum key distribution with the single-photon-added coherent source

146\%

Improved statistical fluctuation analysis for measurement-device-independent quantum key distribution

for a distance of 100kms compared with the result from full optimization of all parameters but treating the statistical fluctuations traditionally, i.e., treating the fluctuations for different sources separately.

Biased three-intensity decoy-state scheme on the measurement-device-independent quantum key distribution using heralded single-photon sources

Abstract Reference-frame-independent quantum key distribution (RFI-QKD) can generate secure keys even when the reference frames drift slowly. Here, we propose a new scheme on the decoy-state RFI-QKD, where the basis assignments of two legitimate parties are biased, reducing the fraction of mismatched-basis data. Considering statistical fluctuations under different misalignments of reference frames, we originally investigate the performance of biased decoy-state RFI-QKD with full parameter optimization. We also make a clear comparison between the new scheme with other practical schemes, e.g., unbiased decoy-state RFI-QKD and biased decoy-state BB84-QKD. Simulation results demonstrate that, the new proposed biased decoy-state RFI-QKD can significantly improve the performance (secret key rate and secure transmission distance), which shows great potential in real-life QKD systems. Graphical abstract

Passive decoy-state quantum key distribution with the SARG04 protocol

Reference-frame-independent quantum key distribution (RFI QKD) can generate secret keys without the alignment of reference frames, which is very robust in real-life implementations of QKD systems. However, the performance of decoy-state RFI QKD with both source errors and statistical fluctuations is still missing until now. In this paper, we investigate the performance of decoy-state RFI QKD in practical scenarios with two kinds of light sources, the heralded single photon source (HSPS) and the weak coherent source (WCS), and also give clear comparison results of decoy-state RFI QKD with WCS and HSPS. Simulation results show that the secret key rates of decoy-state RFI QKD with WCS are higher than those with HSPS in short distance range, but the secret key rates of RFI QKD with HSPS outperform those with WCS in long distance range.

Improving the Performance of Practical Decoy-State Measurement-Device-Independent Quantum Key Distribution with Biased Basis Choice

Reference-frame-independent quantum key distribution (RFI-QKD) can generate secure keys even when the reference frames drift slowly. Here, we propose to realize RFI-QKD with the single-photon-added coherent source (SPACS). Simulation results show that compared with the weak coherent state and the heralded single-photon source, SPACS can remarkably improve the key generation rate and transmission distance of RFI-QKD. Moreover, our results show the significance of optimized parameters. When taking statistical fluctuations into consideration, RFI-QKD with SPACS can still achieve very good performance.

Parameter optimization in biased decoy-state quantum key distribution with both source errors and statistical fluctuations

Measurement-device-independent quantum key distribution (MDI-QKD) is a promising protocol for realizing long-distance secret keys sharing. However, its key rate is relatively low when the finite-size effect is taken into account. In this paper, we consider statistical fluctuation analysis for the three-intensity decoy-state MDI-QKD system based on the recent work (Zhang et al. in Phys Rev A 95:012333, 2017) and further compare its performance with that of applying the Gaussian approximation technique and the Chernoff bound method. The numerical simulations demonstrate that the new method has apparent enhancement both in key generation rate and transmission distance than using Chernoff bound method. Meanwhile, the present work still shows much higher security than Gaussian approximation analysis.

Implementing full parameter optimization on decoy-state measurement-device-independent quantum key distributions under realistic experimental conditions

At present, most of the measurement-device-independent quantum key distributions (MDI-QKD) are based on weak coherent sources and limited in the transmission distance under realistic experimental conditions, e.g., considering the finite-size-key effects. Hence in this paper, we propose a new biased decoy-state scheme using heralded single-photon sources for the three-intensity MDI-QKD, where we prepare the decoy pulses only in X basis and adopt both the collective constraints and joint parameter estimation techniques. Compared with former schemes with WCS or HSPS, after implementing full parameter optimizations, our scheme gives distinct reduced quantum bit error rate in the X basis and thus show excellent performance, especially when the data size is relatively small.