标题： 大N QCD的热力学和亚稳相的本质 显示英文标题

标题： The thermodynamics of large-N QCD and the nature of metastable phases

摘要： 在颜色数量（N）很大的极限下，杨-米尔斯理论和量子色动力学都预期会有一个一阶相变，将束缚的强子相和非束缚的等离子体相分隔开。 这一分离的一个方面是，在大N情况下，可以明确地识别出一个强耦合的等离子体区域。 一阶相变的存在表明，强子相可以被过热，而等离子体相可以被过冷。 如果存在的话，在大N情况下存在的过冷非束缚等离子体具有显著的性质，即它具有负的绝对压力——即压力低于真空的压力。 对于1/N展开中能量密度为1的范围，但超出强子过热相的终点，可以存在一种由普通强子组成的均匀物质的描述，这些强子的质量在1/N展开中为1，并且其温度似乎为$T_H$。 然而，规范描述和微观规范描述之间的联系失效，系统无法完全平衡，正如$N \rightarrow \infty$所示。 相反，在强子描述中，能量被推送到质量任意大的强子上。 对于这样的系统，大体积的热力学极限变得微妙：能量密度不再是强度量。 这些结论成立的前提是标准的大N缩放规则成立，系统在大N下会在强子相和等离子体相之间经历一个一般的二阶相变，并且介子和胶球遵循哈杰恩类型的谱。 显示英文摘要

摘要： In the limit of a large number of colors (N), both Yang-Mills and quantum chromodynamics are expected to have a first-order phase transition separating a confined hadronic phase and a deconfined plasma phase. One aspect of this separation is that at large N, one can unambiguously identify a plasma regime that is strongly coupled. The existence of a first-order transition suggests that the hadronic phase can be superheated and the plasma phase supercooled. The supercooled deconfined plasma present at large N, if it exists, has the remarkable property that it has negative absolute pressure -- i.e. a pressure below that of the vacuum. For energy densities of order unity in a 1/N expansion but beyond the endpoint of the hadronic superheated phase, a description of homogeneous matter composed of ordinary hadrons with masses of order unity in a 1/N expansion can exist, and acts as though it has a temperature of $T_H$ in order unity. However, the connection between the canonical and microcanonical descriptions breaks down and the system cannot fully equilibrate as $N \rightarrow \infty$. Rather, in a hadronic description, energy is pushed to hadrons with masses that are arbitrarily large. The thermodynamic limit of large volumes becomes subtle for such systems: the energy density is no longer intensive. These conclusions follow provided that standard large N scaling rules hold, the system at large N undergoes a generic first-order phase transition between the hadronic and plasma phases and that the mesons and glueballs follow a Hagedorn-type spectrum.