论文标题

Fokker-Planck方程的跨性函数和流体动物化

Transasymptotics and hydrodynamization of the Fokker-Planck equation for gluons

论文作者

Behtash, A., Kamata, S., Martinez, M., Schaefer, T., Skokov, V.

论文摘要

我们研究了经历了纵向增强不变膨胀的胶子系统的非线性传输过程和流体动物化。在小角度近似中的玻尔兹曼方程框架内描述了动力学。得出了适当的一组粒子分布函数矩的动力学方程。通过研究该动态系统的稳定性和渐近复发性能,我们证明了它的溶液对大(紫外线)和小(IR)有效的knudsen数字表现出截然不同的行为。接近红外策略中的前向吸引子,每一刻的构型关系可以写成多参数跨性别。这种调整方案使我们能够自然地将运输系数的定义扩展到非平衡状态。每个运输系数都通过非流动力模式的非扰动贡献重新归一化。运输系数的knudsen数量依赖性受相应的重新归化基流程方程的控制。在该方案中,阳米尔斯血浆的一个有趣特征是,它在流体动力时表现出短暂的非牛顿行为。在紫外线制度中,矩的解决方案可以写为具有有限收敛半径的幂律渐近系列。我们表明,紫外扰动膨胀的收敛半径是剪切粘度与熵密度比的函数线性增长的。最后,我们比较回调和前进区域中的通用性能与其他动力学模型,包括松弛时间近似和有效的动力学Arnold-Moore-Yaffe(AMY)理论。

We investigate the non-linear transport processes and hydrodynamization of a system of gluons undergoing longitudinal boost-invariant expansion. The dynamics is described within the framework of the Boltzmann equation in the small-angle approximation. The kinetic equations for a suitable set of moments of the one-particle distribution function are derived. By investigating the stability and asymptotic resurgent properties of this dynamical system, we demonstrate, that its solutions exhibit a rather different behavior for large (UV) and small (IR) effective Knudsen numbers. Close to the forward attractor in the IR regime the constitutive relations of each moment can be written as a multiparameter transseries. This resummation scheme allows us to extend the definition of a transport coefficient to the non-equilibrium regime naturally. Each transport coefficient is renormalized by the non-perturbative contributions of the non-hydrodynamic modes. The Knudsen number dependence of the transport coefficient is governed by the corresponding renormalization group flow equation. An interesting feature of the Yang-Mills plasma in this regime is that it exhibits transient non-Newtonian behavior while hydrodynamizing. In the UV regime the solution for the moments can be written as a power-law asymptotic series with a finite radius of convergence. We show that radius of convergence of the UV perturbative expansion grows linearly as a function of the shear viscosity to entropy density ratio. Finally, we compare the universal properties in the pullback and forward attracting regions to other kinetic models including the relaxation time approximation and the effective kinetic Arnold-Moore-Yaffe (AMY) theory.

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