Rapid cooling of the Cassiopeia A neutron star due to superfluid quantum criticality
仙后座A中子星因超流量子临界性而快速冷却
The rapid cooling of the neutron star in Cassiopeia A is speculated to arise from an enhanced neutrino emission caused by the onset of <SUP>3</SUP>P<SUB>2</SUB>-wave neutron superfluidity in the core. However, the neutrino emissivity due to Cooper-pair breaking and formation is in tension with the requirements for explaining the observed cooling rate. Here, we show that such a rapid cooling can be explained once the non-Fermi liquid behavior of the non-superfluid neutron liquid induced by superfluid quantum criticality is included into the theoretical description of neutron star cooling, without assuming the existence of additional energy loss processes. Our results indicate that the neutron star in Cassiopeia A remains in the thermal relaxation stage, which is greatly prolonged by the non-Fermi liquid behavior. The good agreement between our theoretical results and recent observational cooling data points to the pivotal role played by superfluid quantum criticality in neutron stars.
展开 ▾首次把非费米液体的比热与中微子发射率 T ln(T0/T) 修正耦合进中子星冷却模拟,使 PBF 抑制因子 q 即使在理论下限 0.19 时仍可拟合 Chandra 观测冷却数据;结果预言 Cas A 中子星仍处于被量子临界性大幅延长的热弛豫阶段,并约束了超流/超导临界温度。
既往研究以最小冷却范式解释 Cas A 中子星的快速冷却,将核心 3P2 中子超流开始带来的 Cooper 对破缺—形成(PBF)中微子发射作为额外散热来源 Page+ 2011;但 PBF 发射率中的抑制因子 q 长期存在观测需求与微观计算之间的张力,Leinson 2010 给出的理论值可低至 0.19,而 Shternin+ 2023 的约束使这一矛盾更加突出。本文承接 Zhu+ 2025 的超流量子临界性图像,把非费米液体对中子比热与中微子发射率的 T ln(T0/T) 修正纳入 NSCool 冷却模拟,发现无需直接 Urca 或额外粒子发射即可拟合 Ho+ 2021 的 Chandra 观测,并把 Heinke & Ho 2010 提出的热弛豫阶段假说落到微观机制上。结果还通过 q=0.19–0.76 对应 h≈1.48–1.70,暗示 1S0 与 3P2 超流可共存,与 Yasui+ 2020 的弱竞争图像一致。展望上,ACIS 与 HRC 数据集仍存在系统差,Zhao+ 2025 的独立测量显示仅靠 PBF 也可能解释,未来需要更高精度长期监测和更真实的 EOS/超流微观模型,以检验该机制并进一步约束 h、q 与超流临界温度。
预印本 2024-10-29 · 刊出 2026-05-26 · 收录 2026-08-20