Effects of electron-interface-phonon interactions on interactions between electrons in double-heterostructures

Effects of electron-interface-phonon interaction on the interaction between electrons in double heterostructures are considered. It is found that the interaction potential between electrons caused by each of four interface-phonon modes is different. For electrons moving at the two interfaces of double heterostructure, the interaction energies of the electrons produced by the interaction with antisymmetric modes are positive which indicate that the forces between electrons are repulsive. The interaction energies caused by interaction with symmetric modes are negative and the forces are attractive. The resultant of the forces are attractive and become larger when the width of potential barrier decreases for InAs/GaSb/InAs double heterostructure.     

带间耦合相互作用对MgB2超导体同位素效应指数的影响

在弱耦合极限下考虑带间相互作用,得到了二带s-波超导体临界温度Tc的公式及同位素效应指数的公式。在此模型中,耦合相互作用在每一带中包括两部分:电子-声子相互作用和非电子-声子相互作用,当Tc≈40K时,在弱耦合机制中得到MgB2的同位素效应指数αB=0.3,并且带间的电子-声子相互作用比非电子-声子作用对同位素效应指数的影响大。     

用NMR技术研究蛋白质-配体相互作用

蛋白质-配体相互作用的研究对理解生命过程、药物设计和药物筛选具有相当重要的科学意义和巨大的经济价值. NMR是研究蛋白质-配体相互作用的最有用的技术之一,有着显著的优势. 本文综述了近年来国际上用NMR技术研究蛋白质-配体相互作用的发展状况和趋势,先介绍表征蛋白质-配体相互作用的重要参数,然后介绍如何判断蛋白质或配体与复合物的化学交换类型以及所能获得的有关蛋白质-配体相互作用的信息,最后介绍具体用于研究蛋白质-配体相互作用的若干NMR技术以及基于NMR的药物筛选技术.     

The symmetric and antisymmetric superexchange interactions in spin-Peierls system

The influences of Dzyaloshinskii Moriya （DM） interaction and Kaplan-Shekhtman-Entinwohlman-Aharony （KSEA） interaction on the dimerization of a spin-Peierls system are investigated theoretically by using the Lanczos numerical method. The ground state of the spin-Peierls system is still dimerized phase when both of the DM and the KSEA interactions have the same value with Heisenberg interaction. It is found that the KSEA interaction and uniform DM interaction are always against systemic dimerization, but the staggered DM interaction acts in favour of dimerization. Furthermore, the influences of the DM and the KSEA interactions are also studied in terms of the ground state index rate and the energy gap index rate of the dimerized Heisenberg system. The results show that the DM interaction makes the index rates larger, while the KSEA interaction makes them smaller.     

具有对称和反对称超交换相互作用的一维spin-Peierls系统的基态行为

采用Lanczos数值计算方法研究了具有Dzyaloshinskii-Moriya（DM）相互作用和Kaplan-She khtman-Entin-Wohlman-Aharony（KSEA）相互作用的一维spin-Peierls（s-P）系统的基态 行为.计算结果发现KSEA相互作用总是不利于系统二聚化，并且它还影响DM相互作用对系统 二聚化的贡献，甚至可以抵消其作用；在某些特定条件下, KSEA和DM的共同作用可以破坏系 统的二聚化基态而转化为均匀基态. 关键词： DM相互作用 KSEA相互作用 二聚化     

Off-Diagonal Long-Range Order (ODLRO) Solitons and Superconductivity

The analogue between monopole-fermion interaction in the spontaneously broken gauge theory and phonon-electron interaction in the theory of superconductivity is studied. It is shown that both monopole-fermion interaction and phonon-electron interaction are characterized by the existence of the off-diagonal long-range order. Starting from the analogue between monopole-fermion interaction and phononelectron interaction the possible relevance of condensed solitons to superconductivity is also discussed.     

Fermi-liquid theory of the electron-electron interaction effects in disordered metals

Influence of the arbitrary strong interaction between the electrons on the thermodynamic and transport properties of disordered metals is considered. The contributions of the interaction in the diffusion channel to all of the quantities are shown to depend on only one Fermi-liquid interaction constant (to take interaction in the cooper channel into account one has to include one constant more). It is found very convenient to divide all of the diffusion corrections on the parts which correspond to different values of the total spin of the electron and hole j:j = 0 and j = 1. It is the interaction with j=1 that leads to magnetic field dependence of the diffusion contributions. In the presence of spin-dependent scattering of the electron only the contribution related to the interaction with j=0 are important. These contributions to all of the quantities are universal, i.e. they do not depend on any interaction constant.     

