标题： 用压力各向异性揭示中子星观测中的张力 显示英文标题

标题： Revealing tensions in neutron star observations with pressure anisotropy

摘要： 压力各向同性，即径向压力等于切向压力，在研究中子星时通常被假设。然而，多种物理机制，包括介子/K介子凝聚、磁场、超流性、暗物质聚集以及广义相对论的违反，可能导致压力各向异性。这项工作对中子星中的压力各向异性进行了全面测量。我们的分析结合了广泛的核实验约束和多信使天体物理观测，包括引力波探测和电磁观测。采用的贝叶斯框架对状态方程的不确定性进行边缘化，并允许不同中子星之间的各向异性变化。我们发现各向异性相对于各向同性的贝叶斯因子为$e^{0.46}=10^{0.20}=1.58\gtrsim 3:2$。此外，后验结果表明整个种群更倾向于负的压力各向异性，其中GW170817是主要贡献者。个体差异表明各向异性与密度尺度无关，可能归因于磁场、暗物质聚集或对广义相对论的偏离，而不是相变。尽管压力各向异性的证据仍不明确，但这些结果表明压力各向异性可以作为有价值的诊断工具，用于识别中子星建模中缺失的物理现象，或在多信使天文学时代揭示观测之间的矛盾。 显示英文摘要

摘要： Pressure isotropy, i.e., radial pressure equal to tangential pressure, is often assumed when studying neutron stars. However, multiple physical mechanisms, including pion/kaon condensation, magnetic fields, superfluidity, dark matter clustering, and violations of general relativity, can lead to a pressure anisotropy. This work presents a comprehensive measurement of pressure anisotropy in neutron stars. Our analysis incorporates both an extensive set of nuclear experimental constraints and multi-messenger astrophysical observations, including gravitational wave detections and electromagnetic observations. The Bayesian framework employed marginalizes over equation of state uncertainties and allows the anisotropy to vary between individual neutron stars. We find the Bayes factor for anisotropy against isotropy is $e^{0.46}=10^{0.20}=1.58\gtrsim 3:2$. Additionally, the posterior indicates a population-wide preference for negative pressure anisotropy, with GW170817 serving as the primary contributor. The individual variability suggests density-scale-independent anisotropy, potentially attributable to magnetic fields, dark matter clustering, or deviations from general relativity rather than phase transitions. While the evidence for pressure anisotropy remains inconclusive, these results demonstrate that pressure anisotropy can be utilized as a valuable diagnostic tool for identifying missing physics in neutron star modeling or revealing tension among observations in the era of multi-messenger astronomy.