量子化介观RLC并联电路在热真空态下的量子效应

根据热场动力学理论,研究了具有普遍意义的量子化介观RLC并联电路在热真空态下产生的量子效应,并分析在各支路中电流和电压的量子涨落与电路元件、环境热真空态以及时间三个方面因素的关系。结果表明,处于热真空态下的量子化介观RLC并联电路,各支路电流和电压的量子涨落均受到这三个方面因素的影响, 并且具有如下规律, 电流和电压的涨落均随时间按指数规律衰减,但衰减速度仅与电路元件的参数有关,而初始时刻涨落的大小由电路元件参数和环境热真空态的温度共同决定。     

耗散介观RLC串并联电路的量子涨落

借鉴阻尼谐振子正则量子化的方法,实现了对耗散介观RLC串并联电路的量子化,并在此基础上,研究了真空态下电路中电荷和自感磁通链、电压和电流的量子涨落。结果表明,电路中电荷和自感磁通链、电压和电流在真空态下都具有各自的量子涨落,且量子涨落及量子涨落积的大小皆与电路中的器件参数有关,并随时间按指数规律衰减。     

激发相干态下介观电感耦合电路的量子效应

从无耗散介观电感耦合电路的经典运动方程出发,运用线性变换的方法对电路进行量子化,在此基础上计算了激发相干态下电路中电荷、电流的量子涨落。结果表明,在未接电源时各回路电荷、电流的平均值和方均值均不为零,存在量子涨落,涨落大小不仅取决于回路自身的参数,还与另一回路参数以及耦合电感参数有关,即两回路的量子噪声是相互关联的,而且它们还明显地依赖于电路所处的状态参数,即粒子数态参数和相干态参数。     

海森堡对应原理在含时介观耦合电路中的应用

对于一般形式的含时电容和电感耦合电路，利用Heisenberg对应原理研究了体系的量子经典对应关系以及量子涨落。通过海森堡绘景中的波函数和运动方程的精确解，在大量子数极限下由量子解得到了经典解。对矩阵元中初始相位求平均得到了体系中电荷和磁通量的量子涨落。当电路中的电感随时间指数增加，而电容指数减小时，电路中的电荷和电流的量子涨落也随时间指数减小；当两个分回路中的电容和电感不随时间变化且相等时，发现耦合电容趋于减小电流的量子涨落，而耦合电感趋于减小电荷的量子涨落。     

电容电荷守恒和电感磁链守恒的条件

动态电路换路时，若存在由纯电容和理想电压源构成的回路，则电容电压就有可能跃变，在含电压可能跃变的电容支路的割集中，若除电容支路外的支路中无冲激电流存在，则电容电荷守恒，否则电容电荷有可能不守恒；若存在由纯电感和理想电流源构成的割集，则电感电流就有可能跃变，在含电流可能跃变的电感支路的回路中，若除电感支路外的支路中无冲激电压存在，则电感磁链守恒，否则电感磁链有可能不守恒。文中同时给出了电容电荷不守恒和电感磁链不守恒时电路初始条件的求解方法。     

Buck型DC-DC电路振铃现象的抑制

Buck型DC-DC电路在负载较大时,外接电感电流在一个调制周期内会出现减小到零的情况。为了防止电路进入强制连续导通模式(FCCM),电感电流反向,导致负载电容通过续流NMOS管放电,降低DC-DC的转换效率,需要设计保护电路在电感电流减小到零时检测电感前端电压,当电压大于零时强制关断NMOS管,使电路工作于断续导通模式(DCM)。由于开关管寄生电容与外接电感LC形成振荡回路,电感残余电流产生振铃现象。为了抑制振铃现象,通过控制电路在LXC与地之间接入阻尼电阻,减小电容的等效并联电阻,加快振荡衰减。     

有互感的介观电感电容耦合电路的量子效应

利用正则变换和幺正变换的方法研究了有互感的介观电感电容耦合电路的量子效应，并把介观电感电容耦合电路和另外几种耦合电路进行了比较。发现在耦合电容存在的有互感的电路中，通过调节互感耦合系数来控制电路的量子涨落和压缩效应是很方便的。电路中电荷和电流的不确定关系与正则变换参数ψ和不确定关系参数ξ有关。当ξ→1或ψ→nπ／2(n=0，1，2，…)时，电荷和电流的不确定关系接近最小值h／2。     

电路分析（一）

电子线路是由电和（或）磁的积木块连接而构成。每块有两个或两个以上电气接线,它们的连接点称为网络的节点。网络中的电压就是这些节点的电压（位）之间的差。流出节点的电流即支路电流,流过电路的元件,从而在节点之间产生电压差。本文的目的是介绍由实际的元件构成的网络的分析方法和过程。这些元件是大家熟悉的二端元件（电阻、电容、电感、二极管、电压源和电流源）、三端元件（三极管）和多端元件（变压器）。     

