Lattice gauge Theory with Numerical Method

利用本研究者在1984 - 1985年开发的Langevin方法进行了全QCD（量子色动力学）模拟，主要结果是：(1)当夸克耦合到系统中时，纯规范理论的一阶定义相变减弱。然而，当夸克的质量减小时，一阶相变恢复为手性相变，并在两段时间内引起夸克的解放。(2)夸克场的动态自由度的影响在很大程度上改变了晶格外离的强子质量。然而，这种效应随着理论初始参数的移动而被重新吸收，并且物理结果与用淬灭近似得到的结果没有区别，在淬灭近似中，夸克场对规范场的影响被关闭。这是强子质量计算在淬灭近似中取得成功的基础。

Full QCD (quantum chromodynamics) simulation was carried out using the Langevin method developed by the present investigator in 1984 - 1985 with the main result that:(1) The first-order deconfining phase transition of pure gauge theory weakens when quarks are coupled to the system. When the mass of quark decreases, however, a first-order phase transition recovers as a chiral phase transition, which at two sauce time causes the quark liberation.(2) The effect of dynamical degrees of freedom of quark fields largely modifies hadron masses with a lattice out-off. The effect however, is reabsorbed with the shift of initial parameters of the theory and the physical result does not differ from the one obtained with quenched approximation, where the effect of quark fields to gauge fields are switched off. This underlies the success of hadron mass calculation in the quenched approximation.