共查询到20条相似文献,搜索用时 93 毫秒
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通过解析求解简单极化激元模型的Pancharatnam相位, 研究了温度、耦合强度、声子与光子频率差、平均光子数等对其演化的影响. 结果表明,Pancharatnam相位随时间振荡,且振荡频率和振荡波形随时间变化,这种变化随着温度升高和耦合强度、声子与光子频率差增加而加大. 系统Pancharatnam相位随时间的演化在平均光子数较小时表现比较有规律,但随着平均光子数的增加,它趋于混沌化.
关键词:
极化激元
Pancharatnam 相位
Mach-Zehnder干涉仪
相干态 相似文献
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质子-中子相互作用玻色子模型(简称IBM-2)具有很好的壳模型微观基础,是描述中重质量偶偶核结构的标准模型之一。对比早期建立在弱耦合U(5)基底的NPBOS算法,本文介绍基于弱耦合SU(3)基底求解IBM-2模型哈密顿量的新算法结构,通过举例典型相互作用项在SU(3)基底下矩阵元说明如何利用SU(3)群代数技术求解IBM-2哈密顿量,并应用该算法求解常Q形式哈密顿量来拟合过渡区核素152, 154Sm低激发实验数据,提供了一个展示SU(3)算法可靠性和利用IBM-2描述过渡区核素的应用实例。 相似文献
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沈洪清 《原子与分子物理学报》1987,(2)
本文根据泡利原理和洪德定则,用SU(4l+2)群的约化群链SU(4l+2)→SU(2)×SU(2l+1)将状态分类的方法,得到了确定原子基态的普遍公式。 相似文献
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变分-累积量展开方法推广到研究SU(3)格点Wilson模型.对序参数元格能量计算到二级展开,四维时模型没有一级相变,与Monte Carlo结果一致.五维时有一级相变发生.方法可用于格点理论中与SU(3)群有关的各种问题的解析研究. 相似文献
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Josephson结开关电流分布的测量方案探讨 总被引:3,自引:1,他引:2
Josephson结的开关电流存在着一定的分布.利用开关电流的分布,我们可以推算出Josephson结的逸出率.进一步结合合适的微波辐照,还可以获得结的诸如能级、拉比振荡等许多相关的量子特性.Josephson结的开关电流分布的获得,对于研究超导量子比特,包括相位量子比特、电荷量子比特、磁通量子比特和涡流量子比特以及他们的组合量子比特都有着重要意义.我们提出了三种测量方案,对这三种方案进行了比较,并初步的对自制的NbN/AlNx/NbN Josephson结的开关电流进行了多次(104次)测量,得到一定温度下的开关电流分布的直方图.针对三种方案各自的优缺点及已有的结果,我们提出了需要进一步改进的措施,对于下一步开展在极低温下(mK)Josephson结的开关电流分布的测量有着重要的意义. 相似文献
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Isao Nishikawa Naofumi Tsukamoto Kazuyuki Aihara 《Physica D: Nonlinear Phenomena》2009,238(14):1197-1202
We investigate chaotic phase synchronization (CPS) in three-coupled chaotic oscillator systems. According to the coupling strength and mismatches in the frequencies of these oscillators, we can observe complete CPS where all three oscillators exhibit CPS, and partial CPS where only two oscillators exhibit CPS. When the coupling strength is weakened, we observe a phenomenon that complete CPS among the three oscillators is suddenly disrupted without going through partial CPS. In this case oscillators exhibit quasi-CPS where two oscillators appear to exhibit CPS transiently, and the combination of the two oscillators changes with time. We call this phenomenon CPS switching D. It is revealed that phase fluctuation plays an important role in CPS switching D. It is also shown that the amplitude with a specific structure strengthens the degree of CPS switching. In the present paper, we characterize this CPS switching and discuss its mechanism. 相似文献
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In this paper we study the qualitative dynamics of piecewise-smooth slow-fast systems (singularly perturbed systems) which are everywhere continuous. We consider phase space topology of systems with one-dimensional slow dynamics and one-dimensional fast dynamics. The slow manifold of the reduced system is formed by a piecewise-continuous curve, and the differentiability is lost across the switching surface. In the full system the slow manifold is no longer continuous, and there is an O(?) discontinuity across the switching manifold, but the discontinuity cannot qualitatively alter system dynamics. Revealed phase space topology is used to unfold qualitative dynamics of planar slow-fast systems with an equilibrium point on the switching surface. In this case the local dynamics corresponds to so-called boundary-equilibrium bifurcations, and four qualitative phase portraits are uncovered. Our results are then used to investigate the dynamics of a box model of a thermohaline circulation, and the presence of a boundary-equilibrium bifurcation of a fold type is shown. 相似文献
