论文标题
QCD中的剪切粘度以及为什么很难计算
Shear viscosity in QCD and why it's hard to calculate
论文作者
论文摘要
剪切粘度是接近平衡的流体系统的动态特性，描述了对剪切流的抗性。在回顾了粘度的物理学以及通常很难计算的原因之后，我讨论了它在QCD理论中的重要性以及执行此类计算的障碍。图解分析需要广泛的重新调整，即使在物理相关的耦合中，收敛也很差。晶格方法需要从欧几里得到Minkowski域的数据的分析延续不足。目前，我们对QCD剪切粘度的最佳结果来自实验的流体动力学解释，第一原理计算落后。
Shear viscosity is a dynamical property of fluid systems close to equilibrium, describing resistance to sheared flow. After reviewing the physics of viscosity and the reason it is usually difficult to compute, I discuss its importance within the theory of QCD and the obstacles to carrying out such a computation. A diagrammatic analysis requires extensive resummations and even then convergence is poor at physically relevant couplings. Lattice approaches require a poorly controlled analytical continuation of data from the Euclidean to the Minkowski domain. At present our best results for QCD shear viscosity come from the hydrodynamical interpretations of experiments, with first-principles calculations trailing behind.
