Study of nonperturbative correlations inthe quark gluon plasma

众所周知，假设零粘度的流体力学计算可以相当好地解释RHIC的观测结果。在RHIC，人们也知道，热化是出乎意料的快。这可以用维贝尔不稳定性引起和放大的色磁场使部分子热化的机制来解释。我们提出了一种统一解释这两者的机制。也就是说，由色磁场引起的部分的异常输运优于通常的两体碰撞输运，从而使系统表现得像一个理想场。由这种机制引起的粘度是反常的，因为它作为剪切的函数不是恒定的，而是降低的最近有两组研究人员通过测量原点处能量动量张量谱函数的斜率，测量了平衡状态下的剪切粘度和体粘度。他们用晶格规范理论计算谱函数。然而，由于从晶格上的虚时间计算到实时计算的解析延延，仍然存在一些困难，因此尚不能确定夸克-胶子等离子体的剪切粘度值是否接近AdS/CFT对应中预测的值，或者在相变附近体粘度是否增加。为了克服这些困难，我们开发了一种不需要解析延拓的计算黏度的新方法，并对该方法进行了初步研究。

1 It has been known that hydrodynamical calculations which assume zero viscosities can explain observables at RHIC reasonably well. At RHIC, it has been also known that thermalization is unexpectedly fast. This has been explained by a mechanism in which color magnetic field caused and amplified by Weibel instability thermalizes partons. We proposed a mechanism that these two are explained in a unified way. Namely, the anomalous transport of partons caused by this color magnetic field dominates the usual transport by two body collisions and as a result the system behaves like an ideal field. The viscosity caused by this mechanism is anomalous in that it is not constant as a function of shear, but decreases.2 The shear and bulk viscosities in equilibrium states have been measured recently by two groups by measuring the slope of the spectral functions of the energy momentum tensors at the origin. They used lattice gauge theory to calculate the spectral functions. However, there still remain several difficulties which originate from the analytic continuation from the imaginary time calculation on the lattice to the real time, and as a result it is not yet uncertain whether the value of the shear viscosity in the quark-gluon plasma is close to that predicted in the AdS/CFT correspondence or the bulk viscosity increases near the phase transition. In order to circumvent these difficulties, we developed a new method to calculate the viscosities, which does not require the analytic continuation, and carried out a preliminary research on the method.