共查询到20条相似文献,搜索用时 15 毫秒
1.
研究了非线性系统中非对角情况的Berry相位, 给出了非线性非对角Berry相位的计算公式. 结果表明, 在非线性非对角情况下, 总相位包含有动力学相位, 通常意义的Berry相位, 以及非线性引起的附加相位. 此外, 还包含有非对角情况时所特有的新的附加项. 这新的一项表示, 当系统哈密顿慢变时产生的Bogoliubov涨落, 与另一个瞬时本征态之间的交叉效应, 进而对总的Berry相位产生影响. 作为应用, 对二能级玻色爱因斯坦凝聚体系, 具体计算了非线性非对角的Berry相位.
关键词:
Berry 相位
非对角
绝热演化
玻色爱因斯坦凝聚 相似文献
2.
3.
文章研究了自旋为1的粒子在旋转磁场中的几何相位和动力学相位.推导出如何计算自旋为1的粒子在绝热和非绝热演化中的几何相位和动力学相位公式,并利用这些公式计算其相位.最后我们讨论了三种情况下的Berry相位,当考虑ω1<<ω时,系统处于绝热近似,此时,几何相位就是Berry相位. 相似文献
4.
Kerr效应对非简并双光子J—C模型中光场相位的影响 总被引:4,自引:1,他引:3
应用Pegg-Barnett相位理论研究了高Q Kerr介质腔中的二能级原子与双模光场相互作用系统中光场相位的演化特性,通过计算光场的相位几率分布函数,频率漂移量以相位涨落,分析讨论了Kerr效应对光场相位性质的影响。 相似文献
5.
6.
分析了菲涅耳非相干相关全息(Fresnel incoherent correlation holography,FINCH)系统中纯相位空间光调制器(spatial light modulator,SLM)加载螺旋相位掩模时的点扩散函数.以氙灯为照明光源搭建了FINCH系统,电荷耦合器记录的点源全息图与点扩散函数模拟结果一致.采用该系统分别在SLM上加载双透镜掩模和螺旋相位调制双透镜掩模两种情况下对分辨率板和非染色洋葱细胞成像,给出了成像对比结果.结果表明:采用螺旋相位调制的FINCH系统可以在几乎不牺牲分辨率的情况下提高图像的边缘对比度;同样,对相位物体也可以实现图像的边缘提取和识别.该方法在实时监测活细胞的分裂、形变等方面具有重要应用前景. 相似文献
7.
8.
量子体系演化的几何相位 总被引:4,自引:0,他引:4
量子体系在演化过程中,其状态的时间演化因子除众所周知的由系统能谱决定的动力学相位因子外,还会出现与系统演化路径有关的几何相位因子即Berry相位因子。几何相位的存在已为大量实验所证实,在理论上,已确定了其数学基础是纤维丛理论,并发现它与规范场有某些联系。本文评述了有关几何相位研究工作的进展。 相似文献
9.
介观系统的量子力学及统计物理特征 总被引:1,自引:0,他引:1
介观体系是指介于宏观与微观之间的一类体系。介观体系的线度L满足aL≤Lφ的条件,其中a为原子半径,Lφ是介观体系的载流子保持相位记忆的特征长度,被称为退相位长度,因此介观体系中的载流子始终是相位关联的。退相位长度Lφ由体系的温度和物性共同决定,例如在液氦温度下,正常金属的Lφ可以达到μm量级,因此低温下介观系统的线度几乎是宏观的。介观系统的可观测的物理量仍然定义为大量微观粒子物理量的统计平均,与宏观系统的定义无异,微观粒子的运动遵循量子力学规律。对介观系统的研究始于20世纪80年代,现已成为凝聚态物理中一个令人瞩目的领域。 相似文献
10.
栅线投影三维测量中通过标定技术把二维的相位信息转化为高度信息,提出了一种基于双参考平面的等相位坐标标定方法。该方法利用被测物体上相位和两个参考平面上相位相同的位置坐标,通过线性插值得到物体表面的高度,而不是传统方法中将物体上的相位直接减去参考平面上同一坐标下的相位得到绝对相位,再建立高度和绝对相位之间的函数关系(将此类方法称为等坐标相位法)。所提方法能够同时解决相位-高度转换以及由于栅线投影系统的非线性响应导致的非正弦性误差的问题。理论和实验证实了该方法的有效性。结果显示,等相位坐标法得到的主要由条纹的非正弦性引起的均方根(RMS)误差不到等坐标相位法的一半。 相似文献
11.
