SRRS对强激光下行传输的影响

本文从包括自发和受激Raman散射在内的基本微分方程出发,导出其在大气传输中的积分解,并在标准大气模型下,计算讨论了各种条件的下行传输阈值。     

关于序列覆盖s映射

本文定义了两类序列覆盖映射，讨论了度晴空间的序列覆盖ｓ映象，特别地，我们证明了空间Ｘ具有点可数弱当且仅当Ｘ是度量空间的１序列覆盖的商ｓ映象，这回答了１９７０年Ｔ．Ｈｏｓｈｉｎａ提出了一个问题。     

A note on closed images of locally compact metric spaces

Summary A decomposition theorem about closed images of locally compact metric spaces is discussed. It is shown that a space is a closed image of a locally compact metric space if and only if it is a regular Fréchet space with a point-countable k-network, and each of its closed first-countable subset is locally compact.     

Pricing and effort investment for a newsvendor-type product

We investigate a dominant retailer’s optimal joint strategy of pricing and timing of effort investment and analyze how it influences the decision of the manufacturer, the total supply chain profit, and the consumers’ payoff. We consider two pricing schemes of the retailer, namely, dollar markup and percentage markup, and two effort-investment sequences, namely, ex-ante and ex-post. A combination of four cases is analyzed. Our results show that: (1) under the same effort-decision sequence, a percentage-markup pricing scheme leads to higher expected profit for the retailer and the whole supply chain, but a lower expected profit for the manufacturer and a higher retail price for the consumers; (2) under the same markup-pricing strategy, the dominant retailer always prefers to postpone her effort decision until the manufacturer makes a commitment to wholesale price, since it can result in a Pareto-improvement for all the supply chain members. That is, the retailer’s and manufacturer’s expected profits are higher and the consumers pay a lower retail price; and (3) among the four joint strategies, the dominant retailer always prefers the joint strategy of percentage-markup plus ex-post effort decision. However, the dominated manufacturer always prefers the joint strategy of dollar-markup plus ex-post effort decision, which is also beneficial to the end consumers.     

Scheme for Implementing an N-Qubit Phase Gate via Selective Atom--Field Interaction with Cavity Quantum Electrodynamics

A scheme for implementing a two-qubit phase gate with atoms sent through a high-Q optical cavity is proposed by choosing nonidentical coupling constants between the atoms and cavity. The atomic spontaneous emission can be suppressed due to the large atom-field detuning. Moreover, the scheme can be generalized to implement an N-qubit phase gate and the gating time does not change with an increase of the number of qubits.     

Intrinsic Decoherence of a Two-Atom System with Dipole--Dipole

We investigate the effect of dipole-dipole interaction on the intrinsic decoherence of a system which consists of two two-level atoms and an optical cavity. The entanglement of the system is calculated by making use of concurrence. Our results show that the appropriate choice for the coupling constant Ω of dipole-dipole interaction can restrain the intrinsic deeoherenee of the system. We also find a special phenomenon. No matter what the value of γ is, the concurrence of system slowly increases and cannot exceed 0.71 when Ω= 1.     

Application of Cosine Zone Plates to Image Encryption

We analyse the diffraction result of optical field after Cosine zone plate, and theoretically deduce its transform matrix. Under some conditions, its diffraction distribution is a mixture of fractional Fourier spectra. Then we use Cosine zone plate and its diffraction result to image encryption. Possible optical image encryption and decryption implementations are proposed, and some numerical simulation results are also provided.     

概率远程制备多粒子GHZ纠缠态

利用一个(N 1)粒子部分纠缠Greenberger-Home-Zeilinger(GHZ)态作为量子通道,提出了概率远程制备N粒子GHZ态的两个方案.我们考虑了怎样远程制备一个任意的GHZ态,即两个参数α和β都是复数的情况.此外,计算了远程制备总的成功概率和需要的经典信息量.     

利用单光子的量子对话

提出了一个利用一束单光子对话的方案.在方案中,利用两个不同的幺正操作对光子态进行编码,并且从一束光子中选择较大的子集进行窃听检查,该方案能够有效地抵御截取再发送袭击.此外,由于利用单光子没有利用EPR对,因此该方案是很实际的.该方案是绝对安全的.