氮分子第一正带系振子强度的理论计算

将前文提出的选择组态函数的准则从双电子激发扩充到三电子激发;采用投影算符消除其它多重态的影响;根据组态互作用法计算了氮分子第一正带系的振子强度,其值为0.00198,与实验完全吻合。     

自旋为任意整数的传播子

以自旋为任意整数的自由粒子的波函数(Bargmann-Wigner方程的解)为基础，进一步研究了 自旋为任意整数的投影算符和传播子.证明了Behrends和Fronsdal所构造的投影算符是正确 的.导出了自旋为任意整数的场的一般对易规则和费恩曼传播子的一般表达式. 关键词： 整数自旋 投影算符 对易规则 费恩曼传播子     

坐标算符本征矢的表示与不对称投影算符的积分

借助于粒子数算符的本征态和坐标算符函数的本征方程,把坐标算符的本征矢〈f(x)|表示为一个算符对坐标本征矢〈x|的作用.由此,把不对称的坐标投影算符转换为对称的坐标投影算符,再利用坐标本征矢的完备性,给出不对称坐标投影算符的积分. 关键词： 本征矢 算符的积分 本征方程 完备性     

纠缠态投影算符的积分

借助湮没算符的本征值方程及其本征态的完备性,证明了纠缠态的完备性．在此基础上,利用纠缠态所满足的本征值方程,得到了非对称纠缠态投影算符的积分． 关键词： 完备性 纠缠态 投影算符 积分     

双模坐标-动量积分型投影算符及其在量子光学中的应用

引进了幺正的双模坐标-动量积分型投影算符,利用有序算符内的积分（IWOP）技术分析了其变换特性,并导出了其正规乘积展开式.然后利用该积分型投影算符对角化了双模耦合量子谐振子体系的哈密顿量,从而求出了体系的本征能级与本征波函数.最后讨论了特例情形. 关键词： 积分型投影算符 有序算符内的积分技术 坐标-动量耦合     

双模积分型投影算符及其应用

引进了幺正的双模积分型投影算符,利用有序算符内的积分(IWOP)技术分析了其变换特性;然后利用该积分型投影算符对角化了双模耦合量子谐振子体系的哈密顿量,从而求出了体系的本征能级与本征波函数;最后讨论了特例情形.     

氮分子第二正带系振子强度的理论计算

根据组态互作用法,采用TQ-16电子计算机及CROMEMCO微处理机计算了氮分子激发态C~3П_u、B~3П_g的能量及波函数,提出了一套选择组态函数的准则.采用投影算符消除其它多重态的影响.在偶极近似情况下,氮分子第二正带系振子强度的计算值为0.09739,与实验值颇相符合.本文提出的方法可应用于所有双原子分子.     

求坐标表象中压缩算符显式的3种方法

分别用提取变量积分法、正规乘积内的积分技术及投影算符转换法,得到了坐标表象中压缩算符的显式.     

多核子系统波函数的转动群分类

本文给出了对多核子系统波函数进行转动群分类的投影算符方法,并对1p壳A=1—3的具体情况进行了计算。     

耦合系统的主方程(Ⅰ)

本文运用与时间有关的投影算符,推导出广义耦合主方程,并在第一级玻恩近似下,推出 N 个任意子系的只含对角元部分的耦合主方程.     

Projection operator techniques and Hilbert space averaging in the quantum theory of nonequilibrium systems

The development of efficient strategies for the treatment of the dynamics of relevant observables in complex quantum systems plays a decisive role in the theory of quantum relaxation and transport behavior. Here we discuss the most important tools that are based on the projection operator techniques of nonequilibrium statistical mechanics. For both the Nakajima-Zwanzig and the time-convolutionless projection operator technique we derive the equations of motion for a set of relevant observables and develop explicit expressions in second and fourth order of the corresponding perturbation expansions. We also discuss the Hilbert space average method which is based on the idea of a best guess of conditional quantum expectations determined by an average over a suitable region in the underlying Hilbert space, and relate this method to the projection operator technique.     

Non-Equilibrium Projection-Operator for a Quenched Thermostatted System

A projection operator formalism is presented which allows to derive an exact set of equations for correlation functions and susceptibilities in out of equilibrium situations of many particle systems. Explicitely considered is the case of an initial temperature quench in a simple liquid stabilized by a Gaussian thermostat. Implications for the violation of the fluctuation dissipation theorem in simple structural glass formers like Lennard–Jones glasses and colloidal glasses and the differences to the Kawasaki–Gunton projection operator are discussed.     

Quantitative evaluation of nonlinear diffusion for isotropic random flow

The projection operator method is applied to isotropic random flow field. This application derives a model of a time correlation function with no assumption, and allows for quantitative evaluations of the nonlinear diffusion near initial time. We confirm that for wide range of Reynolds number, the model exhibits good agreement with the results calculated by the direct numerical simulation near the initial time. It is concluded that the projection operator method is useful to exhibit quantitatively the dependence of the nonlinear diffusion on the Reynolds number.     

Feynman propagator for an arbitrary half—integral spin

Based on the solution to Bargmann－Wigner equation for a particle with arbitrary half-integral spin, a direct derivation of the projection operator and propagator for a particle with arbitrary half-integral spin is worked out. The projection operator constructed by Behrends and Fronsdal is re-deduced and confirmed and simplified, the general commutation rules and Feynman propagator with additional non-covariant terms for a free particle with arbitrary half-integral spin are derived, and explicit expressions for the propagators for spins 3/2, 5/2 and 7/2 are provided.     

Dynamics of Multi-Level Open Quantum Systems with Initial System-Environment Correlations

Physics of Particles and Nuclei Letters - Exact and approximate master equations were derived by the projection operator method for the reduced statistical operator of a multi-level open quantum...     

Optimally chosen Nakajima–Zwanzig master equation for mean field approximation

We define an ensemble of projection operators, each of which has an exact associated Nakajima–Zwanzig master equation for quantum open system evolution. A mean field approximation for the memory kernels is introduced that yields a completely determined inhomogeneous master equation for every projection operator. A specific projection operator is then chosen so that the master equation optimally matches an abstract mathematical form which preserves positivity, complete positivity, and correctly equilibrates. We study a nitrogen vacancy center in diamond interacting with ¹³C impurities to illustrate the method.