产生在夸克–胶子等离子体中的中等质量双轻子的增强

基于一个相对论流体力学模型,在夸克–胶子等离子体中具有中等质量双轻子的产生被研究.由于相边对夸克–胶子等离子体系统演化的影响和产生在RHIC能量的夸克–胶子等离子体系统有高的初始温度,夸克相的贡献变得比强子相互作用的贡献重要得多,甚至能与本底相比较.它表明这样的增强是夸克–胶子等离子体形成的一种信号.     

X射线在金属表面产生Compton电流引起的电磁辐射时空分布

 研究了强X射线在金属表面产生的Compton电流时空分布,利用Compton散射公式计算了出射电子动量和微分散射截面随电子出射角的变化关系,发现在光子能量为1 MeV、入射光强为10²¹ W·m^-2的条件下,沿入射光方向形成的Compton电流密度达到10⁷ A·m^-2量级。采用1维电动力学模型计算了斜入射的X射线在金属表面产生的Compton电流密度引起的电磁脉冲,结果表明：X射线在单位长度金属辐射产生的磁场强度达到106 A·m^-1量级,脉冲宽度为ps量级;电磁脉冲沿X射线反射方向传播,具有良好的定向性。     

QGP tomography with photon tagged jets in ALICE

γ+jet events provide a tomographic measurement of the medium formed in heavy ion collisions at LHC energies.Tagging events with a well identified high p T direct photon and measuring the correlation distribution of hadrons emitted oppositely to the photon in ALICE,allows us to determine,with a good approximation,both the jet fragmentation function and the back-to-back azimuthal alignment of the direct photon and the jet.Comparing these two observables measured in pp collisions with the ones measured in AA collisions will reveal the modifications of the jet structure induced by the medium formed in AA collisions and consequently will infer the medium properties.     

QGP tomography with photon tagged jets in ALICE

γ＋jet events provide a tomographic measurement of the medium formed in heavy ion collisions at LHC energies.Tagging events with a well identified high p T direct photon and measuring the correlation distribution of hadrons emitted oppositely to the photon in ALICE,allows us to determine,with a good approximation,both the jet fragmentation function and the back-to-back azimuthal alignment of the direct photon and the jet.Comparing these two observables measured in pp collisions with the ones measured in AA collisions will reveal the modifications of the jet structure induced by the medium formed in AA collisions and consequently will infer the medium properties.     

X射线在金属表面产生Compton电流引起的电磁辐射时空分布

研究了强X射线在金属表面产生的Compton电流时空分布,利用Compton散射公式计算了出射电子动量和微分散射截面随电子出射角的变化关系,发现在光子能量为1 MeV、入射光强为1021 W·m-2的条件下,沿入射光方向形成的Compton电流密度达到107 A·m-2量级。采用1维电动力学模型计算了斜入射的X射线在金属表面产生的Compton电流密度引起的电磁脉冲,结果表明：X射线在单位长度金属辐射产生的磁场强度达到106 A·m-1量级,脉冲宽度为ps量级;电磁脉冲沿X射线反射方向传播,具有良好的定向性。     

The nonlinear spatial damping rate in QGP

The derivative expansion method has been used to solve the semiclassical kinetic equations of quark-gluon plasma. The nonlinear spatial damping rate, the imaginary part of the wave vector, for the longitudinal secondary color waves in the long wavelength limit has been calculated numerically.     

QGP中夸克静色电波的辐射研究

利用QGP中存在德拜屏蔽现象以及高温极限下QGP中夸克的分布函数和色电势,得到QGP中夸克静色电波的辐射功率. 讨论了夸克静色电波的辐射功率与德拜长度λ_D的关系,有助于利用辐射功率研究德拜屏蔽位势.     

A numerical study of SU(3) charge-two monopoles with minimal symmetry breaking

Charge-two SU(3) monopoles with minimal symmetry breaking can be generated via Nahm's equations. This paper investigates the detailed structure of such monopoles, through explicit calculation of the energy density, and the norm and discriminant of the Higgs field. Monopoles may be classified according to the maxima and minima of these quantities.     

Semiclassical Quasilinear Equation of Turbulent QGP and Non-Abelian Quasilinear Diffusion

After the concept of turbulent QGP is introduced, the quasilinear equations for turbulent QGP are given. Starting from the field equation, we still treat the collective modes as plasmons that satisfy a transport equation. Using the quasilinear equations for quarks and gluons and the transport equation for plasmons, the collisionless diffusion is discussed. We obtain the quasilinear drag coefficient and the diffusion coefficient.     

在近平衡态QGP中费米子的分布函数

从QGP动力论出发,得到QGP在色场涨落扰动下偏离平衡态而处于近平衡时的分布函数, 进而分析了决定偏离因子的物理因素.并分别讨论了在高温低密和低温高密区偏离因子特征.     

分析QGP相变级次的一种可能方法

在推广的Ginzburg-Landau理论框架内,解析地研究了在QGP转化为强子的相变过程中多重数差关联矩F_q与相空间间隔δ的依赖关系,提出了一种在实验中判断QGP相变级次的可能方法.此方法的特点在于它不依赖系统温度这个未知的参量,对于低维和高维的实验数据均可以得出相同的相变信息.     

