量子通信研究进展与应用

量子通信利用量子信道进行信息的编码、传输和处理,具有安全性高和信道容量高等特点。量子保密通信以信息安全为主要目的,包括量子密钥分发、量子安全直接通信和量子秘密共享等模式。利用量子纠缠,量子隐形传态根据事先已经分发的纠缠粒子对实现不传输实物粒子而传输未知粒子的状态,量子密集编码通过传输一个粒子而实现两个粒子信息的传输,这些是经典通信无法实现的任务。文章简单介绍量子通信的内容和进展情况。     

Deterministic Quantum Key Distribution with Pulsed Homodyne Detection

In this paper, we propose a deterministic quantum communication protocol using weak coherent states and pulsed homodyne detection. In this protocol, the communication parties exchange their secret information deterministicaJly in two rounds. The devices and efficiency of the protocol are discussed respectively. We also show the security of the protocol against intercept-resend and Trojan-Horse eavesdropping attacks.     

基于N个有序纠缠光子对的量子机密共享方案

提出了一种基于N个有序纠缠光子对量子机密共享方案.用纠缠光子作为信息的载体,密钥管理者Alice将纠缠光子对分成两个序列,其中一个序列直接发送给合作者之一Bob,在确保第一个序列发送安全后,再对第二个序列进行编码,发送给另一个合作者Charlie.Bob和Charlie分别对他们所接收到的光子序列进行Bell基联合测量...     

一种具有吸波和相位相消特性的共享孔径雷达吸波材料

提出了共享孔径雷达吸波材料(shared aperture radar absorbing material,SA-RAM)的设计方法.该方法将无源人工电磁媒质(metamaterials,MTM)的散射问题等效为有源阵列的辐射问题进行研究,利用阵列天线原理对有限周期MTM单元构成的MTM子孔径的位置信息、幅度信息、相位信息进行优化设计,实现具有不同功能的SA-RAM.在此基础上,设计了一种基于人工磁导体(artificial magnetic conductor,AMC)子孔径和完美吸波体(perfect metamaterial absorber,PMA)子孔径的SA-RAM,该SA-RAM通过将AMC子孔径与PMA子孔径交错布阵,实现了具有吸波和相位相消特性的SA-RAM.仿真和实验结果表明,该SA-RAM较金属板的后向雷达散射截面(radar cross section,RCS)在5.5—8.3 GHz都有明显的减缩,在5.54 GHz处的减缩是由于PMA的高吸波率引起的,在7.0 GHz处的减缩是由于AMC子孔径和PMA子孔径相位相消引起的.研究结果对频域和空域隐身相结合的雷达吸波材料设计具有重要的指导意义.     

两种渠道进入模式下信息获取与分享策略研究

考虑单制造商和单零售商组成的双渠道供应链,基于随机需求建立制造商可以在零售商确定订货量之前(先进模式)或与零售商同时(同进模式)确定直销渠道订货量、零售商可通过支付固定成本来获取真实市场需求的订货量博弈模型。首先在两种模式下研究了零售商愿意获取信息并分享给制造商的条件,结果表明当获取成本较高时,零售商不会获取信息;否则零售商会获取信息但不分享给制造商,此时制造商可通过成本分担和信息价值补贴合约来实现双方利润的帕累托改进。随后讨论了渠道进入模式选择策略,结果表明制造商总是选择先进模式,而只要需求的变异系数不是很小,同进模式对零售商更有利。     

Dominant wing spectroscopy of energy pooling collisions near the boundary layer involving thermal caesium vapour

We have observed the dominant wing spectroscopy of energy pooling collision near the boundary layer involving Cs atoms under the condition of moderate-to-high optical depths at line-centre. It appears from our experimental investigations that the energy-pooling fluorescence presents about 16 spectral lines, and all the lines can be assigned to the Cs atomic transitions. We find that all lines of the energy-pooling retrofluorescence from the heated Cs atomic vapour cell show two-peak profiles. In addition, its pumping power linear dependence in the energy pooling process has been measured and analysed.     

一种基于双偏振分束器的量子秘密共享方案

提出一个基于双偏振分束器的单量子比特全光纤量子秘密共享方案, 该方案具有自动补偿光纤及光学器件的双折射效应和相位抖动的功能, 在干涉对比度测试和稳定性测试时, 该方案在5 km通信距离中, 获得的干涉对比度优于993%, 且可长时间保持稳定. 关键词： 量子秘密共享 偏振分束器 单光子干涉     

电流串联双调压喷嘴试验台测控系统设计

喷嘴是发动机推进室的重要组成元件,通过研究其工作原理,根据流量特性检测需求,设计了一套集硬件线路设计和工艺采集于一体的喷嘴试验台测控系统。针对系统电路进行改造,利用信号传输特性设计了电流串联回路,解决了传感器重复使用的问题。建立以太网通信,利用Labview创建共享变量调用PLC数据,设计了阶梯式双调压采集系统,提高了试验工况和参数采集的精度。实验表明,系统可以通过上位机界面实现信号的实时采集以及数据处理、记录与分析等功能,试验工况误差达到1%。     

Threshold Quantum Secret Sharing of Secure Direct Communication

We propose a （L, n）-threshold quantum secret sharing protocol of secure direct communication following some ideas of Zhang＇s protocol [Phys. Lett. A 342 （2005） 60] and Tokunaga et al.＇s protocol [Phys. Rev. A 71 （2005） 012314]. The sender distributes the classical secret shares to his or her n agents and each agent owns a secret share in advance. The sender＇s secure direct communication message can be extracted by an agent subset by collaboration in such a way that at least t or more agents can obtain the secret message with the mutual assistances but any t - 1 or fewer agents cannot. In contrast to the previous multiparty quantum secret sharing protocols in which the sender＇s secret message can be recovered only if all the agents collaborate, our protocol is more practical and more flexible.     

Charge sharing effect on 600 μm pitch pixelated CZT detector for imaging applications

We are currently investigating the spatial resolution of highly pixelated Cadmium Zinc Telluride （CZT） detector for imaging application. A 20 mm × 20 mm× 5 mm CZT substrate was fabricated with 600 μm pitch pixels （500μm anode pixels with 100 μm gap） and coplanar cathode. Charge sharing between two pixels was studied using collimated a 122 keV gamma ray source. Experiments show a resolution of 125 μm FWHM for double-pixel charge sharing events when the 600 μm pixelated and 5 mm thick CZT detector biased at -1000 V. In addition, we analyzed the energy response of the 600 μm pitch pixelated CZT detector.