On the interpretation of the electron anomalous magnetic moment

Guided by a Compton-sized model, we demonstrate that: (a) the magnetic self-energy of the electron, as estimated initially by Rasetti and Fermi, can be directly related to both the sign and the magnitude of the electron anomalous magnetic moment; and (b) the classical expression for the magnetic self-energy of the electron exhibits the same characteristic logarithmic divergence that occurs in QED. This electron model quantitatively reproduces the spin, magnetic moment, and gyromagnetic ratio of the electron, correct to first order in = e² /c. It also relates the quantum-mechanical spin projection angle to the vanishing of the electric quadrupole moment, and it is capable of reproducing point-like scattering behavior.     

电矩张量与旋转带电体的磁矩

基于旋转带电体的磁矩与刚体转动惯量之间的类比关系,引入带电体的一个不同于电四极矩的电矩张量的概念,进而引入标量电矩二次曲面及电矩主轴的概念,借助正交变换及电矩张量矩阵的本征值理论,推导出沿任意方向定轴旋转带电体的磁矩的计算公式及电矩张量的若干性质,并举例说明.     

Fractional Spin of System with Chern–Simons Term Coupled to Polaron

The fractional spin of a system with Chern–Simons (CS) term coupled to a polaron at the quantum level is studied. The Faddeev–Senjanovic (FS) scheme for path-integral quantization of constrained Hamiltonian systems is applied. The quantal conserved angular momentum and the fractional spin at the quantum level of this system are presented based on the quantal Noether theorem. The fractional spin is also presented for the system with Maxwell kinetic term.     

Quantum Symmetry of a Chern–Simons System Coupled to a Polaron

The property of fractional spin of the system with Chern–Simons (CS) term coupled to polaron at the quantum level is studied. According to the rule of path integral quantization for constrained Hamiltonian system in Faddeev–Senjanovic (FS) scheme, this system is quantized. Based on the quantal Noether theorem, the quantal conserved angular momentum and the fractional spin at the quantum level of this system is presented. The fractional spin is also presented in the system including Maxwell kinetic term.     

Magnetic correction to the anomalous magnetic moment of electrons

We investigate the leading order correction of anomalous magnetic moment (AMM) to electrons in a weak magnetic field and find that the magnetic correction is negative and magnetic field dependent, indicating a magnetic catalysis effect for the electron gas. In the laboratory, to measure the g − 2, the magnitude of the magnetic field B is several T, and correspondingly the magnetic correction to the AMM of electron/muon is around 10⁻³⁴/10⁻⁴², therefore the magnetic correction can be safely neglected in the current measurement. However, when the magnitude of the magnetic field strength is comparable with the electron mass, the magnetic correction of the electron's AMM will become considerable. This general magnetic correction to the charged fermion's AMM can be extended to study quantum chromodynamic matter under a strong magnetic field.     

Quantal symmetries in the non-linear σ model with Maxwell and non-Abelian Chern-Simons terms

The quantal symmetry property of the CP1 nonlinear σ model with Maxwell non-Abelian ChernSimons terms in(2+1) dimension is studied.In the Coulomb gauge,the system is quantized by using the Faddeev-Senjanovic(FS) path-integral formalism.Based on the quantaum Noether theorem,the quantal conserved angular momentum is derived and the fractional spin at the quantum level in this system is presented.     

电子自旋不是轨道角动量的相对论效应

根据氢原子的相对论性环电流密度jψ的表示式，指出由该jψ给出的氢原子磁矩公式必然涉及电子自旋磁矩，电子自旋不是轨道角动量的相对论效应。     

Quark Mass Dependence of Nucleon Magnetic Moment and Charge Radii

Understanding hadron structure within the framework of QCD is an extremely challenging problem. Our purpose here is to explain the model-independent consequences of the approximated chiral symmetry of QCD for two famous results concerning the quark structure of the nucleon. We show that both the apparent success of the constituent quark model in reproducing the ratio of proton to neutron magnetic moments and the apparent success of the Foldy term in reproducing the observed charge radius of the neutron are coincidental. That is, a relatively small change of the current quark mass would spoil both results.     

Quark Mass Dependence of Nucleon Magnetic Moment and Charge Radii

Understanding hadron structure within the framework of QCD is an extremely challenging problem. Our purpose here is to explain the model-independent consequences of the approximated chiral symmetry of QCD for two famous results concerning the quark structure of the nucleon. We show that both the apparent success of the constituent quark model in reproducing the ratio of proton to neutron magnetic moments and the apparent success of the Foldy term in reproducing the observed charge radius of the neutron are coincidental. That is, a relatively small change of the current quark mass would spoil both results.     

高电荷态ECR2离子源

介绍了兰州重粒子加速器ＥＣＲ２离子源的结构特点，给出该离子源的调试结果。     

Quantal symmetries in the non-linear σ model with Maxwell and non-Abelian Chern-Simons terms

The quantal symmetry property of the CP1 nonlinear （y model with Maxwell non-Abelian Chern- Simons terms in （2＋1） dimension is studied. In the Coulomb gauge, the system is quantized by using the Faddeev-Senjanovic （FS） path-integral formalism. Based on the quantaum Noether theorem, the quantal conserved angular momentum is derived and the fractional spin at the quantum level in this system is presented.     

