| 1. | When the density matrix of the whole ensemble consisted of system - meter is reduced to the microscopic physical system , the system trend quantum decoherence in nature
把由系统与仪器组成的系综的密度矩阵约化到被测系统部分，于是自然趋近量子退相干。 |
| 2. | As the representation of the electron spin angular momentum is two - dimensional or three - dimensional , the electron energy is calculated simplier by the theory of density matrix and average value
当电子在磁场中的自旋角动量的表示为二维和三维时，应用密度矩阵原理求解其能量更为简便。 |
| 3. | The modeling problem of the two - level system exposed to open environment is mainly investigated based on the lindblad quantum master equation described in terms of the density matrix
摘要二能级开放量子系统的调控问题对实现量子计算机的量子门等基础问题有着重要的理论意义和应用价值。 |
| 4. | After studying the relation of distributive function and density matrix , the electron energy is calculated in magnetic field according to the distributive function in the thermodynamic statistical physics and the density matrix average value principle in the quantum mechanics , respectively
摘要研究正则系综中的配分函数与密度矩阵的关系，分别采用热力学统计物理中的配分函数和量子力学中的密度矩阵与平均值原理，计算电子在磁场中的能量。 |
| 5. | Making use of the wigner transform of the one - body density matrix , the coherent density fluctuation model ( cdfm ) is introduced into semiclassical distorted wave ( scdw ) model . the new model is applied to the analyses of multistep direct processes of ( p , p ' x ) reactions to continuum
本文利用单体密度矩阵的wigner变换，将相干密度涨落模型( cdfm )引入半经典扭曲波( scdw )模型，并将新的scdw模型应用于分析预平衡反应( p ， p ' x )中散射到连续态的多步直接过程。 |
| 6. | This dissertation proves that formation of entanglement is smaller than mutual information . as a by - product , this dissertation also proves that there does not exist this kind of quantum state whose nearest separable state is the product of its two reduced density matrices except the state whose classical correlation is zero
证明了结构纠缠小于互信息，同时证明了对于任意的量子态(除了经典关联为0的态) ，它的两个约化密度矩阵的直积不可能为它的最近分离态。 |
| 7. | Based on the propagation law of the cross - spectral density function in the space - frequency domain , the properties of polychromatic vector gsm beams through a paraxial optical abcd system are studied . the analytical propagation expressions for the cross - spectral density matrix of vector gsm beams passing through a paraxial optical abcd system are derived , which permits us to study the propagation properties of vector gsm beams , including the propagation - induced polarization changes , effect of the spectrum bandwidth and irradiance distributions in a unique way . there are some applications of the theoretical results
基于空间一频率域中交叉谱密度函数的传输理论，研究了多色矢量gsm光束通过abcd光学系统传输时偏振特性的变化规律，首次推出了矢量高斯一谢尔模刑fgsm )光束通过近轴abcd光学系统交叉谱密度矩阵的传输公式，并对矢量gsm光束传输中偏振的变化、谱宽的影响和强度的分布等进行了统一研究。 |
| 8. | It is just the difficulty that the strongly correlated electron systems can not be studied by analytical methods , a variety of simulative numerical methods come out sequentially . there are a few typical methods such as the exact diagonalization ( ed ) , the qutum monte carlo ( qmc ) , the variation monte carlo ( qmc ) , the renormalization group ( rg ) , and the density matrix renormalization group ( dmrg ) and so on
正是强关联系统遇到了解析研究的困难，各种数值模拟方法才相继出现，最典型的数值方法有：严格对角化( ed ) ，量子蒙特卡洛( qmc )模拟、变分蒙特卡洛模拟( vmc ) 、数值重整化群( rg )以及密度矩阵重整化群( dmrg )等。 |
| 9. | It is found that the fwm field can cause the asymmetry of electromagnetically induce transparency profile . in addition , the effect of different propagating orientations of probe field on the electromagnetically induced transparency is also discussed . in the molecular multi - level system with the perturbed superposition levels , we discuss the electromagnetically induced transparency , spontaneous emission enhancement , double dark resonance and double electromagnetically induced transparency by using the density matrix equation under weisskopf - winger approximation and dressed - state density matrix equation
针对实际的实验条件，考虑了一种影响量子干涉的新的因素-四波混频场，研究了四波混频场对双光子探测的-型能级体系的eit的影响，发现四波混频场能够导致双光子探测的eit线型的不对称，在此基础上，讨论了不同探测场的传播方式对eit的影响，针对分子中实际存在的包含有微扰能级的不同多能级系统，我们分别采用缀饰态绘景下的密度矩阵方程和weisskopf - wigner近似下的密度矩阵方程详细地讨论了电磁感应透明、自发辐射的干涉相消和相长、双暗态共振和双电磁感应透明现象。 |
| 10. | In the second chapter , the nonlinear optical properties are described from both macroscopic and microscopic views , at the same time , giving the definitions of the linear and nonlinear polarizabilities . then , the explicit expressions of the linear and nonlinear polarizabilities are obtained by using quantum mechanical perturbation theory and density matrix formalism , respectively
第二章非线性光学性质，首先分别从宏观和微观两个角度讨论了极化强度和电偶极矩与外加光电场强度之间的关系，同时给出了线性极化率和非线性超极化率的定义，然后分别运用含时微扰理论和密度矩阵理论求解了分子体系的线性极化率和非线性超极化率。 |
