Aharonov—Bohm磁通对一维铁磁链中孤子的影响

分析了Ａｈａｒｏｎｏｖ－Ｂｏｈｍ磁通对一维铁磁链中孤子的影响，结果表明Ａｈａｒｏｎｏｖ－Ｂｏｈｍ磁通对孤子的峰值、宽度、静止能量及有效质量均有影响。     

Aharonov—Bohm磁通对序参量守恒的反铁磁链中孤子的影响

以一维序参量守恒的反铁磁链为例，采用双子格模型和相干态表示，分析了Ａｈａｒｏｎｏｖ－Ｂｏｈｍ磁通对一维反铁磁链中的孤子所产生的影响，结果表明Ａｈａｒｏｎｏｖ－Ｂｏｈｍ磁通对孤子的峰值、宽度、静止能量和有效质量均有影响。     

Josephson结中激发孤子的电泳脉冲方法—原理与数值实验

根据反射射理论讨论了电泳脉冲法产生磁通孤子的阈值条件。对甚长结作的数值实验与理论符合很好。对有限结，考虑到边界效应，电流台阶范围等因素，对孤子激发条件有额外的要求。对圆对称环域结用脉冲法激发了孤子，并分析了其中回波效应、外磁场等对激发条件的影响。所有结果表明，电流脉冲法是在Ｊｏｓｅｐｈｓｏｎ结中激发孤子态的有效方法，理论阈值条件可以提供有益的参考作用。     

Josephson结中激发孤子的电流脉冲方法──原理与数值实验

根据反散射理论讨论了电流脉冲法产生磁通孤子的阈值条件。对甚长结作的数值实验与理论符合很好。对有限结，考虑到边界效应，电流台阶范围等因素，对孤子激发条件有额外的要求，对圆对称环域结用脉冲法激发了孤子，并分析了其中回波效应、外磁场等对激发条件的影响。所有结果表明，电流脉冲法是在Ｊｏｓｅｐｈｓｏｎ结中激发孤子态的有效方法，理论阈值条件可以提供有益的参考作用。     

噪声扰动对环形圆对称Josephson结第一零场台阶的影响

本在环形圆对称Ｊｏｓｅｐｈｓｏｎ结Ｓｉｎｅ－Ｇｏｒｄｏｎ方程的基础上，考虑在实际物理环境必然存在热噪声和各种电磁噪声，加入无规随机噪声的影响，对环形结的孤子运动和第一零场台阶进行数据模拟计算，观察磁通孤子在噪声涨落电流作用下的运动情况，发现了不同于理想结的孤子运动模式转变现象，讨论了涨落电流在这些现象中所起的作用，并分析了噪声涨落对环形结各种物理性质的影响。     

通过嵌入铁磁电极之间 Aharonov-Bohm 干涉仪自旋极化输运性质的研究

使用非平衡态格林函数方法和运动方程近似,研究了嵌入铁磁电极之间Aharonov-Bohm 干涉仪的自旋极化输运性质.在左右铁磁电极平行和反平行两种磁组态下,结合Fano因子分析和讨论了Fano 和Kondo 共振对该系统电导的影响,以及电导随自旋极化强度和磁通的变化.结果表明,自旋极化强度和磁通能有效地调节和控制电导,但电导的线形主要由磁通决定;在适当的条件下能导致大的正磁阻和负磁阻的出现.因此,该系统是一个很好的自旋阀晶体管,在自旋电子学中有潜在的应用价值. 关键词： Fano和Kondo共振 自旋极化强度 Fano因子 隧道磁阻     

扶手椅型石墨烯介观环中的持续电流

在紧束缚近似下, 解析求解了扶手椅型边界石墨烯介观环的能量本征值问题, 计算和讨论了不同大小尺寸的介观环中持续电流随Aharonov-Bohm (A-B)磁通的变化, 并证明了能级和持续电流关于磁通变化的周期性和特殊对称性. 研究表明, 持续电流显著地依赖于介观环的几何结构; 零能量附近的能级可以承载较大的持续电流, 而远离零能量的其他能级对持续电流的贡献很小.     

T型双量子点分子Aharonov-Bohm干涉仪的电输运

利用非平衡格林函数方法, 理论研究T型双量子点分子Aharonov-Bohm (A-B)干涉仪的电荷及其自旋输运性质. 通过控制T型双量子点分子内量子点间有无耦合, 能够实现在同一电子能级位置处分别出现共振和反共振状态, 根据此性质, 能将体系设计成量子开关器件. 当将两个完全相同的T型双量子点分子分别嵌入A-B干涉仪两臂中时, 磁通取适当数值, 能够出现完全的量子相消干涉. 通过调节量子点能级、左右两电极间的偏压和Rashba自旋轨道相互作用强度, 可对体系自旋流进行调控. 关键词： 非平衡格林函数 T型双量子点分子 Aharonov-Bohm干涉仪 自旋输运     

层状耦合约瑟夫森双结中的孤子解

基于Sakai-Bodin-Petersen理论，我们求解了对称的双约瑟夫森结的耦合非线性方程组．结果表明，线性化方程组的同相和反相解所对应的两种磁通运动模式也存在于原始的非线性方程组的解中，同时非线性方程组独有的位相锁定的扭折（kinks）形式的磁通运动在低能情况下会演化为孤子解．     

层状耦合约瑟夫森双结中的孤子解

基于Sakai-Bodin-Petersen理论,我们求解了对称的双约瑟夫森结的耦合非线性方程组.结果表明,线性化方程组的同相和反相解所对应的两种磁通运动模式也存在于原始的非线性方程组的解中,同时非线性方程组独有的位相锁定的扭折(kinks)形式的磁通运动在低能情况下会演化为孤子解.     

