一些损失估计的不可容许性结果

在协方差阵为σ~2V的正态线性模型下,本文对任给定的正整数k证明了基于σ~k的一致最小方差无偏估计和最优仿射同变估计的通常损失估计是不可容许的.此处σ>0未知,V已知.本文还导出了一些关于Γ函数的不等式,被用来证明前述结果.     

粒子数压缩态光场参与的和频过程

本文研究粒子压缩态光场参与的和频过程中各输出的光场的量子统计特性。我们导出各输出光场和总输出光场的归一化量子噪声（Ｆａｎｏ因子）随有效相互作用长度而变化的规律，发现非线性光学过程输入场的量子噪声变大，使和频光场的量子噪声变小，显示输入光场的统计性质的特点部分地转移和频光场。     

高电荷态离子207Pbq+(24≤q≤36)与Si(110)固体表面作用的电子发射研究

报道了利用兰州重离子加速器国家实验室ECR源引出的高电荷态离子²⁰⁷Pb^q+(24≤q≤36)入射到Si(110)表面产生的电子发射的实验测量结果.结果表明,高电荷态离子与固体表面相互作用产生的电子发射产额Y与入射离子的电荷态q、入射角度ψ和入射能量E都有很强的关联.首次发现,电子发射产额Y与入射角度ψ间有接近1/tanψ的关系.理论分析认为,这些过程与基于经典过垒模型的势能电子发射过程密切相关. 关键词： 高电荷态离子 经典过垒模型 电子发射产额     

Quantum Fluctuation of Mesoscopic Capacitance Coupled Circuit in a Thermal Vacuum State

The quantum fluctuations of mesoscopic capacitance-coupled circuit in thermal vacuum state are investigated by using the theory of thermal field dynamics on the basis of quantization of the mesoscopic circuit. It is shown that under a definite temperature, the fluctuations of electric charges and currents change with temperature. The higher the temperature, the more quantum noise the coupled circuit exhibits.     

第Ⅰ种非对称三态叠加多模叠加态光场的高次和压缩--第一正交分量的N次方H压缩效应

构造了第孙中禹种强度不等的非对称三态叠加多模叠加态光场|ψ1(ABC)〉q.利用多模压缩态理论研究了态|ψ1(ABC)〉q第一正交分量高次和压缩.结果发现:①当构成态|ψ1(ABC)〉q的三个多模相干态光场的强度不相等时,在一定条件下,态|ψ1(ABC)〉q的第一正交分量可出现任意幂次的高次和压缩.②当上述的三个多模相干态光场强度相等时,态|ψ1(ABC)〉q的第一正交分量的高次和压缩现象消失.在这种情况下,态|ψ1(ABC)〉q的第一正交分量恒处于NH最小测不准态.     

随机过程的阈交方法在分析股票涨跌周期中的应用

提出了运用随机过程的阈交方法来分析股票的平均涨跌周期,用实例得到了中国石化(600028)股票的平均涨跌周期为2天.并提出了中国股市的日涨跌幅限制在7%的想法,用实例说明了这种想法的合理性.     

Generation of Two-Atom Cluster State via Cavity QED

We propose a physical scheme for generating a two-atom cluster state through the simultaneous interaction of two two-level atoms with a single-mode cavity field prepared initially in an odd-coherent state under a large-detuned limit. The influence of the dissipation constant, the intensity of the field and the imperfect manipulation on the preparation scheme are investigated. It is shown that when the intensity of the cavity is large enough, the influence of the cavity decay is ettlciently suppressed. The possible error in the implementation of the cluster state is negligible when the time difference between two atoms crossing the cavity axis is small. It is suggested that the scheme can be realized by current technologies.     

SECOND-ORDER OPTIMALITY CONDITIONS FOR OPTIMAL CONTROL PROBLEMS GOVERNED BY 3-DIMENSIONAL NEVIER-STOKES EQUATIONS

This article is concerned with second-order necessary and sufficient optimality conditions for optimal control problems governed by 3-dimensional Navier-Stokes equations. The periodic state constraint is considered.     

Assisted Cloning and Orthogonal Complementing of an Arbitrary Unknown Two-Qubit Entangled State

Based on A.K. Pati＇s original idea [Phys. Rev. A 61 （2000） 022308] on single-qubit-state-assisted clone, very recently Zhan has proposed two assisted quantum cloning protocols of a special class of unknown two-qubit entangled states [Phys. Lett. A 336 （2005） 317]. In this paper we further generalize Zhan＇s protocols such that an arbitrary unknown two-qubit entangled state can be treated.