用于教学的万有引力常数测定仪——HG引力仪的研制

测Ｇ的方法主要有两种：一是扭摆法；二是扭秤法即Ｃａｖｅｎｄｉｓｈ方法．作为教学目的，测量Ｇ值主要用扭秤方法．ＨＧ引力仪可用扭秤方法，但主要采取扭摆方法来测定Ｇ值，前者的精度在１０％以内，后者的精度更高，达到了５％．另外，该仪器能做检测万有引力定律实验．     

用原子束干涉法测定引力常量G

引力常量G是一个重要的普适常量，自从1798年英国物理学家卡文迪什（H．Cavendish）用扭秤第一次精确地测定了G以来，200年间，很多实验工作者对G进行测量所用的方法大体上都是在扭秤法基础上的改进，测量精度几乎仍停留在三位有效数字．     

利用扭秤检验牛顿反平方定律在近距离范围的正确性

许多理论模型预言牛顿引力反平方定律在近距离下将发生偏离.本文简要介绍了牛顿反平方定律的实验检验现状,给出了利用精密扭秤技术检验近距离反平方定律的实验原理和实验结果,分析了扭秤实验的热噪声和灵敏度.     

用于教学的万有引力常数测定仪—HG引力仪的研制

测Ｇ的方法主要有两种；一是扭摆法：二是扭秤法即Ｃａｖｅｎｄｉｓｈ方法。作为教学目的，测量Ｇ值主要用扭秤方法，ＨＧ引力仪可用扭秤方法，但主要采取扭摆方法来测定Ｇ值，前者的精度在１０％以内，后者的精度更高，达到了５％，另外，该仪器能做检测万有引力定律实验。     

利用精密扭秤测量微小电量

充分利用精密扭秤对弱力的高灵敏度,结合机械共振放大力的效应原理、电磁阻尼原理和光杠杆原理进行改装,可测得带电体所受的弱电场力,进而求得微小电量。初步实验结果证实该方法的可行性。     

简易库仑扭秤的制作和应用

库仑扭秤是定量反映静电力和电荷量以及点电荷之间距离关系实验装置,在中学实验室中很难见到.和卡文迪什扭秤一样,扭秤可以体现两种思想,一是通过力矩放大力的作用效果,另一种是通过平面镜放大测量效果,是物理学中重要的思想方法.尽管有些实验室没有扭秤,但我们可以设计简易扭秤让学生体验该思想方法.     

一类非线性动力系统的稳定性及周期运动

根据“库仑扭秤”实验的原理提出了一个非线性动力系统模型,分析了其稳定性及其周期运动．     

对扭秤法测万有引力常数实验的探讨

对扭秤法测万有引力常数实验中的隔振和求平衡点两个重要问题进行了论述．     

基于扭秤的激光干涉差动测量微小冲量方法

基于扭秤测量冲量原理,结合激光干涉法差动测量角度的方法,提出一种基于扭秤的激光干涉差动测量微小冲量的方法。介绍系统的基本组成和测量过程,给出扭秤结构设计参数,并对系统参数进行了标定,结合设计参数与标定结果,对系统的分辨率、量程和精度进行了校核,在典型的测量环境下,对激光烧蚀靶材所形成的Ns量级微小冲量进行了测量,给出了典型的测量结果并进行分析。结果表明:所提出的基于扭秤的激光干涉差动测量微小冲量方法,系统分辨率可达10-7Ns量级,测量范围跨5个数量级,最大可以测量10-2Ns量级冲量,测量精度优于95%。     

“库仑扭秤”与“卡文迪什扭秤”实验

详细回顾了库仑扭秤与卡文迪什扭秤实验的科学背景和实验经历,并对其背后的历史渊源和物理意义进行总结.     

激光干涉法测引力常量

在扭摆法测量引力常量的基础上,提出利用激光干涉法测扭转偏角,并采用磁感应力来消减周围环境的噪声干扰,能使引力常量G的测量精度有很大提高.     

Spin connection resonance in magnetic motors

A mechanism is proposed for rotation of magnetic assemblies by a torque consisting of the magnetic dipole moment of the assembly and a magnetic field generated from space–time in Einstein–Cartan–Evans (ECE) field theory. It is shown that when the magnetic assembly is stationary, the space–time is described by a Helmholtz wave equation in the tetrad as eigenfunction. This is a balance condition in which the Cartan torsion of the space–time is zero, but in which the tetrad and spin connection are non-zero. This balance may be broken by a driving current density produced by the magnetic assembly. The Helmholtz equation becomes an undamped oscillator equation. At resonance the torque on the magnetic assembly may be amplified sufficiently to cause the whole assembly to rotate, as observed experimentally in a repeatable and reproducible manner.     

Further Support of the Reliability of the Limit on Photon Mass Given by the Rotating Torsion Balance Experiment

We consider there is a vacancy in the plasma in the solar system,and calculate the vector potential produced by the magnetic field frozen in the plasma.The result shows that,in the vacancy,the vector potential produced by the magnetic field frozen in the plasma is much less than the large scale cosmic vector potential.This means if our earth is in such a vacancy,the total vector potential on the surface of the earth is dominated by the cosmic magnetic vector potential,which gives a further support of the reliability of the limit on photon mass given by rotating torsion balance experiment [Phys.Rev.Lett.90(2003) 081801].     

