Primordial black holes from an interrupted phase transition

We propose a new mechanism of primordial black hole formation via an interrupted 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…

• IF
  Institute for Basic Science

  Award: IBS-R018-D1
• EA
  Engineering and Physical Sciences Research Council

  Awards: EP/V002821/1, ST/X000753/1
• SA
  Science and Technology Facilities Council

  Award: ST/X000753/1