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We show that cascaded second-order nonlinear-optical processes can occur in a convenient polarization-gate beam geometry. Our arrangement uses type II phase matching, and both individual second-order processes (upconversion and downconversion) are simultaneously phase matched. This geometry can be applied to efficient ultrafast optical switching. With a beta-barium borate crystal and lightly focused 250-fs, 7.3-microJ pulses, we achieve a switching efficiency of 15% and an on-off ratio of 3 x 10(4) on a pulse-length-limited time scale. 相似文献
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利用两种方法研究了高速光脉冲在具有交叉相位调制的等边三角形排列结构的非线性三芯光纤耦合器中传输和开关特性.首先利用变分原理得到三纤芯中传输转移系数随距离变化的方程,然后利用分裂步长傅里叶方法求得了光脉冲的数值解.变分法和数值模拟的结果表明:当一阶模间色散系数较小时,光脉冲仍能在三芯之间周期性耦合传输,并且表现出良好的开关特性,但是随着一阶模间色散系数的增大,脉冲耦合传输的周期性和陡峭的开关特性都遭到破坏,光脉冲在传输中发生分裂;二阶耦合色散系数和初始啁啾都能使光脉冲传输时的耦合长度变短、光脉冲在三纤芯之间
关键词:
三芯光纤耦合器
模间色散系数
耦合长度
开关阈值功率 相似文献
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Dynamic resistive switching in a three-terminal device based on phase separated manganites 下载免费PDF全文
《中国物理 B》2015,(3)
A three-terminal device based on electronic phase separated manganites is suggested to produce high performance resistive switching. Our Monte Carlo simulations reveal that the conductive filaments can be formed/annihilated by reshaping the ferromagnetic metal phase domains with two cross-oriented switching voltages. Besides, by controlling the high resistance state(HRS) to a stable state that just after the filament is ruptured, the resistive switching remains stable and reversible, while the switching voltage and the switching time can be greatly reduced. 相似文献
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The kinetics of switching of multiaxial ferroelectric crystals with 180° and 90° domains under conditions of normal and layer-by-layer domain growth is studied using the multidimensional theory of first-order phase transitions. The main stages of the process of switching of a multiaxial ferroelectric are considered under the assumption that repolarized cylinder-shaped domains grow three-dimensionally. A closed set of equations describing the kinetics of switching is derived with allowance for a change in repolarization in the course of the phase transition. Equations for the time-dependent switching current are derived. The main characteristics of switching are compared qualitatively with the experimental data on barium titanate. 相似文献
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Zheng Chen 《Optics Communications》2007,279(1):106-111
All-optical polarization switches based on near-resonant excitation have been demonstrated recently, which operate without significant real carriers excited in MQWs so as to avoid carriers accumulation. In this paper, we focus our investigation on the switch adopting InGaAsP MQWs because it could be compatible with the optical communication system. Our theoretical analysis is restricted to χ3 regime (i.e., the lowest-order nonlinear regime) and based on the dynamics-controlled truncation (DCT) scheme which provides a formalism for studying the coherent dynamics in weakly-nonlinear coherent optics of semiconductors. By using the theoretical model based on DCT theory, the switching action was simulated. With this theoretical model, we study the respective contributions of phase space filling and Hartree-Fock mean field as main terms of the optical Stark effect to the switching process, then exhibit the influence of delay time and control intensity for the switching response. 相似文献