测量相位算符在压缩热场态中的压缩效应

利用Bannett和Pegg提出的测量相位算符讨论了压缩热场态中测量相位算符的压缩效应。结果表明测量相位算符在压缩热场态中存在CS类压缩，压缩特性与相干态参数幅角θ、平均光子数n^-和压缩参量r有密切的关系。随着n^-和r的增大，CS类压缩效应逐渐减弱，直至完全消失。另有计算表明测量相位算符在压缩热场态中不存在CN和SN类压缩。     

一种新的三模压缩真空态的量子特性

将三模压缩算符作用在三模真空态上构建三模压缩真空态。对三模中的两个模进行测量,讨论这种选择性测量对第三模的压缩效应、反聚束效应和光子统计分布的影响。研究结果表明:若测得第一和第二模场处于双模压缩态,那么第三个模场塌缩为单模压缩态,且其压缩效应得到增强;量子态测量可增强光子统计分布的非经典特性,但对第三模场的反聚束效应没有影响。     

热噪声的相干态和压缩态中的高阶涨落

利用热场动力学的方法研究了具有热噪声的相干态和压缩态中场正交分量的高阶涨落和高阶压缩.利用测量相位算符讨论了这些热化态中相位的高阶涨落.从而得到在有限温度下这些态的低阶及高阶涨落与温度的关系和压缩特性与温度的关系.由于实际的场态总是在一有限的温度下，所以讨论温度对涨落和压缩的影响是很有意义的. 关键词：     

薛定谔猫态中测量相位算符的压缩效应

利用Ｂａｒｎｅｔｔ和Ｐｅｇｇ提出的测量相位算符讨论了薛定谔猫态中测量相位算符的压缩效应。结果表明,压缩特性与叠加参数有关系,并且随着叠加参数的增加其压缩效应逐步减弱。     

光场算符n次幂叠加激发混沌场的量子特性

构造了光场算符n次幂叠加激发混沌场,采用数值计算方法研究了该量子态的压缩效应、反聚束效应和统计性质,讨论了混沌场平均光子数、算符叠加系数及其幂次n对量子特性的影响.研究结果表明:光场算符n次幂叠加激发混沌场不呈现压缩效应,但呈现出反聚束效应和亚泊松分布性质,并且随平均光子数增大,它的反聚束效应和亚泊松分布性质减弱;随着算符组合部分中产生算符的比重增大,光场反聚束效应和亚泊松分布性质增强;随着算符幂次增大,亚泊松分布性质加强.     

具有有限温度的热克尔态

利用热场动力学方法，提出了具有有限温度的热克尔态，研究了这些态的量子统计性质及其与温度的关系，讨论了这些态中场振幅的涨落与压缩性质．对于热化的场，还提出了热压缩的定义，并对热克尔态，讨论了温度对热压缩的影响     

三参数双模压缩粒子数态的量子特性

利用有序算符内的积分技术,给出了三参数双模压缩算符,构建了三参数双模压缩粒子数态,并且研究了该量子态的压缩效应、反聚束效应和对Cauchy-Schwartze不等式的违背.给出了量子态产生压缩效应和反聚束效应的条件,以及三参数双模压缩粒子数态的Wigner函数的解析式.讨论了参数变化和光子数变化对压缩效应、反聚束效应和Cauchy-Schwartze不等式的违背的影响.研究结果表明:随光子数的增大,压缩效应、反聚束效应和光场两模间的非经典相关性减弱;另一方面,随参数模的增大,压缩效应增强,但反聚束效应和光场两模间的非经典相关性却减弱.     

减光子压缩真空态的反群聚效应

利用玻色产生算符的逆算符及玻色湮没算符作用于压缩真空态来构造减光子压缩真空态,并通过计算减光子压缩真空态的二阶关联函数来讨论它们的光子反群聚性质。数值计算结果表明,在两种情况下所得到的减光子压缩真空态当湮没光子数k为奇数时均呈现出群聚效应,而当k为偶数时呈现反群聚效应。所呈现的反群聚效应对应的压缩参量η的取值区间与湮没的光子数k有关,在玻色产生箅符的逆算符的作用下随着k的增加,反群聚效应对应的压缩参量η的取值区间扩大,在玻色湮没算符作用下则相反。同时,作出二阶关联函数随压缩参量η变化的曲线来描述减光子压缩真空态所呈现的反群聚效应的变化特性。     

一种新的偶奇非线性相干态中测量相位算符的压缩效应

利用Bamett和pegg提出的测量相位算符讨论了一种新的偶奇非线性相干态的压缩效应。结果表明，在这种偶奇非线性相干态中测量相位算符不存在CN和SN类压缩，只存在CS类压缩。利用数值计算方法研究了CS类压缩效应，结果表明与通常的偶奇相干态的不同的是，偶非线性相干态在大区域内出现压缩效应而奇非线性相干态在小区域内才出现压缩效应。     

电磁场与等离子体互作用和广义压缩相干态

本文用量子力学方法研究在一腔中的等离子体与电磁场的相互作用,求得系统的哈密顿量的本征值和本征态,这本征态是一种广义压缩相干态。还求得在广义压缩相干态,场的压缩、反聚束、亚泊松统计等效应以及测量相算符的有关公式,这些效应均为时间守恒的。 关键词：     

Thermo Vacuum State for Describing the Density Operator of Photon-subtracted Squeezed Chaotic Light

For the density operator describing s?photon-subtracted squeezed chaotic light (PSSCL) we search for its thermo vacuum state (a pure state) in the real-fictitious space. We find that it reduces to a thermo vacuum state of squeezed chaotic light when s = 0, and to a thermo vacuum state of the optical negative binomial field when no squeezing. The new thermo vacuum state simplifies calculating photon number average, quantum fluctuation and Mandel’s Q parameter of PSSCL. Using the method of integration within ordered product (IWOP) of operators we also derive the normalization coefficient and explicitly analytical expressions of Wigner function for PSSCL.     

