标题： 耗散和噪声对手性流体动力学中波动的影响 显示英文标题

标题： The impact of dissipation and noise on fluctuations in chiral fluid dynamics

摘要： 我们研究了σ场与热火球的流体动力学膨胀耦合下的非平衡演化，以模拟重离子碰撞中的手征相变。在假设耦合系统的总能量守恒的前提下，允许存在耗散过程和涨落。我们使用含组成夸克的线性σ模型来研究手征相变对手征模式的平衡化和激发的影响。夸克流体在局域热平衡中充当一个热库，而σ场则根据半经典的随机朗之万方程演化。当σ场弛豫到与夸克流体的平衡状态时，观察到了过冷和再加热在一级相变中的效应。一级相变中的非平衡涨落导致了σ涨落强度相对于临界点场景的增加。 显示英文摘要

摘要： We investigate the nonequilibrium evolution of the sigma field coupled to a fluid dynamic expansion of a hot fireball to model the chiral phase transition in heavy-ion collisions. The dissipative processes and fluctuations are allowed under the assumption that the total energy of the coupled system is conserved. We use the linear sigma model with constituent quarks to investigate the effects of the chiral phase transition on the equilibration and excitation of the sigma modes. The quark fluid acts as a heat bath in local thermal equilibrium and the sigma field evolves according to a semiclassical stochastic Langevin equation of motion. The effects of supercooling and reheating in a first order phase transition are observed when the sigma field relaxes to equilibrium with the quark fluid. Nonequilibrium fluctuations at the first order phase transition lead to an increase in the intensity of sigma fluctuations in comparison to a scenario with a critical point.