标题： 原初黑洞来自中止的相变 显示英文标题

标题： Primordial black holes from an aborted phase transition

摘要： 我们提出了一种新的原初黑洞形成机制，该机制通过在暴胀后的早期物质主导阶段再加热期间的中止相变实现。 在再加热过程中，由在暴胀结束时主导宇宙的无压流体衰变引起，称为再加热子，辐射浴的温度通常会升高，达到最大温度$T_{\rm max}$，然后下降。 我们考虑由温度升高引发的一阶相变，在$T_{\rm max}$高于临界温度但不足以使气泡成核率超过宇宙膨胀的情况下被中止。 尽管气泡从未完全占据空间，但一些气泡可能会成核并膨胀，直到温度再次下降到临界温度。 我们认为这些气泡随着温度进一步下降而收缩并消失，留下具有正密度扰动的宏观球形区域。 这些扰动区域吸积周围的物质（再加热子），最终坍缩成原初黑洞，其质量持续增长直至辐射主导阶段开始。 我们根据$T_{\rm max}$处的气泡成核率估计这些原初黑洞的丰度，并证明从现象学角度来看，其丰度可以显著较大。 显示英文摘要

摘要： We propose a new mechanism of primordial black hole formation via an aborted phase transition during the early matter-dominated stage of reheating after inflation. In reheating, induced by the decay of a pressureless fluid dominating the Universe at the end of inflation, dubbed as reheaton, the temperature of the radiation bath typically increases, reaching a maximum temperature $T_{\rm max}$, and then decreases. We consider a first-order phase transition induced by the increase of the temperature that is aborted as $T_{\rm max}$ is higher than the critical temperature but not sufficiently high for the bubble nucleation rate to overcome the expansion of the Universe. Although bubbles never fully occupy the space, some may be nucleated and expand until the temperature once again decreases to the critical temperature. We argue that these bubbles shrink and disappear as the temperature drops further, leaving behind macroscopic spherical regions with positive density perturbations. These perturbed regions accrete the surrounding matter (reheatons) and eventually collapse into primordial black holes whose mass continues to grow until the onset of radiation domination. We estimate the abundance of these primordial black holes in terms of the bubble nucleation rate at $T_{\rm max}$, and demonstrate that the abundance can be significantly large from a phenomenological perspective.