Jian-Rong Zhu

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

The enhanced measurement-device-independent quantum key distribution with two-intensity decoy states

10^{12}

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

, 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 both source errors and statistical fluctuations

146\%

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

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.

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

We put forward a new scheme for implementing the measurement-device-independent quantum key distribution (QKD) with weak coherent source, while using only two different intensities. In the new scheme, we insert a beam splitter and a local detector at both Alice’s and Bob’s side, and then all the triggering and non-triggering signals could be employed to process parameter estimations, resulting in very precise estimations for the two-single-photon contributions. Besides, we compare its behavior with two other often used methods, i.e., the conventional standard three-intensity decoy-state measurement-device-independent QKD and the passive measurement-device-independent QKD. Through numerical simulations, we demonstrate that our new approach can exhibit outstanding characteristics not only in the secure transmission distance, but also in the final key generation rate.

An improved proposal on the practical quantum key distribution with biased basis

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

Practical decoy-state reference-frame-independent measurement-device-independent quantum key distribution

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.

Decoy-State Reference-Frame-Independent Measurement-Device-Independent Quantum Key Distribution With Biased Bases

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.

Practical reference-frame-independent quantum key distribution systems against the worst relative rotation of reference frames

The decoy-state method has been widely used in commercial quantum key distribution (QKD) systems. In view of the practical decoy-state QKD with both source errors and statistical fluctuations, we propose a universal model of full parameter optimization in biased decoy-state QKD with phase-randomized sources. Besides, we adopt this model to carry out simulations of two widely used sources: weak coherent source (WCS) and heralded single-photon source (HSPS). Results show that full parameter optimization can significantly improve not only the secure transmission distance but also the final key generation rate. And when taking source errors and statistical fluctuations into account, the performance of decoy-state QKD using HSPS suffered less than that of decoy-state QKD using WCS.