Exact Solution to Spin Squeezing of the Arbitrary-Range Spin Interaction and Transverse Field Model

We investigate spin squeezing effects of trapped ions in an off-resonance optical potential system using the arbitrary range spin-spin interaction and transverse Geld model.The collective spin noises at any time are analyzed exactly.The general expression of spin squeezing factor is presented for arbitrary-range spin interaction.For the nearest-neighbor and next-nearest neighbor spin interaction model,the analytic solutions are reduced from the general expressions.It is shown that the maximum spin squeezing is enhanced for the general arbitraryrange spin interaction compared with the nearest-neighbor interaction model as the long-range interaction with arbitrary sites enforces stronger correlation.     

Machian Mechanics with Isotropic Inertia

A nonrelativistic theory is discussed here which contains an interaction which produces isotropic inertia for anisotropic matter distributions. The interaction is a 4-body interaction and it is explained why it is necessary to have this type of interaction. The consequences of the theory are discussed for celestial mechanics including the predicted perihelion precession. Frame dragging effects are calculated and compared with other theories. Possible ways to extend the theory to noninstantaneous interactions are briefly discussed. This theory demonstrates that Mach's principle in the form considered here is not necessarily inconsistent with isotropic inertia.     

Evidence of many-particle interactions in two-dimensional charge-stabilized colloidal crystals

Electrostatic interaction in two-dimensional colloidal crystals obeying the nonlinear Poisson-Boltzmann equation is studied numerically. The force constants which are the coefficients of the energy quadratic form of the crystal are obtained. Significant discrepancy between the results of computer experiments and predictions of the harmonic crystal theory based on the idea of pairwise interaction has been detected. Two simple parameters are introduced for uniform quantitative estimation of many-particle effects and validity of the approximation of nearest-neighbor interaction. It is shown that the contribution of many-particle interaction into the total electrostatic interaction in colloidal crystals is significant for a broad range of crystal lattice constants and particles' sizes.     

Skyrme张量相互作用对可能的等待点原子核β衰变半衰期的影响(英文)

使用基于Skyrme相互作用的HFB+QRPA模型研究N~82和126的同中子异位素链的β-衰变的半衰期。在计算中所使用的张量相互作用和同位旋标量（IS）对相互作用都是很好地被约束了的。比较了张量相互作用和IS对相互作用对半衰期的影响。IS对相互作用的强度与相应的同位旋矢量（IV）对相互作用的强度相当时,对N~82和126的同中子异位素链中有大的中子过剩的原子核的半衰期影响很微弱。而张量相互作用采用最近约束的强度时对半衰期的影响非常显著。The β-decay half-lives of N ~ 80 and 126 isotonic chains are calculated with HFB+QRPA models based on Skyrme force. In the calculations, the well constrained Skyrme tensor interaction and isoscalar spin-triplet (IS) pairing interaction are included so that to study their effects on the half-lives. The effects of tensor interaction and IS pairing interaction on the half-lives are compared. The IS pairing interaction with strength similar to that of isovector (IV) one produces only a trivial effect in N ~82 nuclei, and N ~126 nuclei with big neutron excess. While the tensor interaction with presently constrained strengths produces an obvious effect.     

视听双任务条件下注意对视觉和听觉掩蔽效应的影响

在视听交互环境中,当视觉和听觉掩蔽刺激同时感知时,对视听觉的相互作用及掩蔽变化问题进行了实验研究。将视听交互场景按注意状态分类,实验测量了不同场景中视觉和听觉掩蔽阈值的变化,讨论了不同视觉和听觉掩蔽刺激的相互影响。实验结果发现对比单任务实验的阈值,不同视听交互环境中视觉和听觉的掩蔽阈值会产生相应变化。由实验结果可以推论视听交互环境中注意分配影响视觉和听觉掩蔽效应,并且视听掩蔽刺激的相互作用会进一步影响视觉和听觉唤起的注意。      

Solitary excitations in one-dimensional ferromagnetic spin chains with biquadratic exchange interaction

By using the traveling wave method, the solutions of the elliptic function wave and the solitary wave are obtained in a ferromagnetic spin chain with a biquadratic exchange interaction, a single ion anisotropic interaction and an anisotropic nearest neighbour interaction. The effects of the biquadratic exchange interaction and the single ion anisotropic interaction on the properties (width, peak and stability) of the soliton are investigated. It is also found that the effects vary with the strengths of these interactions.     

