发表机构
Università di Genova; I.N.F.N. - Sezione di Genova（热那亚大学; 意大利国家核物理研究所热那亚分部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文构造高斯 Schwinger-Keldysh 有效作用量，通过弛豫时间密度的 Stieltjes 变换描述非流体动力学极点和支点割线，并证明动力学理论中的能量依赖弛豫时间近似可实现这些割线。
AI 中文摘要
推迟热关联函数解析延拓到复频率后，表现出非流体动力学极点和支点割线，这些结构约束了流体动力学。我们构造了高斯 Schwinger-Keldysh 有效作用量，其中支点割线由弛豫极点的连续谱产生，响应函数由弛豫时间密度的 Stieltjes 变换控制。动力学 KMS 对称性、正定性和稳定性约束了谱，而端点行为决定了局部支点结构和近边缘极点标度。均匀密度和幂律密度的示例分别展示了超越所有阶的极点-端点分离以及极点-极点和极点-支点终止之间的连续插值。最后，我们证明动力学理论中能量依赖的弛豫时间近似在零动量下为我们的支点割线提供了微观实现。
英文摘要
Retarded thermal correlators, analytically continued to complex frequency, exhibit non-hydrodynamic poles and branch cuts that constrain hydrodynamics. We construct Gaussian Schwinger-Keldysh effective actions in which branch cuts arise from continua of relaxation poles and response functions are governed by Stieltjes transforms of relaxation-time densities. Dynamical KMS symmetry, positivity and stability constrain the spectra, while endpoint behaviour controls the local branch structure and near-edge pole scaling. The illustrative examples of uniform and power-law densities exhibit respectively beyond-all-orders pole-endpoint separation and a continuous interpolation between pole-pole and pole-branch-point termination. Finally, we show that an energy-dependent relaxation-time approximation in kinetic theory provides a microscopic realization of our branch cuts at zero momentum.
Comments40 pages, 5 images