Effect of the Aharonov-Bohm flux on the magnetic gap soliton in antiferromagnetic chain

Employing the double-sublattice, the coherent state ansatz, and the time-dependent variational principle, we have studied the effects of the Aharonov-Bohm flux on the soliton in one-dimensional antiferromagnetic chain. The results show that the Aharonov-Bohm flux have an effect on the peak, the width, the energy and the spatial configuration of the spin of the soliton.     

Soliton excitations in the molecular-crystal model in a ring threaded by an Aharonov-Bohm flux

Zeitschrift für Physik B Condensed Matter - Effects of the Aharonov-Bohm flux on soliton excitations in the molecular-crystal model with the dispersion term in a one-dimensional ring are...     

On the solution of a “2D Coulomb + Aharonov-Bohm” problem: oscillator strengths in the discrete spectrum and scattering

In this paper we present an exact analytic solution of the Schrödinger equation both inthe discrete and continuous spectra for the combination of a 2D Coulomb potential and theAharonov-Bohm flux. We analyze the influence of the Aharonov-Bohm flux on the energyspectrum of such a system and show that its presence leads to the broadening of theelectron density in the bound states with the given value of the principal quantum number.We have shown that the scattering phase shift, which determines theS-matrix, can be represented as a sum of the Aharonov-Bohm scatteringphase, first obtained by Henneberger, and a “modified” 2D Coulomb phase. We have noticed,that the Aharonov-Bohm scattering phase has a full analogy with the “quantum defect” forsuch a system. We have shown also, that the presence of the Aharonov-Bohm flux affects theradiation spectrum of the electron in this case, and this fact is demonstrated bycalculations of the corresponding oscillator strengths. The explicit analytic expressionfor the scattering cross section on such a system is found in the frame of the eikonalapproach. Obtained formula contains the two exact limiting cases, namely, the “pure” 2DCoulomb scattering as well as the “pure” Aharonov-Bohm effect. The mutual influence of a2D Coulomb potential and the Aharonov-Bohm flux is also discussed.     

Hartman effect in presence of Aharanov-Bohm flux

The Hartman effect for a tunnelling particle implies the independence of group delay time on the opaque barrier width with superluminal velocities as a consequence. This effect is further examined on a quantum ring geometry in the presence of Aharonov-Bohm flux. We show that while tunnelling through an opaque barrier, the group delay time for given incident energy becomes independent of the barrier thickness as well as the magnitude of the flux. The Hartman effect is thereby extended beyond one dimension in the presence of Aharonov-Bohm flux.     

Electron Transport Through Double-Dot Aharonov-Bohm Interferometer in the Kondo Regime

By applying the slave boson technique, we have studied the electron transport through double-dot Aharonov-Bohm interferometer in the Kondo regime. For the system with symmetric quantum dots, the linear conductance is shown to be enhanced by Kondo effect, but it is suppressed in the deep dot level regime in the presence of nonzero magnetic flux. The Aharonov-Bohm oscillations of the conductance are also investigated.     

Path integrals with topological constraints: Aharonov-Bohm effect and polymer entanglements

For Wiener- and Feynman integrals over paths with certain topological properties we compare various methods for explicit calculation. This leads to a one-to-one correspondence between the Aharonov-Bohm effect and a certain polymer entanglement problem. We briefly comment on two generalizations of the Aharonov-Bohm effect. First, we consider this effect due to a closed magnetic flux loop of arbitrary shape; next, we consider the combined effect due to a gas of microscopic magnetic flux loops.     

Conductance in an Aharonov-Bohm Interferometer with Parallel-Coupled Double Dots

We present a theoretical study of the conductance in an Aharonov-Bohm interferometer containing two coupled quantum dots. The interdot tunneling divides the interferometer into two coupled subrings, where opposite magnetic fluxes are threaded separately while the net flux is kept zero. Using the Green function technique we derive the expression of the linear conductance. It is found that the Aharonov-Bohm effect still exists, and when the level of each dot is aligned, the exchange of the Fano and Breit-Wigner resonances in the conductance can be achieved by tuning the magnetic flux. When the two levels are mismatched the exchange may not happen. Further, for some specific asymmetric systems where the coupling strengths between the two dots and the leads are not equal, the flux can change the Fano resonance into an antiresonance, which is absent in symmetric systems.     

Optical properties in a two-dimensional quantum ring: Confinement potential and Aharonov-Bohm effect

Optical properties of a two-dimensional quantum ring with pseudopotential in the presence of an external magnetic field and magnetic flux have been theoretically investigated. Our results show that both of the pseudopotential and magnetic field can affect the third non-linear susceptibility and oscillator strength. In addition, we found that the oscillator strength and the absolute value of the resonant peak of the linear, non-linear and total absorption coefficient demonstrates the Aharonov-Bohm oscillation with magnetic flux, moreover, changes in confinement potential can influence the Aharonov-Bohm oscillation in peak while the resonant peak value of the linear, non-linear and total refractive index changes decreases as magnetic flux increases.     

Aharonov-Bohm effect in spherical billiard

Using Gutzwiller's periodic orbit theory, we study the quantum level density of a spherical billiard in the presence of a magnetic flux line added at its center, especially discuss the influence of the magnetic flux strength on the quantum level density. The Fourier transformed quantum level density of this system has allowed direct comparison between peaks in the level density and the length of the periodic orbits. For particular magnetic flux strength, the amplitude of the peaks in the level density decreased and some of the peaks disappeared. This result suggests that Aharonov-Bohm effect manifests itself through the cancellation of periodic orbits. This phenomenon will provide a new experimental testing ground for exploring Aharonov-Bohm effect.