Status of the Fermilab muon （g-2） experiment

The New Muon （g-2） Collaboration at Fermilab has proposed to measure the anomalous magnetic moment of the muon, αμ, a factor of four better than was done in E821 at the Brookhaven AGS, which obtained αμ = [116592089（63）] × 10^-11 ±0.54 ppm. The last digit of a, is changed from the published value owing to a new value of the ratio of the muon-to-proton magnetic moment that has become available. At present there appears to be a difference between the Standard-Model value and the measured value, at the ≌ 3 standard deviation level when electron-positron annihilation data are used to determine the lowest-order hadronic piece of the Standard Model contribution. The improved experiment, along with further advances in the determination of the hadronic contribution, should clarify this difference. Because of its ability to constrain the interpretation of discoveries made at the LHC, the improved measurement will be of significant value, whatever discoveries may come from the LHC.     

Operators of observables for a neutral particle with anomalous magnetic moment in an electromagnetic field

The explicit form of operators of kinetic momenta and spin projection for a neutral particle with an anomalous magnetic moment in constant homogeneous electromagnetic field is found. The possible applications of the obtained results in neutrino physics are considered.     

Status of the Fermilab muon(g-2)experiment

The New Muon(g-2)Collaboration at Fermilab has proposed to measure the anomalous magnetic moment of the muon,aμ,a factor of four better than was done in E821 at the Brookhaven AGS,which obtained aμ =[116592089(63)]×10-11±0.54 ppm.The last digit of aμ is changed from the published value owing to a new value of the ratio of the muon-to-proton magnetic moment that has become available.At present there appears to be a difference between the Standard-Model value and the measured value,at the(≈)3 standard deviation level when electron-positron annihilation data are used to determine the lowest-order hadronic piece of the Standard Model contribution.The improved experiment,along with further advances in the determination of the hadronic contribution,should clarify this difference.Because of its ability to constrain the interpretation of discoveries made at the LHC,the improved measurement will be of significant value,whatever discoveries may come from the LHC.     

Letter: Spin Polarised Magnetized Cylinders in Torsioned Spacetime

A Spin-polarised cylindrically symmetric exact class of solutions endowed with magnetic fields in Einstein-Cartan-Maxwell gravity is obtained. Application of matching conditions to this interior solution having an exterior as Einstein's vacuum solution shows that for this class of metrics the Riemann-Cartan (RC) rotation vanishes which makes the solution static. Therefore we end up with a magnetized static spin polarised cylinder where the pressure along the symmetry axis is negative.     

含Chern-Simons项的旋量电动力学的量子正则对称性

构造了含Chern-Simons(CS)项的旋量电动力学的规范变换生成元.按约束Hamilton系统的Faddeev-Senjanovic(FS)路径积分量子化方案,给出了该系统Green函数的相空间生成泛函;导出了正则Ward恒等式;分析了系统的量子守恒角动量,指出它具有分数自旋性质.     

Electronic structure and magnetic properties of SmCo7-x Tix

Electronic structure of SmCo7-xTix alloy has been studied by means of the spin-polarized MS-X( method. It is shown that a few of electrons are transferred to Sm(5d) orbital due to orbital hybridization between Sm and Co atoms. The exchange interaction between 5d-3d electrons is stronger, which is the main reason resulting in the long-range ferromagnetic order between Co and Sm atoms. The Curie temperature of SmCo7-xTix is generally lower than that of pure Co metal, which may be explained by the weaker average of coupling strength between Co sites due to some negative exchange couplings occurring mainly at 2e site. The calculated results for the Sm5Co28Ti6 cluster may lead to a better understanding of why SmCo7-xTix is stable phase. Since the negative interaction of 2e sites weakens and the bonding at EF strengthens with increasing Ti concentration, which result in the decrease in the free energy of the alloy, the stable ferromagnetic order forms inside SmCo7-xTix. Considering the localization of 4f states and 5d moment arising from the orbital hybridization, the calculated moment is 9.47μB per formula unit that is in agreement with experiments.     

电子比荷测量的实验改进

采用平均效应求磁场强度的理论描述方法,研究了电子比荷测量实验,给出了比较理想的电子比荷测量实验结果.     

Unusual Charge Transport and Spin Response of Doped Bilayer Triangular Antiferromagnets

Within the t-J model, the charge transport and spin response of the doped bilayer triangular antiferromagnetare studied by considering the bilayer interaction. Although the bilayer interaction leads to the band splitting in theelectronic structure, the qualitative behaviors of the physical properties are the same as in the single layer case. Theconductivity spectrum shows the low-energy peak and unusual midinfrared band, the temperature-dependent resistivityis characterized by the nonlinearity metallic-like behavior in the higher temperature range and the deviation from themetallic-like behavior in the lower temperature range and the commensurate neutron scattering peak near the half-fillingis split into six incommensurate peaks in the underdoped regime, with the incommensurability increasing with the holeconcentration at lower dopings, and saturating at higher dopings.