Quantum Dynamics of Two Capacitively Coupled Superconducting Islands via Josephson Junctions

In this paper, we consider a system consisting of two capacitively coupled superconducting islands viaJosephson junctions. We show that it can be reduced to two coupling harmonic oscillators under certain conditions,and can be solved exactly in terms of a displacing transformation, a beam-splitter-like transformation, and a squeezingtransformation. It is found that the system evolves by a rotated-squeezed-coherent state when the system is initially in acoherent state. Quantum dynamics of the Cooper pairs in the two superconducting islands are investigated. It is shownthat the number of the Cooper pairs in the two islands evolves periodically.     

电荷离散化时相干态下介观金属环中电荷与电流以及能量的量子涨落

基于电荷量子化的事实,运用最小平移算符Q∧的性质等,计算对应的相干态下介观金属环中电荷、电流及能量的量子涨落,研究影响量子涨落的因素.结果表明:计及电荷的离散性,在相干态下介观金属环中电荷、能量的量子涨落不为零,分别与电荷量子、相干态参量等因素有关;此外,能量的量子涨落还决定于金属环的电感、外磁通及其时间变化率的大小.     

电荷不连续时电容耦合介观电路的量子回路方程及其能谱

考虑电荷具有不连续性的事实对双LC介观电路进行量子化,给出耦合形式的量子回路方程以及无相互作用Hamilton本征基矢下的电路能谱.结果表明,计及电荷离散性将使回路方程的形式发生明显变化;介观电路的能谱除与电路参数相关外,还明显地依赖于电荷的量子化性质.     

Quantum Superposition of Two Coherent States in a Mesoscopic Josephson Junction

We study a mesoscopic Josephson junction in a circular superconducting ring which encloses a magneto static flux. It is shown that with the junction being initially prepared in vacuum state, the state of the junction can evolve into a quantum superposition of two coherent states.     

Exact Form Factors for the Josephson Tunneling Current and Relative Particle Number Fluctuations in a Model of Two Coupled Bose–Einstein Condensates

Form factors are derived for a model describing the coherent Josephson tunneling between two coupled Bose–Einstein condensates. This is achieved by studying the exact solution of the model with in the framework of the algebraic Bethe ansatz. In this approach the form factors are expressed through determinant representations which are functions of the roots of the Bethe ansatz equations.     

The Quantization of Mesoscopic Electric Circuit with the Discreteness of Electron Charge

The importance of discreteness of electron charge for mesoscopic electric circuit is addressed. A quantization bf the circuit in accord with the discreteness of electric charges is proposed, and a Schrödinger equation incharge representation'is obtained. The Schrödinger equation is turned to be Mathieu equation in'current representation', the wavefunction and energy spectrum can be solved exactly. The WKB solutions of the energy levels for the ground state and the excited states are given.     

交变电源作用下介观电感耦合电路中电荷与电流的量子涨落

利用量子厄米不变量理论,我们研究了交变电源作用下介观电感耦合电路的量子动力学,不仅得到了含时薛定谔方程的精确解,计算了电路中电荷与电流的量子涨落,同时也得到了介观电路的非绝热非循环几何相位的表达式.     

双光子过程耦合腔系统中光场的量子特性

本文研究了双光子过程原子与耦合腔相互作用系统中腔场的压缩效应和反聚束效应.考虑系统总激发数等于2的情况,利用数值计算方法讨论了腔场间的耦合强度变化和原子与腔场间耦合强度变化对反聚束效应的影响.研究结果表明:腔场不呈现出压缩效应;腔场的反聚束效应与原子与腔场的耦合系数之间,以及与腔场间的耦合系数之间都存在着非线性关系,     

The Quantum Fluctuations of Mesoscopic Damped Mutual Capacitance Coupled Double Resonance RLC Circuit in Excitation State of the Squeezed Vacuum State

Mesoscopic damped double resonance mutual capacitance coupled RLC circuit is quantized by the method of damped harmonic oscillator quantization. The Hamiltonian is diagonalized by unitary transformation. The eigenenergy spectra of this circuit are given. The quantum fluctuations of the charges and current of each loop are researched in excitation state of the squeezed vacuum state, the squeezed vacuum state and in vacuum state. It is show that, the quantum fluctuations of the charges and current are related to not only circuit inherent parameter and coupled magnitude, but also quantum number of excitation, squeezed coefficients, squeezed angle and damped resistance. And, because of damped resistance, the quantum fluctuation decay along with time. PACS numbers: 03.65.-w,42.50.Lc.     

Kerr介质中耦合V型三能级原子与相干态光场作用场的量子性质

研究了Kerr介质中相干态光场与耦合V型三能级原子相互作用过程中场的量子性质.利用量子光学中光场与原子相互作用的耦合Tavis-Cummings模型,对系统的动力学过程进行了求解.讨论了系统初始状态、失谐量、原子间偶极相互作用强度及Kerr系数对光场量子性质随时间演化的影响.数值计算结果表明:初态中场的平均光子数比较小时,光场能够展现出明显的量子效应|初始时刻原子激发态概率幅从小变大时,光场的反聚束效应变得越明显,而光场的压缩深度会先增大后减小|失谐量的变化对场的量子性质的影响不大,只是改变光场二阶相关函数和压缩参量振荡的周期|原子间耦合强度的增大使光场的反聚束效应减弱和光场的压缩深度变浅|Kerr系数的增大会增强光场的反聚束效应,而使光场的压缩深度变浅.     

UV-Visible Spectrophotometric Investigations of Charge Transfer Complexes of Some P-N,N-Dimethylaminobenzylidene Ailines with the New Acceptor PFB and CA Acceptor

The CT complexes of PFB and CA acceptors with eleven benzylidene anilines donors have been investigated spectro-photometrically in the uv-visible region for the first time. The values of Ip of these compounds have been estimated from their complexes with CA, the values are in the range of 8.64–8.96 ev. From these values the constants of the new acceptor PFB a, b, c₁, c₂ and Ea have been calculated, the values are 0.91, -5.31, 7.13, 1.97, and 1.37 ev, respectively. The CT parameters of our donors with PFB and CA acceptors, ζCT, ^KCT ΔG° and W have also been estimated and discussed.