自旋为1粒子在旋转磁场中的几何相位和动力学相位(英文)

文章研究了自旋为1的粒子在旋转磁场中的几何相位和动力学相位.推导出如何计算自旋为1的粒子在绝热和非绝热演化中的几何相位和动力学相位公式,并利用这些公式计算其相位.最后我们讨论了三种情况下的Berry相位,当考虑ω1<<ω时,系统处于绝热近似,此时,几何相位就是Berry相位.     

Polar-Core Spin Vortex of Quasi-2D Spin-2 Condensate in a Flat-Bottomed Optical Trap

Motivated by the recent experiments realized in a flat-bottomed optical trap [Science 347(2015) 167;Nat. Commun. 6(2015) 6162], we study the ground state of polar-core spin vortex of quasi-2D spin-2 condensate in a homogeneous trap plus a weak magnetic field. The exact spatial distribution of local spin is obtained and the vortex core are observed to decrease with the growth of the effective spin-spin interaction. For the larger effective spin-spin interaction, the spatial distribution of spin magnitude in spin-2 condensate we obtained agrees well with that of spin-1 condensate in a homogeneous trap, where a polar-core spin vortex was schematically demonstrated as a fully-magnetized planar spin texture with a zero-spin core. The effective spin-spin interaction is proportional to both the bare spin-spin interaction and the radius of the homogeneous trap, simultaneously. Thus the polar-core spin vortex we obtained can be easily controlled by the radius of the trap.     

Hall Conductivity as the Topological Invariant in the Phase Space in the Presence of Interactions and a Nonuniform Magnetic Field

JETP Letters - The quantum Hall conductivity in the presence of constant magnetic field may be represented as the topological TKNN invariant. Recently, the generalization of this expression has...     

Casimir Effect for a Massless Spin-3/2 Field in Minkowski Spacetime

The Casimir effect has been studied for various quantum fields in both flat and curved spacetimes. As a further step along this line, we provide an explicit derivation of Casimir effect for massless spin-3/2 field with periodic boundary condition imposed in four-dimensional Minkowski spacetime. The corresponding results with Dirichlet ard Neumann boundary conditions are also discussed.     

The Wigner Functions for a Spin-1/2 Relativistic Particle in the Presence of Magnetic Field

This paper provides a study of Wigner functions for a spin-1/2 relativistic particle in the presence of magnetic field. Since the Dirac equation is described as a matrix equation, it is necessary to describe the Wigner function as a matrix function in phase space. What’s more, this function is then proved to satisfy the Dirac equation with ⋆-product. Finally, by solving the ⋆-product Dirac equation, the energy levels as well as the Wigner functions for a spin-1/2 relativistic particle in the presence of magnetic field are obtained.     

Topological Josephson Junction in Transverse Magnetic Field

JETP Letters - We consider Majorana zero modes in a Josephson junction on top of a topological insulator in transverse magnetic field. Majorana zero modes reside at periodically located nodes of...     

霍尔效应测量磁场实验的拓展

利用霍尔效应测二维空间磁场分布的拓展方案,测量了马蹄形磁铁周围的磁场分布。并用Mathematica编程对测量数据进行处理,模拟了直观形象的磁场分布图,提高了实验结果的精确度。     

Higher-Order Topological Spin Hall Effect of Sound

We theoretically propose a reconfigurable two-dimensional(2 D) hexagonal sonic crystal with higher-order topology protected by the six-fold,C₆,rotation symmetry.The acoustic band gap and band topology can be controlled by rotating the triangular scatterers in each unit cell.In the nontrivial phase,the sonic crystal realizes the topological spin Hall effect in a higher-order fashion:(i) the edge states emerging in the bulk band gap exhibit partial spin-momentum correlation and are gapp...     

Discovery of Fractionalized Neutral Spin-1/2 Excitation of Topological Order

<正>After the discovery of fraction quantum Hall states in the 1980s.~[1].it became more and more clear that Landau symmetry breaking theory does not describe all possible quantum phases of matter.The new quantum phases of matter were called topologically ordered phases~([2,3])(for gapped cases)or quantum ordered     

霍尔效应法测磁场实验误差研究

从机理上研究了霍尔效应法测定螺线管磁场实验的主要误差来源,分析了误差因素的具体特点,导出了准确的计算公式,成功消除了主要误差,研究结果表明:霍尔效应附效应产生的电势差和接触电势差以及不对称因素导致的误差均可采用对称测量法予以消除,这为霍尔效应实验教学与研究提供了更为清晰的理论参考和更为精确的测量方法。     

一种霍尔效应测量磁场的设计方法

针对大学物理实验中＂霍尔效应法测量磁场＂项目只能测长直螺线管轴线上一维稳恒磁场分布的不足,提出一种设计方法,来测量任一未知稳恒磁场的二维分布,进而可扩展到测量三维分布。可使学生深刻全面理解霍尔效应测磁场的原理及磁场的性质,并可作为设计性实验项目在大学物理实验课中开出,培养学生的创新意识。     

Effect of Bond-Diluted on Spin-3/2 Transverse Ising Model with Crystal Field

The magnetic properties of the bond-diluted spin-3/2 transverse Ising model with the presence of a crystalfield on the honeycomb lattice are studied within the framework of the effective field theory with correlations. Theinteractions Jij are assumed to be independent random variables with distribution P(Jij) ＝ pδ(Jij - J) + (1 - P)δ(Jij).     

Phase Diagram and Tricritical Behavior of a Spin-2 Transverse Ising Model in a Random Field

The phase diagrams of a spin-2 transverse Ising model with a random field on honeycomb, square, and simple-cubic lattices, respectively, are investigated within the framework of an effective-field theory with correlations.We find the behavior of the tricritical point and the reentrant phenomenon for the system with any coordination number z, when the applied random field is bimodal. The behavior of the tricritical point is also examined as a function of applied transverse field. The reentrant phenomenon comes from the competition between the transverse field and the random field.     

Thermodynamical Properties of Spin-3/2 Ising Model in a Longitudinal Random Field with Crystal Field

A theoretical study of a spin-3/2 Ising model in a longitudinal random field with crystal field is studiedby using of the effective-field theory with correlations. The phase diagrams and the behavior of the tricritical point areinvestigated numerically for the honeycomb lattice when the randorm field is bimodal. In particular, the specific heatand the internal energy are examined in detail for the system with a crystal-field constant in the critical region wherethe ground-state configuration may change from the spin-3/2 state to the spin-1/2 state. We find many interestingphenomena in the system.     

霍尔效应法测量通电双圆线圈磁场的数据处理

介绍了霍尔效应实验原理,对实验数据进行曲线拟合,得出了通电双圆线圈内磁场的分布,并计算了霍尔元件的霍尔灵敏度。     

Optical Effect in Magnetic Emulsions Induced by a Magnetic Field

Optics and Spectroscopy - Specific features of the magneto-optical effect of a change in the transparency of a magnetic emulsion with low interfacial tension have been investigated. The effect has...     

Discrete Energy Spectrum for a Spin-1/2 Quantum Particle Under the Influence of a Constant Force Field due to the Presence of Topological Defects

We study a spin-1/2 quantum particle under a constant force field in the presence of a uniform distribution of parallel screw dislocations. We solve the Schröndiger equation, exactly, and find a discrete energy spectrum.