Holographic Schwinger effect in an anisotropic background with Gauss-Bonnet corrections

Using the anti-de Sitter/conformal field theory(AdS/CFT) correspondence,we study the holographic Schwinger effect in an anisotropic background with the Gauss-Bonnet term.As the background geometry is anisotropic,we consider both cases of the test particle pair and the electric field perpendicular to and parallel to the anisotropic direction.It is shown that the Schwinger effect is enhanced in the perpendicular case when anisotropy rises.In the parallel case,this effect is reversed.Additionally,t...     

ρ介子质量对温度和化学势的依赖性

考虑到真空效应,用有效拉氏量方法给出了介质对ρ介子质量的影响,发现ρ介子质量随温度和化学势的升高而降低.然后用所得到的结果检验了Brown-Rho标度定理的适用范围.     

Shear and bulk viscosity of high-temperature gluon plasma

We calculate the shear viscosity(η) and bulk viscosity(ζ) to entropy density(s) ratios η/s and ζ/s of a gluon plasma system in kinetic theory, including both the elastic gg?gg forward scattering and the inelastic soft gluon bremsstrahlung gg?ggg processes. Due to the suppressed contribution to η and ζ in the gg?gg forward scattering and the effective g?gg gluon splitting, Arnold, Moore and Yaffe(AMY) and Arnold, Dogan and Moore(ADM) have got the leading order computations for η and ζ in high-temperature QCD matter. In this paper, we calculate the correction to η and ζ in the soft gluon bremsstrahlung gg?ggg process with an analytic method.We find that the contribution of the collision term from the gg?ggg soft gluon bremsstrahlung process is just a small perturbation to the gg?gg scattering process and that the correction is at～ 5% level. Then, we obtain the bulk viscosity of the gluon plasma for the number-changing process. Furthermore, our leading-order result for bulk viscosity is the formula ζ∝(α_s~2 T~3)/(lnα_s~(-1)) in high-temperature gluon plasma.     

QGP中快速粒子衰减率的自洽研究

采用实时有限温度QCD形式,提出了QGP中快速运动粒子的衰减率的自治求解方法,克服了通常计算中红外发散的困难,不需要手加进磁质量作为红外截断.当耦合常数很小时,给出了横胶子和夸克的衰减率,并估计了它们在RHIC和LHC实验中的弛豫时间.     

φ36的媒质效应和热不稳定性

在有限温度下运用硬热圈近似求得φ36理论单圈自能,进而求得有限质量和衰变率. 发现在临界温度Tc以上存在热不稳定性,而有效温度和衰变率则分别正比于gT和gT. 最后将所得结果与热QCD比较.     

任意规范下有限温度二圈QED热力学势及其交叉发散

采用有限温度下维数正规化的方法在任意协变规范下精确地计算了双圈ＱＥＤ的热力学势及其交叉发散．计算表明交叉发散彼此相消且所得的结果与规范的选取无关．     

两味LOFF态下的色超导

自从色超导理论被提出以来, 通常考虑的是参与配对的夸克的化学势不相等时的情形。 当化学势的差别达到某一合适值时, 库柏对就有非零的总动量, 这就是Larkin Ovchinnikov Fulde Ferre(LOFF)态。 这种形式的夸克凝聚自发破坏了平移不变性和旋转不变性, 导致能隙以晶格的形式周期性变化。 在中等重子数密度区的基础上, 从SU（2） NJL模型出发描述两味LOFF态, 并通过平均场近似, 引用N G基底、 傅立叶变换和频率求和等方法得到热力学势, 进而通过热力学势对序参量求偏导得到耦合的Gap方程, 并使用数值法解耦合方程找到LOFF态的窗口。 Ever since the theory of color superconductivity was issued, it is likely to involve pairing between species of quarks with differing chemical potentials. For suitable values of the differences between chemical potentials, Cooper pairs with non zero total momentum are favored, as was first realized by Larkin, Ovchinnikov, Fulde and Ferrell (LOFF). Condensates of this sort spontaneously break translational and rotational invariance, leading to gaps which vary periodically in a crystalline pattern. This article focuses on the two flavor color superconducting phase at moderate baryon density. LOFF state is described through SU(2) NJL model. By using the mean field approximation, N G basis, fourier transformation, frequency summation, the thermodynamic potential and Gap equation are obtained. Finally, the window of LOFF state is found by the numerical method.     

ψ6^3的媒质效应和热不稳定性

在有限温度下运用硬热圈近似求得ψ6^3理论单圈自能，进而求得有限质量和衰变率。发现在临界温度Tc以上存在热不稳定性，而有效温度和衰变率则分别正比于√gT和gT。最后将所得结果与热QCD比较。