Spin polarization in parallel double dots with spin-orbit interaction

Spin polarization in parallel double quantum dots embedded in arms of Aharonov-Bohm interferometer is investigated. The spin-orbit interaction exists in quantum dots. We find that the spin polarization is quite large even with a weak spin-orbit interaction. The direction and the strength of the spin polarization are well controllable and manipulatable by simply varying the strength of spin-orbit interaction or the energy levels in quantum dots. Moreover, electron-electron interaction strengthens the spin accumulation when the energy levels of the two quantum dots are identical. As the energy levels are unequal, electron-electron interaction cannot increase the spin accumulation. It is worth mentioning that the device is free of a magnetic field or a ferromagnetic material and it can be easily realized with present technology.     

On the first order valence transition in SmS

The valence transition in SmS is investigated on the basis of a model which incorporates the Falicov-Kimball (F-K) interaction, f-d hybridization and electron-phonon interaction. We find that the transition is of first order even in the absence of electron-phonon interaction if the F-K interaction is sufficiently strong. Electron-phonon interaction makes the first order transition possible for a weaker F-K interaction. The effect is further enhanced if phonon-induced f-f and f-d coupling are simultaneously present. All calculations are done for finite temperature and the temperature dependence of the transition is found to be in agreement with the phase diagram of SmS.     

Microscopic calculation of the fermi liquid interaction constants for electrons in the surface inversion layer of a semiconductor

The leading Fourier coefficients of both the spin dependent and spin independent Landau interaction function of a quasi-two-dimensional electron gas are evaluated. Three different schemes for calculating the interaction function are studied for both a pure two-dimensional Coulomb interaction and an effective electron-electron interaction appropriate to the actual metal-insulator-semiconductor structure.     

Effects of electric field and size on the electron-phonon interaction in a spherical quantum dot with impurity

The effects of electric field and size on the electron-phonon interaction with an on-center impurity in a Zn_1?x Cd _x Se/ZnSe spherical quantum dot are studied, taking into account the interactions with confined, half-space and surface optical phonons. In addition, the interaction between impurity and phonons has also been considered. The results show that the electron-confined, electron-half-space, and electron-surface optical phonon interaction energies are all negative. The electron-confined optical phonon interaction energy is weakened by the electric field, but the electron-half-space and electron-surface optical phonon interaction energies are strengthened by it. In particular, the electron-surface optical phonon interaction depends strongly on the electric field, and it will vanish when the electric field is absent. It is also found that the electron-confined optical phonon interaction and electron-impurity “exchange” interaction energies reach a peak values as the quantum dot radius increases and then gradually decrease, but the electron-half-space optical phonon interaction energy exponentially quickly approaches 0 as the quantum dot radius increases.     

The effects of electron–phonon interaction on anisotropic RKKY interaction in graphene nanoribbon

We study the Ruderman–Kittle–Kasuya–Yosida (RKKY) interaction in doped armchair graphene nanoribbon. The effects of both external magnetic field and electron-Holstein phonon on RKKY interaction have been addressed. RKKY interaction as a function of distance between localized moments has been analyzed. It has been shown that a magnetic field along the z-axis mediates an anisotropic interaction which corresponds to a XXZ model interaction between two magnetic moments. In order to calculate the exchange interaction along arbitrary direction between two magnetic moments, we should obtain both transverse and longitudinal static spin susceptibilities of armchair graphene nanoribbon in the presence of electron-phonon coupling and magnetic field. The spin susceptibility components are calculated using the spin dependent Green’s function approach for Holstein model Hamiltonian. The effects of spin polarization on the dependence of exchange interaction on distance between moments are investigated via calculating correlation function of spin density operators. Our results show the influences of magnetic field on the spatial behavior of in-plane and longitudinal RKKY interactions are different in the presence of magnetic field.     

Time-varying interaction leads to amplitude death in coupled nonlinear oscillators

A new form of time-varying interaction in coupled oscillators is introduced. In this interaction, each individual oscillator has always time-independent self-feedback while its interaction with other oscillators are modulated with time-varying function. This interaction gives rise to a phenomenon called amplitude death even in diffusively coupled identical oscillators. The nonlinear variation of the locus of bifurcation point is shown. Results are illustrated with Landau–Stuart (LS) and Rössler oscillators.     

Proton radioactivity with a Yukawa effective interaction

The half-lives of proton radioactivity of proton emitters are investigated theoretically. Proton-nucleus interaction potentials are obtained by folding the densities of the daughter nuclei with a finite-range effective nucleon-nucleon interaction having Yukawa form. The Wood-Saxon density distributions for the nuclei used in calculating the nuclear as well as the Coulomb interaction potentials are predictions of the interaction. The quantum mechanical tunneling probability is calculated within the WKB framework. These calculations provide reasonable estimates for the observed proton radioactivity lifetimes. The effects of neutron-proton effective mass splitting in neutron-rich asymmetric matter as well as the nuclear matter incompressibility on the decay probability are investigated.