Operator Fredholm Integration Equation in Intermediate Coordinate-Momentum Representation and Its Analogue to Thermo Conduction Equation

Using the technique of integration within an ordered product （IWOP） of operators we construct intermediate coordinate-momentum representation, with which we build a type of operator Fredholm integration equation that is an operator generalization of the solution of thermo conduction equation. Then we seach for the solution of operator Fredholm integration equations, which provides us with a new approach for deriving some operator identities.     

Wigner function of the thermo number states

Based on thermo field dynamics (TFD) and using the thermo Wigner operator in the thermo entangled state representation we derive the Wigner function of number states at finite temperature (named thermo number states). The figure of Wigner function shows that its shape gets smoothed as the temperature rises, implying that the quantum noise becomes larger.     

Quantum fluctuation in excited states of mesoscopic LC circuits at finite temperature

We discuss quantum fluctuation in excited states(named thermo number states) of mesoscopic LC circuits at a finite temperature.By introducing the coherent thermo state into the thermo field dynamics pioneered by Umezawa and using the natural representation of thermo squeezing operator we can concisely derive the fluctuation.The result shows that the noise becomes larger when either temperature or the excitation number increases.     

Quantum Retrodiction in Non-Equilibrium Thermo Field Dynamics

The quantum retrodiction for open systems which obey the quantum Markovian dynamics is investigated by means of non-equilibrium thermo Field dynamics (NETFD) which can easily derive the retrodictive time-evolution generators. NETFD can formulate the quantum retrodiction for open systems in the same way as that for closed systems.     

Infinitive Operator-Sum Representation for Damping in a Squeezed Heat Reservoir via the Thermo Entangled State Approach

Using the thermo entangled state approach, we successfully solve the master equation of a damped harmonic oscillator affected by a linear resonance force in a squeezed heat reservoir, and obtain the analytical evolution formula for the density operator in the infinitive Kraus operator-sum representation. Interestingly, the Kraus operators M_l,m,n,r and \(\mathfrak {M}_{l,m,n,r}^{\dag }\) are not Hermite conjugate, but they are still trace-preserving quantum operations because of the normalization condition. We also investigate the evolution for an initial coherent state for damping in a squeezed heat reservoir, which shows that the initial coherent state decays to a complex mixed state as a result of damping and thermal noise.     

Expectation Value Theorem for Thermo Vacuum States of Optical Chaotic Field and Negative-Binomial Field

For the density operator (mixed state) describing chaotic light and negative-binomial field there exist the corresponding thermal vacuum state (pure state) in the real-fictitious space. Using the method of integration within ordered product of operators we find the expectation value theorem in these two thermo vacuum states respectively. The thermal average theorem of translation operator is also deduced. Application of the new thermo vacuum state in calculating photon number disturibution and fluctuation and thermal average is presented.     

用热场动力学理论研究介观电路的Wigner函数

利用热场动力学及相干热态表象理论,重构了有限温度下介观RLC电路的Wigner函数,研究了有限温度下介观RLC电路的量子涨落.借助于Weyl-Wigner理论讨论了有限温度下介观RLC电路Wigner函数的边缘分布,并进一步阐明了Wigner函数边缘分布统计平均的物理意义.结果表明: 有限温度下介观RLC电路中电荷和电流的量子涨落随着温度和电阻值的增加而增加,回路中的电荷和电流之间存在着压缩效应,这种量子效应是由于系统零点振动的涨落而引起的; 有限温度下介观RLC电路Wigner函数边缘分布的统计平均正好是储存在介观RLC电路中电容和电感上的能量.     

用热场动力学理论研究介观电路的Wigner函数

利用热场动力学及相干热态表象理论,重构了有限温度下介观RLC电路的Wigner函数,研究了有限温度下介观RLC电路的量子涨落.借助于Weyl-Wigner理论讨论了有限温度下介观RLC电路Wigner函数的边缘分布,并进一步阐明了Wigner函数边缘分布统计平均的物理意义.结果表明:有限温度下介观RLC电路中电荷和电流的量子涨落随着温度和电阻值的增加而增加,回路中的电荷和电流之间存在着压缩效应,这种量子效应是由于系统零点振动的涨落而引起的;有限温度下介观RLC电路Wigner函数边缘分布的统计平均正好是储存在介观RLC电路中电容和电感上的能量.     

The Generalized Thermo Jaynes–Cummings Model and?Its Energy Spectrum

By analyzing the characteristics of thermo field dynamics, we present a new generalized thermo Jaynes-Cummings (TJC) model at finite temperature including the thermal effects and expatiate on its physical explanation. By virtue of Lewis-Riesenfeld invariant method, we obtain its exact eigenenergy spectrum and the explicit expressions for the evolution operator of the wavefunctions. In addition, we evaluate various expectation values of physical quantities and find the pseudo-invariant eigen-operator for the generalized TJC Hamiltonian.