Further Support of the Reliability of the Limit on Photon Mass Given by the Rotating Torsion Balance Experiment

We consider there is a vacancy in the plasma in the solar system, and calculate the vector potential produced by the magnetic field frozen in the plasma. The result shows that, in the vacancy, the vector potential produced by the magnetic field frozen in the plasma is much less than the large scale cosmic vector potential. This means if our earth is in such a vacancy, the total vector potential on the surface of the earth is dominated by the cosmic magnetic vector potential, which gives a further support of the reliability of the limit on photon mass given by rotating torsion balance experiment [Phys. Rev. Lett. 90 (2003) 081801].     

Emergent geometry experienced by fermions in graphene in the presence of dislocations

In graphene in the presence of strain the elasticity theory metric naturally appears. However, this is not the one experienced by fermionic quasiparticles. Fermions propagate in curved space, whose metric is defined by expansion of the effective Hamiltonian near the topologically protected Fermi point. We discuss relation between both types of metric for different parametrizations of graphene surface. Next, we extend our consideration to the case, when the dislocations are present. We consider the situation, when the deformation is described by elasticity theory and calculate both torsion and emergent magnetic field carried by the dislocation. The dislocation carries singular torsion in addition to the quantized flux of emergent magnetic field. Both may be observed in the scattering of quasiparticles on the dislocation. Emergent magnetic field flux manifests itself in the Aharonov–Bohm effect while the torsion singularity results in Stodolsky effect.     

On possible light–torsion mixing in background magnetic field

The interaction of the light with propagating axial torsion fields in the presence of an external magnetic field has been investigated. Axial torsion fields appearing in higher derivative quantum gravity possess two states, with spin one and zero, with different masses. The torsion field with spin-0 state is a ghost that can be removed if its mass is infinite. We investigate the possibility when the light mixes with the torsion fields resulting in the effect of vacuum birefringence and dichroism. The expressions for ellipticity and the rotation of light polarization axis depending on the coupling constant and the external magnetic field have been obtained.     

Torsion effects on condensed matter: like a magnetic field but not so much

In this work, we study the effects of torsion due to a uniform distribution of topological defects (screw dislocations) on free spin/carrier dynamics in elastic solids. When a particle moves in such a medium, the effect of the torsion associated to the defect distribution is analogous to that of an applied magnetic field but with subtle differences. Analogue Landau levels are present in this system but they cannot be confined to two dimensions. In the case of spinless carriers, zero modes, which do not appear in the magnetic Landau levels, show up for quantized values of the linear momentum projected on the defects axis. Particles with spin are subjected to a Zeeman-like coupling between spin and torsion, which is insensitive to charge. This suggests the possibility of spin resonance experiments without a magnetic field for charged carriers or quasiparticles without electrical charge, like triplet excitons, for instance.     

Torsional Weyl-Dirac Electrodynamics

Issuing from a geometry with nonmetricity and torsion we build up a generalized classical electrodynamics. This geometrically founded theory is coordinate covariant, as well as gauge covariant in the Weyl sense. Photons having arbitrary mass, intrinsic magnetic currents, (magnetic monopoles), and electric currents exist in this framework. The field equations, and the equations of motion of charged (either electrically or magnetically) particles are derived from an action principle. It is shown that the interaction between magnetic monopoles is transmitted by massive photons. On the other hand, the photon is massive only in the presence of magnetic currents. We obtained a static spherically symmetric solution, describing either the Reissner-Nordstrom metric of an electric monopole, or the metric and field of a magnetic monopole. The latter must be massive. In the absence of torsion and in the Einstein gauge one obtains the Einstein-Maxwell theory.     

Measurement of Magnetic Properties of an Inertial Sensor with a Torsion Balance

A torsion balance is constructed to accurately measure the magnetic properties of the real proof mass of the inertial sensor. The magnetic susceptibility and remnant moment of a titanium proof mass are measured in the first experiment, and further improvements and the potential sensitivity are also discussed. This is significant for choosing the material of the proof mass and investigating the magnetic disturbances acting on the proof mass.     

REVIEW: Spin Gravity

A theory of gravitation with torsion that isderived from an antisymmetric second rank tensor isreviewed. A non-symmetric energy momentum tensor isdeveloped and the explicit material action is presented. This is done from a phenomenological point ofview and using the Dirac Lagrangian. The equations ofmotion are derived and it is shown that the source oftorsion is the intrinsic spin of elementary particles. The torsion sector is reduced to a low energy3-vector formulation and the interaction energies arederived. The theory is reformulated in terms of theDirac field, and it is shown that precisely the same interaction energy is predicted. The theory iscompared to the low energy string theory effective fieldlimit and the scalar field is introduced. It is shownhow this field is a mandatory requirement of the theory, and a particular limit is derivedin which the scalar field acts as a strong non-minimalcoupling of the torsion field. Physical predictions arecompared to experiment, including effects in hydrogen and paramagnetic salts. Other physicalmanifestations that are discussed include spin flippingof neutrinos, torsion waves and their power, how thenon-linear Dirac and Schrodinger equations arise from torsion, and the physical origin andcorrect prediction of the magnetic dipole moment ofelementary particles.