Dynamics of the quark-gluon plasma and high density hadronic matter

本文利用最大熵法在欧几里得晶格上测量的相关函数，构造了由粲夸克对和反粲夸克对组成的矢量（J/ψ）和轴向矢量（η_c）通道在有限温度下的谱函数，并首次系统地应用于晶格规范理论。结果表明，在远高于QCD相变温度（约1.6T_c）的温度范围内，这两种状态继续存在，并在1.6T_c至1.7T_c之间的一个非常窄的温度区域内消失。这表明夸克-胶子等离子体不是夸克和胶子几乎自由运动的状态，而是强子激励共存的强耦合系统本文根据相变理论中的普适假设，推导出具有临界终点的一般状态方程，并发现临界终点在系统的时间演化过程中起着吸引子的作用。此外，我们还首次讨论了高能重离子碰撞产生的系统在时间演化过程中经过临界终点附近时的涨落和相关长度的时间演化，以及它们在统一框架下对观测值的影响。

1 We have constructed the spectral functions at finite temperature for the vector (J/ψ) and axial-vector (η_c) channels made of a charm and anti-charm quark pair from their correlation functions measured on the Euclidean lattices with the maximum entropy method, which was applied systematically to lattice gauge theory for the first time by our group. It was shown that both states continue to exist up to a temperature that is much higher than the QCD phase transition temperature, that is, about 1.6T_c and that they both disappears in a very narrow temperature region, between about 1.6T_c and 1.7T_c This suggests that the quark-gluon plasma is not a state where quarks and gluons are almost freely moving as usually believed, but that it is a strongly coupled system where also hadronic excitations coexists.2 It has been argued that there is possibly a critical end point on the QCD phase diagram, where the order of the phase transition changes from first to crossover We have derived general equations of states with a critical end point on the basis of the universality hypothesis in phase transition theory and found that it acts as an attractor in the course of the time evolution of the system. Furthermore, we discussed for the first time the time evolution of fluctuations and correlation lengths when the system created in high energy heavy ion collisions pass the proximity of the critical end point in the course of its time evolution and their effects on observables in a unified framework.