从动理学理论出发的准流体动力学有效场论
Effective field theory of quasi-hydrodynamics from kinetic theory
AI总结：
本文从动理学理论出发构建线性准流体动力学的有效场论框架，证明守恒量与准守恒量可观测量的动力学可按快弛豫时间展开，零阶对应类Israel-Stewart的瞬态流体动力学普适描述，高阶修正满足微观理论的对称性等约束。
AI中文摘要：
准流体动力学描述具有准守恒自由度的系统，即可观测量在有限时间尺度上弛豫，但该时间尺度参数上长于微观弛豫时间，例子包括动理学化学和线性粘弹性。本文从动理学类理论出发，为线性准流体动力学建立了严格的有效场论框架。从任何具有慢自由度的线性化、因果动理学类理论出发，证明守恒量和准守恒量可观测量的精确动力学可在快弛豫时间尺度上进行系统展开。在零阶时，所得方程构成因果、对称双曲型理论，属于合适的瞬态流体动力学普适类，确立了类Israel-Stewart动力学作为慢弛豫模式的普适描述；高阶修正可系统计算，并继承底层微观理论的普适对称性、Onsager关系、正定性和因果性约束。
英文摘要：
Quasi-hydrodynamics describes systems with quasi-conserved degrees of freedom, namely observables that relax on timescales that are finite but parametrically longer than microscopic relaxation times. Examples include kinetic chemistry and linear viscoelasticity. Here, we develop a rigorous effective-field-theory framework for linear quasi-hydrodynamics from kinetic-type theories. Starting from any linearized, causal kinetic-like theory endowed with slow degrees of freedom, we show that the exact dynamics of conserved and quasi-conserved observables admits a systematic expansion in the fast relaxation timescale. At zeroth order, the resulting equations form a causal, symmetric-hyperbolic theory belonging to the appropriate transient-hydrodynamic universality class, establishing Israel-Stewart-like dynamics as the universal description of slow relaxation modes. Higher-order corrections can be computed systematically and inherit universal symmetry, Onsager, positivity, and causality constraints from the underlying microscopic theory.
