论文标题
早期剪切粘度远非远离全息图
Early-Stage Shear Viscosity far from Equilibrium via Holography
论文作者
论文摘要
剪切粘度是QCD物质的至关重要特性，它决定了超偏移性重型离子碰撞中Quark-Gluon等离子体（QGP）的集体行为。在理论和实验中扩展了近乎平衡的高精度研究，我们考虑到一个事实，即在碰撞中，QGP远非均衡。我们使用AD/CFT对应关系来研究强烈耦合的等离子体，并发现对剪切粘度与熵密度（$η/S $）的比率有重大影响。特别是，我们研究了初始加热阶段，发现降低至60％以下，然后降低到近平衡值的110％。这一发现可能与从RHIC和LHC处的各向异性流量测量中提取传输系数高度相关。
Shear viscosity is a crucial property of QCD matter which determines the collective behavior of the the quark-gluon plasma (QGP) in ultrarelativistic heavy-ion collisions. Extending the near-equilibrium, high-precision investigations in theory and experiment, we take into account the fact that, in a collision, the QGP is generated far from equilibrium. We use the AdS/CFT correspondence to study a strongly coupled plasma and find a significant impact on the ratio of shear viscosity to entropy density, $η/s$. In particular, we investigate the initial heating phase and find a decrease reaching down to below 60% followed by an overshoot to 110% of the near-equilibrium value. This finding might be highly relevant for the extraction of transport coefficients from anisotropic flow measurements at RHIC and LHC.
