Universal properties of bulk viscosity near the QCD phase transition
Universal properties of bulk viscosity near the QCD phase transition
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DOI：
10.1016/j.physletb.2008.01.080
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发表时间：
2007-11
影响因子：
4.4
通讯作者：
F. Karsch;D. Kharzeev;K. Tuchin
中科院分区：
文献类型：
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作者：
F. Karsch;D. Kharzeev;K. Tuchin
我们从最近的QCD状态方程的晶格数据中提取了轻夸克存在下热夸克-胶子物质的体粘滞系数。为此，我们扩展了求和规则分析，包括轻夸克的贡献。我们还讨论了普遍性质的体粘滞附近的二阶相变，因为它可能发生在手征极限的QCD在固定的奇异夸克质量和最有可能发生在两味QCD。指出O（4）普适类中重子密度为零时的手征跃迁和Z（2）普适类中手征临界点的跃迁都导致了体粘滞的临界行为。特别是，后者的普适性类意味着发散的体积粘度，这可以被用来作为一个签名的临界点。我们讨论的物理图片背后的体积粘度急剧增加，在我们的分析，并设计可能的实验测试相关现象。
We extract the bulk viscosity of hot quark–gluon matter in the presence of light quarks from the recent lattice data on the QCD equation of state. For that purpose we extend the sum rule analysis by including the contribution of light quarks. We also discuss the universal properties of bulk viscosity in the vicinity of a second-order phase transition, as it might occur in the chiral limit of QCD at fixed strange quark mass and most likely does occur in two-flavor QCD. We point out that a chiral transition in the O(4) universality class at zero baryon density as well as the transition at the chiral critical point which belongs to the Z(2) universality class both lead to the critical behavior of bulk viscosity. In particular, the latter universality class implies the divergence of the bulk viscosity, which may be used as a signature of the critical point. We discuss the physical picture behind the dramatic increase of bulk viscosity seen in our analysis, and devise possible experimental tests of related phenomena.