论文标题
相对论动力学理论中的流体动力发电机
Hydrodynamic generators in relativistic kinetic theory
论文作者
论文摘要
我们将非平衡梯度校正恢复到玻尔兹曼方程在松弛时间近似（RTA）中演变的单粒子分布函数。我们首先研究了经历Bjorken扩展的系统，并表明，在持续的放松时间，RTA Boltzmann方程在后期（即在非流动力模式的衰减之后）的精确解决方案会产生Borel重新亮相Chapman-Enskog系列。将这种对应关系扩展到没有Bjorken对称性的系统中，我们为RTA动力学理论构建了一个（3+1）二维流体动力学生成器，这是Chapman-Enskog系列不可或缺的代表，以消失的非流动力模式消失。放松这个极限，我们在早期发现了一组与查普曼 - 恩科格扩张相关的非流动力模式。表明这些非流动力模式的动力学包括控制流体动力学的出现，作为非平衡流体的有效现场理论描述，即使对于遥远的平衡情况，Knudsen数量最初很大。
We resum the non-equilibrium gradient corrections to a single-particle distribution function evolved by the Boltzmann equation in the relaxation time approximation (RTA). We first study a system undergoing Bjorken expansion and show that, for a constant relaxation time, the exact solution of the RTA Boltzmann equation at late times (i.e. after the decay of non-hydrodynamic modes) generates the Borel resummed Chapman-Enskog series. Extending this correspondence to systems without Bjorken symmetry, we construct a (3+1)-dimensional hydrodynamic generator for RTA kinetic theory, which is an integral representation of the Chapman-Enskog series in the limit of vanishing non-hydrodynamic modes. Relaxing this limit we find at earlier times a set of non-hydrodynamic modes coupled to the Chapman-Enskog expansion. Including the dynamics of these non-hydrodynamic modes is shown to control the emergence of hydrodynamics as an effective field theory description of non-equilibrium fluids, which works well even for far-off-equilibrium situations where the Knudsen number is initially large.
