光子位相算符的若干性质

本文导出了位相算符e~(iφ)和e~(-iφ)的若干性质,其中包括用围道积分型的广义函数研究e~(-1φ)的本征态和应用及其与e~(iφ)的本征态的关系;讨论了位相算符和谐振子消灭、产生算符的单侧逆算符之间的关系。     

关于光子场相位算符的厄密性

本文讨论了光量子场相位算符φ的厄密性问题。本文用算符对易关系证明了传统的引进厄米算符φ的方法会导致自相矛盾。文中说明了与“亚厄密”算符对应的子空间是不存在的,因此定义φ为“亚厄密”算符是不能成立的。本文还讨论了φ算符本征态的定义中存在的问题。     

反常玻色产生算符的本征右矢

鉴于反常玻色系统在相对论协变的零质量的矢量场中的重要地位和作用,利用Dirac函数的围道积分形式及其性质,并借助反常玻色系统粒子数表象的完备性特点,重点推导出了反常玻色产生算符的本征右矢具体的广义解形式,并在此基础上,寻找到与之对应的两组由非共轭反常玻色量子态矢构成的正交完备性关系,进一步发现此正交完备性关系并不与反常玻色系统中常出现的度规算符相关.最后,作为上述结论的应用,还推导出了量子力学和量子光学中经常出现的两个多项式（即:Hermite多项式和Laguerre多项式）的围道积分下的表示式,该表示形式具有普适性,可能对于解决有关以上两个多项式的量子光学问题提供帮助.     

两类压缩态光场的特性比较

本文指出光场压缩态|α,z〉A=S(z)D(α)|0〉和|α,z〉B=D(α)S(z)|0〉不完全等价,它们实质上是本文命名的压缩子(Squeezon)湮灭算符b=SaS~+的两个本征态,具有完全相同的压缩特性,但本征值不同,光子统计分布和光子统计特性有显著差异,所含的能量状况亦很不相同。     

单一双模组合压缩态的相位性质

本文用正规乘积内的积分技术计算了位相算符的单一双模组合压缩态期望值,作为其特殊情况,分析了双模压缩态的相应性质。     

量子光学中新的广义P-表示

本文利用谐振子产生算符的围道积分δ函数形式的本征态和Glanber相干态所构造的双重围道积分型完备性条件,建立了新的广义P-表示,其特点是当密度矩阵为正规乘积时,这种表示极易导出,而且即使当Glauber P-表示是奇异函数,新的广义P-表示仍为好函数。     

光子场相位算符的若干问题

本文详细地论证了作为可观测量,但并不具有完备厄米性的光子场相位算符(φ、cosφ与sinφ)是能够和量子力学基本原理相容的。此项工作希望能有助于澄清与此相关的一些理沦上的混乱与矛盾。为此,也有必要在厄米性问题上给相位算符“正名”,建议称φ、cosφ与sinφ为“亚厄米算符”;exp(±iφ)—“亚么正算符”。同时还讨论了其他有关问题,例如如何将相位算符引入量子论,等等。     

外场驱动下扩散过程中密度矩阵主方程的求解和应用

利用热纠缠态表象方法和有序算符积分技术,求 解了单模腔在振荡外场驱动下扩散过程中的 密度矩阵主方程。基于实模算符和虚模算符作用在热纠缠态上的等效关系,将密度矩阵主方 程转化为态矢 演化方程,给出了其形式解。进一步,导出了密度矩阵用Kraus算符无限和表示的解析解。 证明了Klaus 算符满足归一化条件。作为解的应用,计算了相干态和真空态在该模型中密度矩阵的演化。 计算结果表明:相干态和真空态在振荡外场驱动下扩散过程中都将演化为热场。     

液晶光波导中本征模内场分量间的关系

液晶光波导的本征模场分析是其器件设计的基础与理论支撑,模场分析的准确度直接影响到液晶光波导器件性能的好坏.为了准确分析液晶光波导中本征模场分量间的关系,我们执行了以下步骤.首先,根据麦克斯韦方程组推导出向列相液晶的磁场耦合方程,然后得出非寻常光波本征模式的磁场分量间比值与指向矢旋转角间的定量关系,并利用OptiBPM1...     

