International collaboration on the vacuum structure of full QCD using large-scale parallel computers

主要通过使用KEK的SR8000和RIKEN的SX7进行蒙特卡罗模拟研究获得以下结果：(1)DIK小组有限温度全QCD研究：与DESY和ITEP小组的国际合作。相变温度是在16^3X8和24^3X10晶格上用Nf=2轻夸克的0（α）改进三叶草费米子作用确定的。利用前人在Nt=4和Mt=6时的数据，我们首次获得了手性极限和连续体极限下的相变温度，尽管所用的夸克质量不够轻。我们正在继续用KEK的新蓝基因机器在更轻的夸克质量下进行模拟。(2)约束机制的规范不变性：约束是一种物理现象，因此必须有一个规范不变性机制来解释约束。迄今为止，利用非局域尺度的阿贝尔投影方法可以很好地将约束解释为双迈斯纳效应。使用理化学研究所的SX7并进行广泛的蒙特卡罗模拟，我们发现即使在朗道规范中，阿贝尔对偶迈斯纳效应也能很好地工作。然而，在规范中，没有阿贝尔单极子，而是磁位移电流挤压电场。这种情况预计在一般情况下是可行的，因此我们正在用不同的本地测量仪（称为坏测量仪）进行模拟，以检查期望。

The following results have been obtained mainly from Monte-Carlo simulation studies using SR8000 at KEK and SX7 at RIKEN :(1)DIK group study of finite-tenperature full QCD :International collaboration with DESY and ITEP groups. The phase transition temperature is determined on lattices of 16^3X8 and 24^3X10 using an 0(alpha) improved clover fermion action with Nf=2 light quarks. Using the previos data at Nt=4 and Mt=6,we have obtained for the first time the phase transition temperature in the chiral and the continuum limits, although the quark mass used is not light enough. We are continuing the simulations at lighter quark masses using a new BlueGene maschine at KEK.(2)Gauge invariance of the confinement mechanism :Confinement is a physical phenomenon and so there must be a gauge-invariant mechanism explaining confinement. Up to now abelian projection methods using some non-local gauges can explain the confinement beautifully as the dual Meissner effect.Using SX7 at Riken and performing an extensive Monte-Carlo simulations, we have found even in Landau gauge, the abelian dual Meissner effect works good. However in the gauge, there are no abelian monopoles, but instead the magnetic displacement currents squeezes the electric field.This kind of picture is expected to work in general and so we are doing simulations in various local gauges (known as a bad gauge) to check the expectation.