AI 中文总结
本研究采用模型无关框架，对比指数与高斯成核轮廓，纳入摩擦效应，发现摩擦会显著改变原初黑洞的质量与形成时间，且随机引力波可区分摩擦与无摩擦情形。
AI 中文摘要
早期宇宙中的宇宙学一阶相变（FOPTs）是超出标准模型的诸多场景的令人兴奋的预言。由于气泡成核的随机性，一些因果斑块可能在周围区域完成相变并开始红移后，仍长时间被困在假真空之中。在合适条件下，这些延迟的斑块会变得足够致密，进而坍缩为原初黑洞（PBHs）。因此，人们预期原初黑洞质量、原初黑洞形成时间等特征参数会对潜在的相变动力学过程敏感。在此，我们采用具有固定平均气泡分离尺度（$R_*$）的模型无关框架，直接对比指数型和高斯型成核轮廓对原初黑洞形成的影响。我们还纳入了气泡壁因与周围等离子体相互作用产生的摩擦效应。研究发现，摩擦会显著改变气泡动力学，导致两种成核历史下的原初黑洞质量和形成时间均发生明显变化。此外，一阶相变产生的随机引力波谱可作为探测潜在动力学的互补手段，能够区分气泡壁演化的摩擦效应与无摩擦情形。
英文摘要
Cosmological first-order phase transitions (FOPTs) in the early Universe are an exciting prediction of many beyond the Standard Model scenarios. Owing to the stochastic nature of bubble nucleation, some causal patches may remain trapped in the false vacuum long after the surrounding regions have completed the transition and started to redshift. Under suitable conditions, these delayed patches can become sufficiently overdense to collapse into primordial black holes (PBHs). One therefore expects characteristic parameters, such as the PBH mass and PBH formation time to be sensitive to the underlying phase-transition dynamics. Here, we adopt a model-independent framework with a fixed mean bubble separation scale ($R_*$) to directly compare the impact of exponential and Gaussian nucleation profiles on PBH formation. We further incorporate the effects of friction on the bubble walls arising from interactions with the surrounding plasma. We find that friction significantly modifies the bubble dynamics, leading to significant changes in the PBH mass and formation time for both nucleation histories. Moreover, the stochastic gravitational-wave spectrum generated by the FOPT can provide a complementary probe of the underlying dynamics, allowing the effects of friction on the bubble wall evolution to be distinguished from the frictionless case.
Comments21 pages, 8 figures, 1 table
