Lattice gauge Theory with Numerical Method

用作者在1984-1985年发展的朗之万法进行了全QCD(量子色动力学)模拟，主要结果是：(1)当夸克与系统耦合时，纯规范理论的一阶解禁闭相变减弱。然而，当夸克质量减小时，一级相变恢复为手征相变，这在两个时间点引起了夸克的解放。(2)夸克场的动力学自由度的影响很大程度上改变了强子质量，使其晶格消失。然而，随着理论初始参数的改变，这种影响被重新吸收，并且物理结果与淬灭近似下得到的结果没有不同，在猝灭近似下，夸克场对规范场的影响被关闭。这是在淬灭近似下强子质量计算成功的基础。

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.