发表机构
Amrita Vishwa Vidyapeetham（阿玛塔维迪亚佩特汉大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究首次在化学非平衡QGP中结合横向膨胀研究剪切粘度诱导的空化，确定临界剪切粘度，并约束其值需避免空化，且JETSCAPE提取值低于该临界值。
AI 中文摘要
我们首次研究了在夸克-胶子等离子体（QGP）中，结合横向膨胀与化学非平衡动力学的剪切粘度诱导的空化现象。化学非平衡通过夸克和胶子的逸度来纳入，其演化与Gubser几何中的因果耗散相对论流体动力学相耦合。利用唯象的温度依赖剪切粘度参数化，我们研究了纵向压力的演化，并确定了其变为负值从而破坏流体动力学描述的条件。我们证明了剪切诱导的空化首先在火球中心（$r=0$）的早期时刻发生，随后向更大的径向距离扩展，横向膨胀加速了其发生，而在化学平衡过程中持续存在。在我们的框架内，我们确定了临界初始剪切粘度 $(\eta/s)_{\rm crit}$，低于该值，在整个QGP演化过程中不会发生空化。由于发现流体动力学能成功描述重离子碰撞的唯象学，我们的结果为剪切粘度提供了约束，要求在QGP演化期间不存在空化。我们发现，从JETSCAPE分析中唯象提取的 $\eta/s$ 低于我们框架中获得的临界剪切粘度 $(\eta/s)_{\rm crit}$。
英文摘要
We present the first study of shear viscosity induced cavitation incorporating transverse expansion alongside chemical non-equilibrium dynamics in the Quark-Gluon Plasma (QGP). Chemical non-equilibrium is incorporated through quark and gluon fugacities, whose evolution is coupled to causal dissipative relativistic hydrodynamics in the Gubser geometry. Using phenomenological temperature-dependent shear viscosity parametrizations, we study the evolution of the longitudinal pressure and identify the conditions under which it becomes negative and thereby breaking down the hydrodynamic description. We demonstrate that shear induced cavitation develops first at the centre of the fireball ($r=0$) at early times and subsequently extends towards larger radial distances, with transverse expansion accelerating its onset, while persisting during chemical equilibration. Within our framework, we determine the critical initial shear viscosity $(η/s)_{\rm crit}$, below which cavitation does not occur throughout the QGP evolution. Since hydrodynamics is found to successfully describe the phenomenology of heavy-ion collisions, our results provide a constraint on shear viscosity requiring the absence of cavitation during the QGP evolution. We find that the phenomenologically extracted $η/s$ from JETSCAPE analyses lie below the critical shear viscosity $(η/s)_{\rm crit}$ obtained in our framework.
Comments10 pages, 8 figures, 1 table
