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1.
Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated. Both spindependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering. It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase. However spin-down transmission and reflection coefficients appear periodic AC oscillations. The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns. In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field. 相似文献
2.
Oscillations of the spin-polarized conductance controlled by a uniform magnetic field in a modified Aharonov-Bohm ring is studied with use of one-dimensional quantum wave guide.Its expression at zero temperature is obtained as a function of the flux penetrating the ring and the magnetic field.It has been found that there are two kinds of polarized conductance extremas for a given Fermienergy.As Zeemann energy of spin-polarized electron in the stub is varied.one kind of extrema exhibits continuous phase shift .However,another is locked at particular values of phase shift and it can only change abrouptly from a maxima to a minima when Zeemann crosses the level of the bound state of isolated stub.This is a different mehanism for abrupt change phase of conductance osillations. 相似文献
3.
The relationship between Compton scattered photon counts per unit mass and the content of a component in a binary powder mixture is deduced based on the Compton scattering theory. This relationship can be regarded linear after some approximations. The scattered photon counts per unit mass increases faster with the content when the difference of the atomic numbers of the two components in the binary powder mixture is larger. The relationship was verified with Compton scattering experiments on a series of Ni-Cu and Fe-C binary powder mixtures. The method of using this linear dependene of scattered photon counts on the content of a binary powder mixture to ascertain the component content in a binary mixture was introduced. 相似文献
4.
XIANG Yu-min 《重庆大学学报(英文版)》2008,7(3):210-215
To determine the motion of a charged particle in a magnetic field produced by a current flowing along a long column conductor, the equation of the motion was established on the basis of Lorentz force. Qualitative analysis and quantitative solutions demonstrated that the motion contains nonlinear oscillation. The oscillation can be treated as the perturbation of the helical motion, Which the particle undergoes in a special condition. The general motion is superposition of two helixes, one as an axis spiraled by another. It is proven that the oscillation is stable. 相似文献
5.
The gauge invariance of the electromagnetic field in gravitational field is an important question. We prove d' Alembert equation in gravitational field with gauge invariance under the Lorentz condition. Using the kinematic equation of photon in normal static and spherically symmetric gravitational fields, we deduce the orbital equation of photon. As a special example, we explicate the deduction and discussion about the deviation angular of light in Reissner-Nordstrom space-time. 相似文献
6.
INTRODUCTION In the theory of partial differential equations,Schwartz distribution theory and Sobolev spacesplay a very important role. But one shortcoming ofdistribution theory, however, is its inability to solvenonlinear problems because the product of distri-butions may not be a distribution. The need to de-fine the product of distributions also arises withproblems in Dirac’s quantum theory of an elec-tromagnetic field. It is impossible to introduce anassociate multiplication i… 相似文献
7.
The interactions of laser field with plasma are studied by using the analog model of gravity. The interactions of laser field with plasma are regarded as an equivalent effective geometry. An effective metric for a plasma electron is developed. Validity of the metric is confirmed in the limit of non-relativity. The three-dimensional equation of motion for a plasma electron is derived from the general covariant equation of motion. The ponderomotive force and the Abraham＇s force are directly obtained from the three-dimensional equation. 相似文献
8.
We investigate alternating response of the spin current in a quantum dot system coupled to a normal metal electrode,to which an alternating driving voltage and a pumping rotating magnetic field are applied.The expression of the time-averaged spin current and its differential is obtained based on a non-equilibrium Green's function method.We find that for a given rotating frequency,the spin current increases rapidly and appears to have small steps when the driven frequency increases.As the driven frequency is further increasing,the spin current can be significantly enhanced and approaches a stable value.The photon-assisted processes bring about interesting features of spin current.The influence of the gate voltage and temperature on the spin current is examined in detail. 相似文献
9.
使用试错法加快扩频通信伪随机码捕获 总被引：1，自引：0，他引：1
An optimun search algorithm for the coherent acquisition in direct-sequence spread-spectrum （DSSS） receivers is proposed and analyzed in this paper. The system consists of two major parts： a phase region estimator and a phase alignment detector. We use an auxiliary sequence to correlate the incoming signal in the phase region estimator. Since the cross-correlation value between the auxiliary sequence and the incoming PN signal has linear magnitude, and can provide the direction for the phase updating, an optimum search algorithm, try and error method, can be adopted to obtain the phase region information of the incoming signal. The mean acquisition time is derived through the signal flow graph theory. The time is compared with that of the conventional serial search scheme, and the results show that the proposed scheme can achieve coarse acquisition significantly faster than the conventional scheme. 相似文献
10.