Mechanism of crossover between hadron gas and QGP and the liquid property of sQGP

We raise for the first time the highly important question that the hadronization of partons one by one as assumed in current models for crossover in QCD, contradicts color confinement. A possible mechanism — molecule-like hadron aggregation — is proposed for crossover compatible with color confinement. A toy model to realize this mechanism is constructed. A kind of grape-shape quark gluon plasma (gQGP) is obtained. Pair distribution function for gQGP is calculated which exhibits the character of liquid.     

关于QGP中夸克屏蔽位势来自动力论方程的研究

从ＱＧＰ的动力论方程出发，计及运动检验夸克的色电场扰动，采用微扰方法，并在高温极限下得到ＱＧＰ中夸克的分布函数和色电势．给出了考虑运动效应在内的德拜长度λＤ（或屏蔽质量ωＤ）与温度Ｔ的关系，在静态极限下它们与ＱＣＤ理论相符．     

Electromagnetic wormholes and virtual magnetic monopoles from metamaterials

We describe new configurations of electromagnetic (EM) material parameters, the electric permittivity epsilon and magnetic permeability micro, which allow one to construct devices that function as invisible tunnels. These allow EM wave propagation between the regions at the two ends of a tunnel, but the tunnels themselves and the regions they enclose are not detectable to lateral EM observations. Such devices act as wormholes with respect to Maxwell's equations and effectively change the topology of space vis-à-vis EM wave propagation. We suggest several applications, including devices behaving as virtual magnetic monopoles, invisible cables, and scopes for MRI-assisted surgery.     

Z箍缩等离子体振荡引起的电磁脉冲辐射

从理论上研究了Z箍缩过程中单模的等离子体振荡引起的电磁脉冲辐射。当模式扰动的相速度大于真空中的光速时,电磁脉冲辐射具有类似于切伦科夫辐射的角分布特征,并且随着相速度的增大这种定向辐射特征越显著;不同波长的电磁辐射也具有不同的角分布特征,短波长的电磁脉冲具有更好的定向性。电磁辐射功率强烈依赖于电子的等离子体振荡频率和等离子体柱的半径。     

Z箍缩等离子体振荡引起的电磁脉冲辐射

从理论上研究了Z箍缩过程中单模的等离子体振荡引起的电磁脉冲辐射。当模式扰动的相速度大于真空中的光速时,电磁脉冲辐射具有类似于切伦科夫辐射的角分布特征,并且随着相速度的增大这种定向辐射特征越显著;不同波长的电磁辐射也具有不同的角分布特征,短波长的电磁脉冲具有更好的定向性。电磁辐射功率强烈依赖于电子的等离子体振荡频率和等离子体柱的半径。     

158A GeV/c Pb+Pb碰撞可能有QGP的一旁证

用不含QGP假设的强子和弦级联模型(JPCIAE) ,研究了CERNWA98实验组新近发表的158 AGeV/c Pb+Pb中心碰撞中直接光子和π⁰粒子的横动量分布:两者的理论结果均一致的低于实验值.联系到JPCIAE能成功解释无直接光子超出确切迹象的WA80和WA93对200A GeV/c S+Au中心碰撞测量得出的结果:因而为158A GeV/c Pb+Pb中心碰撞中可能有QGP生成提供了一个旁证.     

Electromagnetic radiation in a semi-compact space

In this note, we investigate the electromagnetic radiation emitted from a revolving point charge in a compact space. If the point charge is circulating with an angular frequency ${\omega }_0$ on the $(x,y)$-plane at $z=0$ with boundary conditions, $x～x+2\pi R$ and $y～y+2\pi R$, it emits radiation into the z-direction of $z\in [?\infty ,+\infty ]$. We find that the radiation shows discontinuities as a function of ${\omega }_{0}R$ at which a new propagating mode with a different Fourier component appears. For a small radius limit ${\omega }_{0}R?1$, all the Fourier modes except the zero mode on $(x,y)$-plane are killed, but an effect of squeezing the electric field totally enhances the radiation. In the large volume limit ${\omega }_{0}R\to \infty$, the energy flux of the radiation reduces to the expected Larmor formula.     

低频电磁辐射与脑神经细胞微管的相互作用

研究了低频电磁辐射场与脑神经系统的相互作用规律及其机理。电磁辐射为非电离低频电磁场, 将脑神经细胞骨架微管（MT）中的两态物理系统进行量子化,用密度矩阵描述脑神经系统中信息位的状态, 建立并求解脑神经系统中信息位的动力学方程。 结果表明: 当非电离低频电磁辐射射向大脑时, 脑神经系统中信息位的密度矩阵非对角元在任意时刻都不为零, 能够保持较好的量子相干性, 脑神经系统的功能不会受到破坏。     

Strength of a Magnetically Permeable Surface Layer on Transient Electromagnetic Field by Using Natural-frequency Concept

The complete time-domain fields due to a vertical magnetic dipole on the surface of two-layer earth model are reexamined when the usually neglected magnetic permeability contrast is considered using the natural-frequency concept. It is shown that for two-layered earth model, where the upper one is permeable, the electromagnetic induction response is modified with respect to the nonpermeable case. The step responses of the induced voltage in a horizontal receiving loop is found to have definite diagnostic features for the ground beneath. These features have been demonstrated by numerical results and illustrated by figures.