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31.
We investigate a silica-based thulium-doped fibre amplifier, which is a promising candidate for an amplifying device in the S band, in detail using a single wavelength upconversion pumping scheme centred at 1064nm. Our experimental results show that in terms of gain and noise figure, the bi-directional pumping scheme is the best one in the three pumping schemes, named forward, backward and hi-directional pumping schemes. The amplifier has a gain not only in the S band, but also in the C band, even in the L band. The gain is above 3dB from 1525nm to 1580nm with a peak of 7.SdB. 相似文献
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Quantum key distribution(QKD) is a major research topic because it provides unconditional security. Unfortunately, many imperfections remain in QKD's experimental realization. The Faraday–Michelson(FM) QKD system is proposed to eliminate these imperfections using polarization. However, the long arm's phase modulator(PM) has an unexpected insertion loss, meaning that the state sent is no longer perfect. In this letter, we propose an alternative FM-QKD system structure, and analyze the security and key generation rate in comparison with the original system via different analysis methods. We find an obvious key rate improvement when the PM insertion loss is not extremely small. 相似文献
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讨论露天矿生产的车辆调度问题,关键是如何分配和调度现有条件下的电铲和卡车,从而得到一个好的生产计划.通过对问题的进一步分析和合理的简化,根据总定量最小原则及产量最大原则分别建立了相应的动态规划模型.由于模型在解决具体问题过程中的复杂程度和变量、不等式约束条件的个数太多等原因,我们采用逐步优化法对模型作了进一步的改进,然后用LINGO、LINDO等数学软件编程进行模型求解,得到了根据总定量最小原则及产量最大原则下的计划方案. 相似文献
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本文基于提升格式的第 2代小波构造方法 ,建立了区间上的三次B样条小波 ,并用于求解有边界奇异性的微分方程 .由于区间小波的边界特性 ,该方法避免了由小波基引起的振荡 .模拟计算结果验证了所提方法 相似文献
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设计了含有InAs自组装量子点(SAQDs)的新型金属半导体金属隧穿结构,研究了其直流输运特性,观察到了电流迟滞回路现象.这种回路现象是由于紧邻金属肖特基接触的量子点充电和放电引起的,也可以说是由外加电压控制的量子点的单电子过程引起的.分析了量子点总体的充放电特性,量子点中电子在高电场下隧穿出量子点的概率变化决定了量子点的放电过程,而充电过程是由流过量子点层的二极管正向电流决定.理论拟合结果显示充电过程主要由于量子点基态能级俘获电子照成的,激发态对量子点充放电过程只有微弱影响.
关键词:
迟滞现象
自组装量子点
单电子过程 相似文献
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Security of a practical semi-device-independent quantum key distribution protocol against collective attacks 下载免费PDF全文
Similar to device-independent quantum key distribution(DI-QKD), semi-device-independent quantum key distribution(SDI-QKD) provides secure key distribution without any assumptions about the internal workings of the QKD devices.The only assumption is that the dimension of the Hilbert space is bounded. But SDI-QKD can be implemented in a oneway prepare-and-measure configuration without entanglement compared with DI-QKD. We propose a practical SDI-QKD protocol with four preparation states and three measurement bases by considering the maximal violation of dimension witnesses and specific processes of a QKD protocol. Moreover, we prove the security of the SDI-QKD protocol against collective attacks based on the min-entropy and dimension witnesses. We also show a comparison of the secret key rate between the SDI-QKD protocol and the standard QKD. 相似文献
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In the original BB84 quantum key distribution protocol, the states are prepared and measured randomly, which lose the unmatched detection results. To improve the sifting efficiency, biased bases selection BB84 protocol is proposed. Meanwhile, a practical quantum key distribution protocol can only transmit a finite number of signals, resulting in keys of finite length. The previous techniques for finite-key analysis focus mainly on the statistical fluctuations of the error rates and yields of the qubits. However, the prior choice probabilities of the two bases also have fluctuations by taking into account the finite-size effect. In this paper, we discuss the security of biased decoy state BB84 protocol with finite resources by considering all of the statistical fluctuations. The results can be directly used in the experimental realizations. 相似文献