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Weyl-Wigner理论研究有限温度下介观电路的量子特性

利用相于热态表象理论,研究有限温度下RLC电路的Wigner函数及量子涨落.借助于Weyl-Wigner理论讨论了介观RLC电路Wigner函数的边缘分布.结果表明: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.     

有源RLC介观电路量子化过程中幺正算符的选择

采用正则变换和正变换方法对有源RLC介观电路实现了量子化，通过构造几种不同形式的幺正算，对介观电路实施量子化的计算过程的比较分析，得到了构造幺正算符的最佳方案，该方案能够使正则变换与幺正变换的结果完全吻合。     

介观电路的量子效应

本用涨落耗散定理证明了一个有源ＲＬＣ电路，在温度接近绝对零度时，存在量子效应；而当温度升高时，这一量子效应被热力学涨落淹没，并给出了绝对零度时，该电路的量子噪声的大小，以及电荷，电流的测不准点系。     

介观RLC电路的量子效应

将介观电容器看作介观隧道结,对介观RLC电路作了相应的量子力学处理.研究了介观RLC电路系统的量子态演化.研究表明:考虑介观电容耦合效应的影响,介观RLC电路系统将由初始的Fock态演化到压缩Fock态,并讨论了电荷及磁通在压缩Fock态下的量子涨落.     

R(t)LC介观电路的量子力学处理

通过正则化变换技巧,采用费曼路径积分方法,完成了R(t)LC介观电路的量子化工作,并研究了介观电路的电荷和广义电流的量子涨落以及两者的不确定关系. 关键词：     

介观RLC电路在热真空态下的量子涨落

利用热场动力学的方法研究了介观RLC电路在具有热噪声的真空态下电荷和磁通(电流)的量子涨落.从而得到了有限温度下这一电路在热真空态下的量子涨落与温度的关系.结果表明,介观RLC电路的量子涨落不仅与电路中的元件参量和电路的共振频率ω有关,而且与温度T有关.温度越高,介观RLC电路的量子噪声越大 关键词： 介观RLC电路 热真空态 量子涨落     

介观电路压缩态的热动力学研究

利用信息理论和密度矩阵，分析研究了频率随时间变化的介观LC电路中的相干态及压缩态。通过与密度矩阵相关算符，我们将相干态、压缩态的出现与电路的初始条件联系起来。结果显示：系统量子态的演化和初始状态密切相关。一般来说，由于环境温度的影响，初始处于某一激发态的介观LC电路系统会演化到压缩态；在低温下，让电路参数作阶跃变化，如果跃变前后电路的谐振频率不变，则能够制备出压缩最小测不准态。     

脉冲信号对介观RLC电路量子态的影响

研究了外加脉冲信号对介观RLC电路量子态变化的影响.结果表明：当电路参数一定时，通过控制脉冲信号参数的变化可以调节介观电路量子态变化的跃迁概率；而当脉冲信号宽度是某个最小量的整数倍时，系统的量子态保持不变.最小量的值与电路参数有关，但与脉冲信号幅度无关.电阻越大，保持系统量子态稳定的脉冲信号最小宽度则越宽. 关键词： 介观RLC电路 脉冲信号 量子态     

介观串并联RLC电路的量子涨落

借鉴阻尼谐振子的量子力学处理的研究思想,将介观RLC串并联电路量子化．在此基础上,研究了真空态下各支路电流和电压的量子涨落．结果表明,各支路电流电压的量子涨落均与电路器件的参数有关,且随时间衰减．     

Marginal Distribution of Wigner Function in Mesoscopic RLC Circuit at Finite Temperature and Its Application

By means of the Weyl correspondence and Wigner theorem the marginal distribution of Wigner function in mesoscopic RLC circuit at finite temperature was discussed. Here we endow the Wigner function with a new physical meaning, i.e., its marginal distributions’ statistical average for q ²/(2C) and p ²/(2L) are the temperature-related energy stored in capacity and in inductance of the mesoscopic RLC circuit, respectively.     