光电子技术与激光基础

0005557介观电感耦合电路的量子涨落[刊]/嵇英华//量子电子学报.—1999,16(6).—526～531(E)提出了电感耦合电路的一种量子化方案,研究了电路中电荷和电流在相干态下的量子涨落,结果表明两个回路中的量子涨落是相互关联的,并对结果进行了讨论。参2     

有限温度下生物细胞中电流电压的量子涨落

在介观生物细胞等效电路量子化的基础上通过热正则Bogoliuov变换，研究了有限温度下介观生物细胞中电流和电压的量子涨落。结果表明，介观生物细胞中电流电压的量子涨落不仅与其等效电路的参数有关，还与温度有关，且随时间衰减。     

Master equation and conversion of environmental heat into coherent electromagnetic energy

We derive a non-Markovian master equation for the long-time dynamics of a system of Fermions interacting with a coherent electromagnetic field, in an environment of other Fermions, Bosons, and free electromagnetic field. This equation is applied to a superradiant p–i–n semiconductor heterostructure with quantum dots in a Fabry–Perot cavity, we recently proposed for converting environmental heat into coherent electromagnetic energy. While a current is injected in the device, a superradiant field is generated by quantum transitions in quantum dots, through the very thin i-layers. Dissipation is described by correlated transitions of the system and environment particles, transitions of the system particles induced by the thermal fluctuations of the self-consistent field of the environment particles, and non-local in time effects of these fluctuations. We show that, for a finite spectrum of states and a sufficiently weak dissipative coupling, this equation preserves the positivity of the density matrix during the whole evolution of the system. The preservation of the positivity is also guaranteed in the rotating-wave approximation. For a rather short fluctuation time on the scale of the system dynamics, these fluctuations tend to wash out the non-Markovian integral in a long-time evolution, this integral remaining significant only during a rather short memory time. We derive explicit expressions of the superradiant power for two possible configurations of the superradiant device: (1) a longitudinal device, with the superradiant mode propagating in the direction of the injected current, i.e. perpendicularly to the semiconductor structure, and (2) a transversal device, with the superradiant mode propagating perpendicularly to the injected current, i.e. in the plane of the semiconductor structure. The active electrons, tunneling through the i-zone between the two quantum dot arrays, are coupled to a coherent superradiant mode, and to a dissipative environment including four components, namely: (1) the quasi-free electrons of the conduction n-region, (2) the quasi-free holes of the conduction p-region, (3) the vibrations of the crystal lattice, and (4) the free electromagnetic field. To diminish the coupling of the active electrons to the quasi-free conduction electrons and holes, the quantum dot arrays are separated from the two n and p conduction regions by potential barriers, which bound the two-well potential corresponding to these arrays. We obtain analytical expressions of the dissipation coefficients, which include simple dependences on the parameters of the semiconductor device, and are transparent to physical interpretations. We describe the dynamics of the system by non-Markovian optical equations with additional terms for the current injection, the radiation of the field, and the dissipative processes. We study the dependence of the dissipative coefficients on the physical parameters of the system, and the operation performances as functions of these parameters. We show that the decay rate of the superradiant electrons due to the coupling to the conduction electrons and holes is lower than the decay rate due to the coupling to the crystal vibrations, while the decay due to the coupling to the free electromagnetic field is quite negligible. According to the non-Markovian term arising in the optical equations, the system dynamics is significantly influenced by the thermal fluctuations of the self-consistent field of the quasi-free electrons and holes in the conduction regions n and p, respectively. We study the dependence of the superradiant power on the injected current, and the effects of the non-Markovian fluctuations. In comparison with a longitudinal device, a transversal device has a lower increase of the superradiant power with the injected current, but also a lower threshold current and a lesser sensitivity to thermal fluctuations.     

介观无损耗传输线的量子涨落与温度的关系

在无损耗传输线量子化的基础上，用热场动力学理论研究了热Fock态下传输线中电流及单位长度传输线电感上电压的量子涨落，分析了量子涨落与温度的关系．结果表明，在热Fock态下，传输线中的量子涨落不仅与传输线的分布参量、信号的角频率和传输线中的光子数有关，还随着温度的升高而单调地加大．     

介观电感耦合电路的量子涨落

提出了电感耦合电路的一种量子化方案,研究了电路中电荷和电流在相干态下的量子涨落,结果表明两个回路中的量子涨落是相互关联的,并对结果进行了讨论。     

介观金属双环系统中的量子效应

基于电荷离散化的事实,运用最小平移算符的性质,计算介观金属双环系统中电荷、电流以及能量的量子涨落,研究影响量子涨落的因素.结果表明:量子电流、量子能谱的量子涨落不仅与介观金属环的电参量、Plank常数有关,而且还明显地依赖于电荷的量子化性质.     

Quantum fluctuations of mesoscopic damped mutual capacitance coupled double resonance RLC circuit in thermal excitation state

With the rapid development of microelectronics and na- nometer techniques, the trend of the miniaturization of cir- cuits and devices becomes stronger and stronger. The quan- tum effects of mesoscopic system have become one hotspot in condensed matter phy…