Almaalol Dekrayat, Kurkela Aleksi, Strickland Michael
Department of Physics, Kent State University, Kent, Ohio 44242, USA.
Theoretical Physics Department, CERN, 1211 Genéve 23, Switzerland.
Phys Rev Lett. 2020 Sep 18;125(12):122302. doi: 10.1103/PhysRevLett.125.122302.
We establish the existence of a far-from-equilibrium attractor in weakly coupled gauge theory undergoing one-dimensional Bjorken expansion. We demonstrate that the resulting far-from-equilibrium evolution is insensitive to certain features of the initial condition, including both the initial momentum-space anisotropy and initial occupancy. We find that this insensitivity extends beyond the energy-momentum tensor to the detailed form of the one-particle distribution function. Based on our results, we assess different procedures for reconstructing the full one-particle distribution function from the energy-momentum tensor along the attractor and discuss implications for the freeze-out procedure used in the phenomenological analysis of ultrarelativistic nuclear collisions.
我们证明了在经历一维 Bjorken 膨胀的弱耦合规范理论中存在一个远离平衡的吸引子。我们表明，由此产生的远离平衡演化对初始条件的某些特征不敏感，包括初始动量空间各向异性和初始占据情况。我们发现这种不敏感性不仅适用于能量 - 动量张量，还适用于单粒子分布函数的详细形式。基于我们的结果，我们评估了沿着吸引子从能量 - 动量张量重建完整单粒子分布函数的不同方法，并讨论了其对超高能核碰撞唯象分析中所使用的冻出过程的影响。