Marginal Distributions of Wigner Function in a Mesoscopic L-C Circuit at Finite Temperature and Thermal Wigner Operator

Wigner function in phase space has its physical meaning as marginal probability distribution in coordinate space and momentum space respectively, here we endow the Wigner function with a new physical meaning, i.e., its marginal distributions’ statistical average for q ²/(2C) and p ²/(2L) are the energy stored in capacity and in inductance of a mesoscopic L-C circuit at finite temperature, respectively. PACS numbers: 03.65.-w, 73.21.-b     

Number-Phase Quantization Scheme and the Quantum Effects of a Mesoscopic Electric Circuit at Finite Temperature

For L-C circuit, a new quantized scheme has been proposed in the context of number-phase quantization. In this quantization scheme, the number n of the electric charge q(q=en) is quantized as the charge number operator and the phase difference θ across the capacity is quantized as phase operator. Based on the scheme of number-phase quantization and the thermo field dynamics (TFD), the quantum fluctuations of the charge number and phase difference of a mesoscopic L-C circuit in the thermal vacuum state, the thermal coherent state and the thermal squeezed state have been studied. It is shown that these quantum fluctuations of the charge number and phase difference are related to not only the parameters of circuit, the squeezing parameter, but also the temperature in these quantum states. It is proven that the number-phase quantization scheme is very useful to tackle with quantization of some mesoscopic electric circuits and the quantum effects.     

Wigner optics in the metaxial regime

A consistent methodology is developed, using the Wigner matrix associated with the Helmholtz equation, to treat metaxial optical systems. The propagation equation of this matrix is derived and its relationship with the corresponding paraxial propagation equation is clarified.     

介观RLC电路的精确波函数和压缩态

利用一系列幺正变换求出了介观RLC电路的精确波函数和基本不变量,并发现此系统基本不变量的本征态是压缩态,它可用介观RLC电路的精确波函数来构造。     

任意两个相干态的叠加态的相位分布和Wigner函数(英文)

从相位分布和Wigner函数两个方面研究了任意两个相干态|β〉and |mβeiδ〉的叠加态的量子统计性质.结果表明这种叠加态的非经典特性与β2,振幅系数m,相干态间的位相差δ以及叠加系数间的位相差都有关.当参量选择合适,这种叠加态存在着量子效应.计算了两个相干态等几率混合系综的相位分布和Wigner函数,经过与前者比较,结果表明由于相干项的存在,使得叠加态具有很好的量子力学行为.     

任意两个相干态的叠加态的相位分布和Wigner函数

从相位分布和Wigner函数两个方面研究了任意两个相干态|β〉 and |mβeiδ〉的叠加态的量子统计性质.结果表明这种叠加态的非经典特性与β2,振幅系数m,相干态间的位相差δ以及叠加系数间的位相差都有关.当参量选择合适,这种叠加态存在着量子效应.计算了两个相干态等几率混合系综的相位分布和Wigner函数,经过与前者比较,结果表明由于相干项的存在,使得叠加态具有很好的量子力学行为.     

General Wigner Transforms Studied by Virtue of Weyl Ordering of the Wigner Operator

By virtue of the property that Weyl ordering is invariant under similar transformations we show that the Weyl ordered form of the Wigner operator, a Dirac δ-operator function, brings much convenience for derivingmiscellaneous Wigner transforms. The operators which engender various transforms of the Wigner operator, can alsobe easily deduced by virtue of the Weyl ordering technique. The correspondence between the optical Wigner transformsand the squeezing transforms in quantum optics is investigated.     

General Wigner Transforms Studied by Virtue of Weyl Ordering of the Wigner Operator

By virtue of the property that Weyl ordering is invariant under similar transformations we show that the Weyl ordered form of the Wigner operator, a Dirac δ-operator function, brings much convenience for deriving miscellaneous Wigner transforms. The operators which engender various transforms of the Wigner operator, can also be easily deduced by virtue of the Weyl ordering technique. The correspondence between the optical Wigner transforms and the squeezing transforms in quantum optics is investigated.