论文标题
在混合方法中，$η/s $的温度和净化学潜在依赖性
Temperature and net baryochemical potential dependence of $η/s$ in a hybrid approach
论文作者
论文摘要
在这项工作中，研究了剪切粘度与熵密度比$η/s $ $η/s $在流体动力模拟中的质量影响。预测的非恒定$η/s $（$μ_b$）的效果在很大程度上未探索流体动力模拟。先前的研究仅着眼于温度依赖性，甚至仅关注恒定的有效剪切粘度。这项工作通过定性研究杂种方法Smash-Vhlle的广义$η/s $（$ t，μ_b$）的效果来解决此问题，该方法由HADRONES TRANSSION方法Smash和（3+1）D粘性流体动力学代码VHLLE组成。为了减少模型流体动力部分中使用的状态方程的偏差，$η/s $直接以能量密度和净巴里昂数量密度为参数。参数化考虑了在耐药阶段与传输系数匹配的约束以及PQCD结果。这项工作比较了密度依赖性对不同系统尺寸和能量的影响，并将可观察结果与RHIC区域的实验结果进行比较 - bes $ \ sqrt {s_ {s_ {nn}} $ = 7.7-39.0 gev，因为该概括的效果与中间碰撞的效果相关，但在该系统中的效果尤其相关，但在该系统中尤其相关。不消失。结果表明，显式净巴YON数对椭圆流的影响可忽略不计，只有在碰撞的早期阶段相关。此外，我们发现所提出的参数化可能是在非平衡性耐足型传输阶段的剪切粘度的良好代理。
In this work, the qualitative impact of the net baryochemical potential dependence of the shear viscosity to entropy density ratio $η/s$ in hydrodynamical simulations is studied. The effect of a predicted non-constant $η/s$($μ_B$) is largely unexplored in hydrodynamic simulations. Previous studies focus only on a temperature dependence or even only a constant effective shear viscosity. This work addresses this issue by studying qualitatively the effect of a generalized $η/s$($T,μ_B$) in the hybrid approach SMASH-vHLLE, composed of the hadronic transport approach SMASH and the (3+1)d viscous hydrodynamic code vHLLE. In order to reduce the bias of the result on the equation of state used in the hydrodynamic part of the model, $η/s$ is parameterized directly in the energy density and net baryon number density. The parameterization takes into account the constraints of matching to the transport coefficients in the hadronic phase, as well as pQCD results. This work compares the impact of the density dependence for different system sizes and energies and compares the observables with experimental results in the RHIC - BES region $\sqrt{s_{NN}}$ =7.7 - 39.0 GeV, as the effect of this generalization is especially relevant for intermediate collision energies, for which the system is in equilibrium for a relevant amount of time, but the net baryochemical potential does not vanish. It is shown that the effect of an explicit net baryon number dependence on the elliptic flow is negligible and only relevant in the early stages of the collision. Additionally, we find that the proposed parameterization could be a good proxy for the shear viscosity in the non-equilibrium hadronic transport stage.