湮没算符k次幂本征态的Wigner函数及其非经典特性

利用Fock态表象下的Wigner函数表达式，重构了湮没算符k次幂本征态的Wigner函数，并依据Wigner函数在相空间的分布规律，讨论了湮没算符k次幂本征态的非经典特性．数值结果表明：湮没算符k次幂本征态的Wigner函数的分布与复参数α的取值有关；湮没算符1次幂的本征态(即相干态)为准经典态(其Wigner函数值总是非负的)，而湮没算符大于或等于2次幂的本征态则都具有明显的非经典特性(它们的Wigner函数均出现了负值).     

基于视觉皮层机制的轮廓整合的神经网络模型

本文以生物视觉功能及其机理有关的研究成果为主要依据,通过分析、建模和模拟计算等方式建立进化的图像目标轮廓组织整合的理论、方法和模型。首先通过分析初级视觉通道内（LGN—〉视觉皮层V1区—〉视觉皮层V2区神经元）目标轮廓的组织整合机理,建立具有广泛视觉心理学和生理学基础人工神经网络模型;然后将该模型应用于自然场景图像的目标轮廓组织及整合的模拟计算中,并根据实验结果对模型做出分析与评估。     

双模真空压缩态在相阻尼情况下的量子纠缠与非定域性

研究了双模真空压缩态在相阻尼情况下的非定域动力学和纠缠特性.在得出该系统密度演化算符的明晰表达式后,我们基于"宇旋算符"而引入合适的Bell算符,从而很好的揭示了该态的非定域性.通过计算其相对熵纠缠度,我们也很好的揭示出其纠缠特性.     

介观LC回路数-相量子化和Josephson结的Cooper对数-相量子化

传统的介观LC回路的量子化是将电量q和电感与电流的乘积L×I分别作为量子力学中的坐标算符Q和动量算符P来处理;本文采取另外一种量子化的观点,即将电量q(q=en)中的n作为荷数算符,并建立电流和相算符θ之间对应关系,就能实现介观LC回路的数-相范畴的量子化,并得到以数-相算符表示的Hamiltonian;通过引进纠缠态表象,对超导Josephson结也可以实现Cooper对数-相量子化,并给出了相应的物理解释.     

彩色空间的视频对象自动分割

提出了一种基于RGB空间的视频对象自动分割方法。图像简化阶段，采用连接算子中的区域开启闭合算子来简化图像；图像标识提取阶段利用RGB空间的信息得到准确的视频对象轮廓，根据对比度消除区域中噪声小梯度，并在此基础上提取标识，在分水岭阶段，采用类似区域增长的改进分水岭方法，实验证明此方法的结果准确可靠。     

A class of 1-generator quasi-cyclic codes

If R = F/sub q/[x/spl rceil/]/(x/sup m/ - 1), S = F/sub qn/[x]/(x/sup m/ - 1), we define the mapping a_(x) /spl rarr/ A(x) =/spl sigma//sub 0//sup n-1/a/sub i/(x)/spl alpha//sub i/ from R/sup n/ onto S, where (/spl alpha//sub 0/, /spl alpha//sub i/,..., /spl alpha//sub n-1/) is a basis for F/sub qn/ over F/sub q/. This carries the q-ray 1-generator quasicyclic (QC) code R a_(x) onto the code RA(x) in S whose parity-check polynomial (p.c.p.) is defined as the monic polynomial h(x) over F/sub q/ of least degree such that h(x)A(x) = 0. In the special case, where gcd(q, m) = 1 and where the prime factorizations of x/sub m/ 1 over F/sub q/ and F/sub qn/ are the same we show that there exists a one-to-one correspondence between the q-ary 1-generator quasis-cyclic codes with p.c.p. h(x) and the elements of the factor group J* /I* where J is the ideal in S with p.c.p. h(x) and I the corresponding quantity in R. We then describe an algorithm for generating the elements of J*/I*. Next, we show that if we choose a normal basis for F/sub qn/ over F/sub q/, then we can modify the aforementioned algorithm to eliminate a certain number of equivalent codes, thereby rending the algorithm more attractive from a computational point of view. Finally in Section IV, we show how to modify the above algorithm in order to generate all the binary self-dual 1-generator QC codes.     