The conductance and polarization are studied in one-dimensional ballistic quantum wire with both Rashba and Dresselhaus spin-orbit interactions.Two kinds of structures are considered in the present work,one with mixture of two interactions and the other with sequence structure of them.We find that the conductance and polarization are strongly affected by these two interactions.With both interactions we obtain a multi-peak contour of spin polarization and a dramatic oscillation pattern of spin conductance,which are due to the different combination of the two spin-orbit interactions. 相似文献
11.
1 Introduction Since some experi ments made by Yacoby,et al.[1],and Schuster ,et al.[2],that first measured electrontransmission phase through a quantum dot ( QD) ,phase sensitive transports in open mesoscopic ringwith a QD have been extensively investiga… 相似文献
12.
SHI Yao ming XU Shi Yue CHEN Hang de 《上海大学学报(英文版)》1999,3(4):274-278
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｒｅｃｅｎｔｌｙ,ａｓｅｒｉｅｓｏｆｅｘｐｅｒｉｍｅｎｔｓｂｙＹａｃｏｂｙｅｔａｌ．［１］ａｎｄＢｕｋｓｅｔａｌ．［２］ｒｅｐｏｒｔｅｄｓｏｍｅｍｅａｓｕｒｅｍｅｎｔｓｏｆｅｌｅｃｔｒｏｎｔｒａｎｓｍｉｓｓｉｏｎｐｈａｓｅｉｎｒｅｓｏｎａｎｔｔｕｎｎｅｌｉｎｇｔｈｒｏｕｇｈａｑｕａｎｔｕｍｄｏｔ（ＱＤ）ｗｈｉｃｈｉｓｉｎｓｅｒｔｅｄｉｎｔｏｏｎｅａｒｍｏｆａｎＡｈａｒｏｎｏｖＢｏｈｍ（ＡＢ）ｒｉｎｇ．ＴｈｅｃｏｎｄｕｃｔａｎｃｅｔｈｒｏｕｇｈｔｈｅＡＢｒｉｎｇｗ… 相似文献
13.
1IntroductionQuantumtransport in mesoscopic systems has beenextensively investigated in the past two decade[1].Since Wees ,et al.[2]and Wharam,et al.[3]discov-ered the phenomenon of conductance quantization ofan electron through a narrow two-di mensional con-striction,there have been a number of other works ,which are concentrated on studying electron scatteringfrom i mpurities in a narrow quantum conductorwire[4-10].Bagwell and Avishai ,et al.[4-6]have exam-ined the influences of scattering … 相似文献
14.
量子波导理论研究不仅是对基础物理而且对量子器件研究具有重要意义,我们采用模匹配方法,研究了非均匀磁场下开放的四端量子波导中的电子输运性质。结果表明,从一端入射的电子可以透射到两个与之垂直的输出端和一个与之平行的输出端。在没有外加磁场的情况下,两个垂直输出端的输运几率是相同的,但垂直端与水平端的输运几率不同;在外加磁场下,由于磁边缘态效应,两个垂直输出的输运几率也有着相当大的差别。 相似文献
15.
Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated.Both spin-dependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering.It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase.However spin-down transmission and reflection coefficients appear periodic AC oscillations.The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns.In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field. 相似文献
16.
研究了双磁垒量子结构中,磁场强度和偏压大小对电子自旋极化输运的影响。结果表明:零偏压下,电子在反平行等强磁垒结构中输运不会产生自旋极化;电子传输的阈值能量随磁场强度或偏置电压的增大而增大;在一定的磁场强度和偏压大小下,比较由半导体InAs和GaAs两类材料构成的量子结构中电子输运自旋极化度,发现它们的电子输运自旋极化度都随入射能量的增大而呈振荡衰减趋势,朗德有效因子高的InAs材料比GaAs的自旋极化度高出一个数量级。 相似文献
17.
李国锋 《赣南师范学院学报》2009,30(3):52-54
研究一束自旋极化电子在准一维系统中的榆运,输运电子经过一个势阱和SOI共同作用的散射区．研究发现经过散射后电子自旋翻转的概率与费米能廓、势阱的深度Vo、自旋轨道耦合的强度λR以及各通道的能级Ej,并且翻转概率具有周期振荡特性,即随散射区的长度呈周期性变化． 相似文献