Controlling Three-Dimensional Electron-Electron Correlation via Elliptically Polarized Intense Laser Field

The three-dimensional electron-electron correlation in an elliptically polarized laser field is investigated based on a semiclassical model. Asymmetry parameter α of the correlated electron momentum distribution is used to quantitatively describe the electron-electron correlation. The dependence of α on ellipticity ε is totally different in three directions. For the z direction(major polarization direction), α first increases and reaches a maximum at ε = 0.275, then it decreases quickly. For the y direction in which the laser field is always absent, the ellipticity has a minor effect, and the asymmetry parameter fluctuates around α =-0.15. However, for the x direction(minor polarization direction), α increases monotonously with ellipticity though starts from the same value as in the y direction when ε = 0. The behavior of α in the x direction actually indicates a transformation from the Coulomb interaction dominated correlation to the laser field dominated correlation. Therefore, our work provides an efficient way to control the three-dimensional electron-electron correlation via an elliptically polarized intense laser field.     

Details of Electron-Electron Correlation of Pe Helium States by Partial-Wave Analysis

The N = 2 and N = 3 series of the ¹P^e doubly excited helium states are investigated by a partial-wave analysis, and by inspecting the one-body densities and the shape-densities. Many features in the anisotropism of the electronic cloud, in the geometric configuration, and in the details of radial-radial correlation are found. A comparison between the ²P^e and ³P^e states is made.     

An Analytical Approach on Mesoscopic Transport Involving with Electron-Electron Interaction

In this paper, we try to present a way in terms of which one can analytically obtain the Hartree self-consistent potential instead of computing it by the numerical iterative procedure as usual, which is convenient for us to describe the current flow through a mesoscopic conductor. In our treatment, we expand the action function S(x) by Planck constant ħ, then the self-consistent potential and the wavefunction can be solved analytically order by order starting from the Poisson equation and quantum Hamilton-Jacobian equation, the differential conductance and quantum capacitance can thus be obtained naturally. In our paper, we show the quantum corrections up to the second order, and the electron-electron interaction is considered only at the Hartree approximation level.     

Analytical Holographic Superconductor with Backreaction Using AdS 3/CFT 2

The holographic model for a two-dimensional superconductor has been investigated by considering the three-dimensional gravity in the bulk. To find the critical temperature, we used the Sturm–Liouville variational method. Where as the same method is applied for calculating the condensation of the dual operators on the boundary. We included the back reactions on the metric by a combination of the perturbation method of the fields with respect to the small parameter and then applying the variational integrals on the resulting equations of the motion. The critical temperature has been successfully obtained on the backreaction effects, and we showed that it dropped with a rise in the backreaction of the fields, and it makes the condensation harder. We can use our analytical results to support the numerical data which was reported previously.     

4M-2000A高温超导电缆制冷系统

介绍了我国新研制成的首条双通道热绝缘型 4 M- 2 0 0 0 A高温超导电缆制冷系统。该系统由 G- M制冷机提供制冷量 ,过冷液氮为冷却介质 ,通过液氮泵循环 ,组成一个闭式循环制冷系统。给出了制冷系统的调试结果。系统上装有温度、压力、流量、液位等测量仪表 ,并备有一个减压抽空系统 ,以附加提供制冷量     

An ab-initio Investigation: The Physical Properties of ScIr2 Superconductor

Physics of the Solid State - Using ab initio technique the physical properties of ScIr2 superconductor have been investigated with Tc 1.03 K with a MgCu2-type structure. We have carried out the...     

Pair-Breaking Critical Current Density of Two-Band Superconductor MgB2

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4M-2000A超导电缆小型制冷系统的设计计算

为了配合 4 M- 2 0 0 0 A超导电缆系统的研制 ,并为 30 M- 2 0 0 0 A超导电缆制冷系统设计、计算提供实际试验值和运行经验 ,设计、建立了 4 M- 2 0 0 0 A超导电缆小型制冷系统。文中叙述了 4 M- 2 0 0 0 A超导电缆制冷系统的设计要求、系统流程、设计概算 ,制冷系统的主要设备介绍以及调试结果等。     

Pair-Breaking Critical Current Density of Two-Band Superconductor MgB2

Temperature dependence of tbe pair-breaking critical current density of MgB2, jd（T）, is studied using a two-band Ginzburg-Landau theory. The results are shown to be in good agreement with experimental data for the superconducting magnesium diboride MgB2.     

