Passive scheme with a photon-number-resolving detector for monitoring the untrusted source in a plug-and-play quantum-key-distribution system

A passive scheme with a beam splitter and a photon-number-resolving (PNR) detector is proposed to verify the photon statistics of an untrusted source in a plug-and-play quantum-key-distribution system by applying a three-intensity decoy-state protocol. The practical issues due to statistical fluctuation and detection noise are analyzed. The simulation results show that the scheme can work efficiently when the total number of optical pulses sent from Alice to Bob is above 10^8, and the dark count rate of the PNR detector is below 0.5 counts/pulse, which is realizable with current techniques. Furthermore, we propose a practical realization of the PNR detector with a variable optical attenuator combined with a threshold detector.Comment: 8 pages, 6 figure

Linguistic Landscape of China: A Case Study of the Language Use of Shop Signs in Wuhan

This study with a focus on the shop signs of Wuhan, investigates the linguistic landscape in China. By taking and processing photos of 147 commercial shops, it aims to analyze the language use of shop signs in Han Street, Wuhan, China and provides feasible explanations for such language choice from three new perspectives, namely commercial drive, English as lingua franca and current Chinese language policy.

Pricing Moving Window Parisian Option and Applications in Convertible Bonds

AbstractParisian options are complex path-dependent options developed by barrier option. Moving window Parisian options are higher path-dependent options, which are widely used in the field of convertible bonds in recent years. In this work we propose to price moving window Parisian option by use of hitting time. A simulation algorithm of the pricing is presented. As an application, we provide the pricing equations of convertible bonds with reset clause. Furthermore our simulation method is applied to price convertible bonds with reset clause using the data in China mainland stock exchange. The results show that this algorithm can undoubtedly improve the accuracy of the convertible bonds pricing

Source monitoring for continuous-variable quantum key distribution

The noise in optical source needs to be characterized for the security of continuous-variable quantum key distribution (CVQKD). Two feasible schemes, based on either active optical switch or passive beamsplitter are proposed to monitor the variance of source noise, through which, Eve's knowledge can be properly estimated. We derive the security bounds for both schemes against collective attacks in the asymptotic case, and find that the passive scheme performs better.Comment: The first version. 9 pages and 4 figure