Finite temperature transition in lattice QCD with the strange quark

我们研究了量子色动力学（QCD）有限温度相变的性质，使用晶格形式，这使得我们能够与超级计算机的非微扰调查。我们采用威尔逊费米子来表示夸克。(1)在标准格点作用量下，研究了2、3、6味简并夸克以及无质量上、下夸克和轻奇异夸克的有限温度跃迁性质.我们的模拟表明，在手征极限的有限温度转变是连续的两个口味，而它是一阶的3和6口味。我们发现，对于无质量的上夸克、下夸克和物理奇夸克，跃迁是一级跃迁。这一结果与以前的交错夸克的结果不同。由于在现有的两种晶格上的研究都偏离了连续极限，因此需要用更大的晶格或改进的作用量进行计算，以便得到连续极限。 ...更多信息 对QCD跃迁的性质给出了明确的结论。(2)用重整化群改进的规范作用量和Wilson夸克作用量研究了含两个简并轻夸克的QCD的有限温度跃迁。结果表明，手征凝聚体与三维O（4）Heisenberg模型的指数显著地满足标度关系。这表明在连续极限下，双味QCD中的手征跃迁是二阶的。(3)我们还研究了从2到300味的QCD的零温相结构。基于数值结果我们提出了如下的结论：当N_F为17时<greater than or equal>，只有一个平凡不动点，因此在连续极限下的理论是平凡的。另一方面，当<greater than or equal>16NF7<greater than or equal>时，存在一个非平凡的不动点，因此在反常维数下理论是非平凡的，然而，没有夸克禁闭。同时满足夸克禁闭和手征对称性自发破缺的理论只存在于N_F &lt;小于小于

We study the nature of the finite temperature phase transition of Quantum Chromodynamics (QCD) using the lattice formalism, which allows us nonperturbative investigations with supercomputers. We adopt Wilson fermions for quarks.(1) With the standard lattice action, the nature of finite temperature transitions is studied for the cases of 2,3, and 6 flavors of degenerate quarks and also for the case of massless up and down quarks and a light strange quark. Our simulations indicate that the finite temperature transition in the chiral limit is continuous for two flavors, while it is of first order for 3 and 6 flavors. We find that the transition is of first order for the case of massless up and down quarks and the physical strange quark. This result is different from the previous result with staggered quarks. Since the deviation from the continuum limit is large in both studies on present lattices, a calculation with larger lattice or with an improved action would be needed in order to obt … More ain a definite conclusion about the nature of the QCD transition.(2) The finite temperature transition of QCD with two degenerate light quarks is studied with a renormalization group improved gauge action and the Wilson quark action. It is shown that the chiral condensate satisfies remarkably a scaling relation with the exponents of the three dimensional O (4) Heisenberg model. This indicates that the chiral transition in two-flavor QCD is of second order in the continuum limit.(3) We also investigate the zero temperature phase structure of QCD for flavors from 2 up to 300. Based on numerical results we propose the following picture : When N_F <greater than or equal> 17, there is only a trivial fixed point and therefore the theory in the continuum limit is trivial. On the other hand, when 16 <greater than or equal> N_F <greater than or equal> 7, there is a non-trivial fixed point and therefore the theory is non-trivial with anomalous dimensions, however, without quark confinement. Theories which satisfy both quark confinement and spontaneous chiral symmetry breaking in the continuum limit exist only for N_F <less than Less