MgB_2超导体输运特性的研究

文中对 Mg B2 超导体的制备过程 ,对其同位素效应、电阻率、I- V曲线、热电势、电导涨落效应、能隙、霍尔效应、热重 -差热分析实验等输运特性进行了较全面的综述 ,并讨论了在 Mg B2 超导体基础上的元素替代效应。     

Stckelberg Holographic Superconductor Models with Backreactions

We study the Stckelberg holographic superconductors away from the probe limit.We find that the backreaction of the spacetime can bring richer physics in the phase transition.Moreover we observe that the ratio ωg/Tc changes with the strength of the backreaction and is not a universal constant.     

MgB2颗粒超导体临界电流的温度特性研究

通过制备MgB2/MgO超导复合材料,获得了典型的MgB2弱连接颗粒超导体,并测量了该样品在不同温度下的Ⅰ-Ⅴ特性曲线.在Ⅰ-Ⅴ曲线中,我们发现:当电流超过临界电流时,电压随着电流先是缓慢的增长,在电流升到一定值时,电压有一个很陡的突变.我们对这一变化进行了研究,认为这是由于MgO杂质使MgB2的晶界效应增强所引起的.该样品的临界电流和温度的关系满足:jc(T)∝(1-T/Tc)1/3,利用三维Josephson结网络系统的渗流模型进行计算发现,当颗粒超导系统处于非均匀状态时,临界电流和温度满足关系式jc(T)∝(1-T/Tc)4/3,这一结果和我们的实验符合的非常好.     

Reentrant Orbital Effect against Superconductivity in the Quasi-Two-Dimensional Superconductor NbS2

JETP Letters - We derive an integral equation for the superconducting gap, which takes into account the quantum nature of electron motion in a parallel magnetic field in a quasi-two-dimensional...     

Tunneling Conductance in dx2-y2+idxy Mixed Wave Superconductor Graphene Junctions

Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of normal metal/d_x²-y²+id_xy mixed wave superconductor graphene junctions. It is found that the conductance spectra vary strongly with the orientation of the gap and the amplitude ratio (Δ₁/Δ₀) of two components for d_x²-y²+id_xy mixed wave. The zero bias conductance isnearly 2 and the conductance peak vanishes in doped graphene forα=0 and Δ₁/Δ₀=1. The conductance increases with increasing the amplitude ratio of two components for α=π/4 and Δ₁/Δ₀=1. The ZBCP becomesobservable wide with 1F/Δ₀<100 for α=π/4 and Δ₁/Δ₀=1. This property is different from that in normal metal/d_x²-y² wave superconductor graphenejunctions.     

制冷机冷却型超导磁体杜瓦的研制

介绍了带制冷机冷却的超导磁体系统杜瓦的设计、制作及实验结果分析。杜瓦采用 4 0 K、10 K双制冷屏结构 ,其室温磁场孔径为 75 mm,长 4 15 m m。试验结果为 :液氦蒸发率为 0 .6 9升 /天 (在 2 0天连续试验期内 ) ,优于合同规定的指标 (2 .4升 /天 )。双制冷屏由一台双级 G- M制冷机冷却 ,工作时一级冷屏温度为 35 K,二级冷屏温度为 7.0 K。磁体系统的磁场强度为 3T,满足了用户的使用要求     

The c—Axis Infrared Conductivity of a dx^2—y^2— Wave Superconductor with the Hopping Assisted by the Spin Fluctuations

A theory of the c-axis infrared conductivity of a dx^2-y^2- wave superconductor due to the competition between the interlayer direct hopping and the hopping assisted by the spin fluctuations has been developed.The prediction of our theory captures the main feature of the experiment.Thus we argue that the anomalous behavior of the c-axis infrared conductivity of the underdoped cuprates in superconducting state may be properly understood within the theory.     

正常金属d_(x~2-y~2)+id_(xy)混合波超导结中的隧道谱

在Blonder-Tinkham-Klapwijk散射理论框架下,通过求解Bogoliubov-deGennes方程,计算正常金属dx2-y2+idxy混合波超导结中的准粒子输运系数和隧道谱。研究表明:隧道谱中的电导峰位置强烈地依赖电子的入射角、超导的晶轴方位和dxy波分量的强度。