中子星振荡中流体动力学普适性的破坏
Breakdown of Hydrodynamic Universality in Neutron Star Oscillations
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中文总结 AI 辅助
该研究发现中子星振荡无法达到流体动力学普适性所需的渐近长波长区域，利用相对论纳维-斯托克斯与以色列-斯图尔特理论对比，证实真实体黏滞性可显著修正振荡谱，将中子星振荡作为探测微观非平衡动力学的直接探针。
中文摘要 AI 辅助
流体动力学普适性是指，相对论耗散流体动力学的不同表述在渐近长波长区域会给出相同预测的性质。本研究表明，中子星振荡不一定能达到该区域：有限的恒星半径限制了可达到的波长，而因果性对微观弛豫时间设定了下限，导致微观与宏观尺度的分离不足以让流体动力学普适性显现。通过对比相对论纳维-斯托克斯（Navier--Stokes）理论与以色列-斯图尔特（Israel--Stewart）理论中的线性振荡，研究发现，即使在最长波长下，真实的体黏滞性也能对振荡谱产生显著修正。这些结果表明，中子星振荡可作为探测超越领先阶流体动力学描述的微观非平衡动力学的直接探针。
英文摘要
Hydrodynamic universality refers to the property that different formulations of relativistic dissipative hydrodynamics yield identical predictions in the asymptotic long-wavelength regime. We show that neutron-star oscillations need not reach this regime. Because the finite stellar radius limits the accessible wavelengths and causality imposes a lower bound on microscopic relaxation times, the separation between microscopic and macroscopic scales can become insufficient for hydrodynamic universality to emerge. Comparing linear oscillations in relativistic Navier--Stokes and Israel--Stewart theories, we find that realistic bulk viscosities can produce sizeable modifications of the oscillation spectrum, even at the longest wavelengths. These results identify neutron-star oscillations as a direct probe of microscopic nonequilibrium dynamics beyond the leading hydrodynamic description.