与双模SU（2）相干场相互作用的∧型三能级原子系统中光场位相特性和原子的相干捕获

本文研究了与双模SU(2)相干场相互作用的∧型三能级原子系统中光场位相的动态特性,证明了光场每个模的位相及两个模的位相和均保持随机分布,给出了光场两个模位相差的平均值及方差表达式,探讨了系统 初态及原子－光场耦合强度对光场两个模位相差涨落的影响,并揭示了在适当的条件下,系统呈现原子的相干捕获现象。     

与双模SU(2)相干场相互作用的Λ型三能级原子系统中光场的位相特性和原子的相干捕获

本文研究了与双模ＳＵ（２）相干场相互作用的Λ型三能级原子系统中光场位相的动态特性，证明了光场每个模的位相及两个模的位相和均保持随机分布，给出了光场两个模位相差的平均值及方差表达式，探讨了系统初态及原子－光场耦合强度对光场两个模位相差涨落的影响，并揭示了在适当的条件下，系统呈现原子的相干捕获现象．     

Threshold training of two-mode signal detection

In certain systems of signal detection and pattern recognition, the process of training an observer to distinguish levels of sensory excitation or to recognize patterns, involves an adaptive threshold adjustment. These "threshold learning processes" (TLPs) can be modeled by finite-state Markov chains. When the output statistics of these TLPs move at random between two sets of parameters, we have a "two-mode" TLP. A probabilistic measure of the training and working performance of two-mode TLPs is proposed. A method of designing periodic train-work schedules for two-mode TLPs is described. For many two-mode TLPs the ratio of working time to retraining time yielding a desired performance level is maximized when the work-retrain period is made as small as possible. The final success probability in a working phase of any two-mode Markov chain cannot be less than one-half of the success probability at the beginning of that working phase. Train-work schedules can exploit the adaptive properties of trainable detectors to overcome not only the unpredictability of the mode, but also the designer's ignorance of the channel statistics.     

基于双谱理论的雷达辐射源指纹特征提取

针对雷达辐射源指纹特征提取困难的问题,提出了基于双谱切片法和双谱围线积分法,提取辐射源指纹特征的方法。介绍了二相编码信号的无意调制,仿真了理想情况和含有相位噪声的二相编码信号的时域波形。阐述了含相位噪声雷达信号的双谱估计,仿真了含相位噪声的二相编码信号的双谱图及等高图。最后利用双谱切片法和双谱围线积分法,提取了辐射源的指纹特征,通过计算机仿真实验验证了该方法的可实施性。     

Contour detection based on nonclassical receptive field inhibition

We propose a biologically motivated method, called nonclassical receptive field (non-CRF) inhibition (more generally, surround inhibition or suppression), to improve contour detection in machine vision. Non-CRF inhibition is exhibited by 80% of the orientation-selective neurons in the primary visual cortex of monkeys and has been shown to influence human visual perception as well. Essentially, the response of an edge detector at a certain point is suppressed by the responses of the operator in the region outside the supported area. We combine classical edge detection with isotropic and anisotropic inhibition, both of which have counterparts in biology. We also use a biologically motivated method (the Gabor energy operator) for edge detection. The resulting operator responds strongly to isolated lines, edges, and contours, but exhibits weak or no response to edges that are part of texture. We use natural images with associated ground truth contour maps to assess the performance of the proposed operator for detecting contours while suppressing texture edges. Our method enhances contour detection in cluttered visual scenes more effectively than classical edge detectors used in machine vision (Canny edge detector). Therefore, the proposed operator is more useful for contour-based object recognition tasks, such as shape comparison, than traditional edge detectors, which do not distinguish between contour and texture edges. Traditional edge detection algorithms can, however, also be extended with surround suppression. This study contributes also to the understanding of inhibitory mechanisms in biology.