格点量子色动力学在中国

1.格点量子色动力学概述经过多年努力,人们已经成功地将自然界四种基本相互作用(强、弱、电磁、引力)中的前三种统一在量子场论的框架之中,即粒子物理的标准模型(Standard Model,SM)。     

多个含不同质量项的费米子矩阵求逆算法

在格点量子色动力学的模拟中,Rational Hybrid Monte Carlo (RHMC)算法是一种精确的,能应用到任意多个味道数的费米子的方法.它的思想是把费米子行列式展开为有理函数的形式.但该方法会带来很多彼此相差一个常对角矩阵的矩阵的求逆的计算,消耗大量的时间和计算资源,限制了RHMC算法的应用.本文利用移位多项式,针对共轭梯度法得到多个含有不同质量项的矩阵求逆的一种方法,该方法可以应用到RHMC算法中.     

Transition Temperature of Lattice Quantum Chromodynamics with Two Flavors with a Small Chemical Potential

We present the results for the transition temperature of quantum chromodynamics with two degenerate flavors （Nf=2） of Wilson quarks as a function of a small baryon chemical potential μB from Monte Carlo simulations at κ=0.175, κ is the hopping parameter. By using the imaginary chemical potential for which the fermion determinant is positive and the Ferrenberg-Swendsen reweighting method, we perform simulations on lattice 83×4 with 4 being the temporal extent. By analytic continuation of the data to the real chemical potential μ, we obtain the transition temperature for the small chemical potential, and compare our results with others.     

Be~(2 )等二电子系列基态关联能计算方法的研究

在组态相互作用模型的基础上对Ｂｅ２＋等二电子系列基态电子关联能的计算方法进行了研究，利用变分原理，采用Ｂ样条处理径向基，用“混合Ｌ”法处理角向基，给出Ｈｅ，Ｈ－，Ｌｉ＋，Ｂｅ２＋，Ｂ３＋等５种原子（离子）系列的有关计算结果，并与其它理论方法计算的结果作了对比，显示出Ｂ样条方法优越的计算能力．     

Transition Temperature of Two-Degenerate-Flavour QCD in the Chiral Limit

We present the results for the transition temperature of quantum chromodynamics （QCD） with two degenerate flavours （Nf = 2） of Wilson quarks. On lattice 8^3 × 4 with 4 representing the temporal extent, by using the Ferrenberg-Swendsen reweighting method, we determine the critical β = 6/g^2 where the transition occurs, g is the coupling constant. On lattice 8^2 × 20 × 4, by using the axial vector Ward-Takahashi identity, we calculate the current quark mass amq, a is the lattice spacing. Assuming the O（4） scaling, the critical β in the chiral limit is determined. We calculate the p meson mass amp at zero temperature on lattice 8^3 × 20. By using the experimental p meson mass to set the scale, we obtain 194（1） MeV for the transition temperature in the chiral limit.