QIAN Shang-Wu GU Zhi-Yu 《理论物理通讯》2005,44(8)
There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the evolutions of Yang phase under the cyclic condition and the adiabatic condition for the generaltime-dependent harmonic oscillator, thus reveals the intimate relations between these three non-integrable phases. 相似文献
12.
13.
New approach for deriving the exact time evolution of the density operator for a diffusive anharmonic oscillator and its Wigner distribution function 下载免费PDF全文
Using thermal entangled state representation,we solve the master equation of a diffusive anharmonic oscillator(AHO) to obtain the exact time evolution formula for the density operator in the infinitive operator-sum representation.We present a new evolution formula of the Wigner function(WF) for any initial state of the diffusive AHO by converting the WF calculation into an overlap between two pure states in an enlarged Fock space.It is found that this formula is very convenient in investigating the WF’s evolution of any known initial state.As applications,this formula is used to obtain the evolution of the WF for a coherent state and the evolution of the photon-number distribution of diffusive AHOs. 相似文献
14.
New approach for deriving the exact time evolution of density operator for diffusive anharmonic oscillator and its Wigner distribution function 下载免费PDF全文
Using the thermal entangled state representation, we solve the master equation of a diffusive anharmonic oscillator (AHO) to obtain the exact time evolution formula for the density operator in the infinitive operator-sum representation. We present a new evolution formula of the Wigner function (WF) for any initial state of the diffusive AHO by converting the calculation of the WF to an overlap between two pure states in an enlarged Fock space. It is found that this formula brings us much convenience to investigate the WF's evolution of any known initial state. As applications, this formula is used to obtain the evolution of the WF for a coherent state and the evolution of the photon-number distribution of the diffusive AHO. 相似文献
15.
16.
We study the ground state as well as the first three excited states of the anharmonic oscillator with anharmonicity λx4 for a range of λ = (0, 10) with the first-order logarithmic perturbation iteration method (FOLPIM). This leads to convergent results. The initial choice of the wave function seems only to affect the rate of convergence in the case of the ground state but may critically affect the convergence for the excited states. For large values of λ, convergence is best obtained by choosing the asymptotic solution as the initial “unperturbed” wave function. 相似文献
17.
利用Kinani-Daoud方法构造了非谐振子势的Gazeau-Klauder(GK)相干态和Klauder-Perelomov(KP)相干态,表明两种相干态在非线性谐振子势下具有完全不同的形式,并对两种相干态的完备性以及各自构成的Hilbert空间进行了讨论. 对相干态的Mandel Q参数的研究表明:GK相干态服从亚Poisson统计分布,KP相干态服从超Poisson统计分布.
关键词:
非谐振子
Gazeau-Klauder相干态
Klauder-Perelomov相干态 相似文献
18.
Andrey Pereverzev 《Foundations of Physics Letters》2003,16(5):411-428
We argue that it may be possible to consistently explain the quantum measurement by assuming that the wave function is in one-to-one correspondence with objective physical reality and has no probabilistic interpretation. In the context of such approach we consider the model of a harmonic oscillator linearly coupled to a heat bath and treat the oscillator as the system being measured. Three classes of initial pure states for the bath are considered. Exact expressions for the average values and variances of the oscillator coordinate and momentum as functions of time are considered for each class of pure states. It is shown that these quantities exhibit different asymptotic behavior for different classes of initial states of the bath. In particular, if each mode of the bath is initially in a coherent state, then for an arbitrary initial state of the oscillator the variances of the oscillator coordinate and momentum asymptotically approach the same values as for a coherent state of the free oscillator, while the averages of coordinate and momentum show a Brownian-like behavior. We argue that such behavior shows several features of the quantum measurement and supports our interpretation of the wave function. 相似文献
19.
An-Ling Wang Fu-Ping Liu Zhao-Xian Yu 《International Journal of Theoretical Physics》2010,49(3):531-535
By using of the invariant theory, we have studied the geometric phase in a time-dependent system with Laguerre polynomial
state, the dynamical and geometric phases are given, respectively. The Aharonov-Anandan phase is also obtained under the cyclical
evolution. 相似文献
20.
The behavior of an anharmonic quantum oscillator in a harmonic external electric field is examined. The quasienergy is calculated
numerically as a function of the field parameters (intensity and frequency) for highly excited states. It depends in complex
fashion on frequency and field intensity near resonance. Quasi-intersection of levels is observed in a broad range of quantum
numbers. These effects are manifestations of dynamic chaos in highly excited states of an anharmonic oscillator in an external
field.
Omsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 11–18, February, 1998. 相似文献