BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Theodoros Papanikolaou (APC\, Paris) DTSTART:20210415T140000Z DTEND:20210415T150000Z DTSTAMP:20260423T003251Z UID:IFTWeb/44 DESCRIPTION:Title: Constraining the early universe with ultralight primordial black holes and vice-versa\nby Theodoros Papanikolaou (APC\, Paris) as part of IFT-Ma drid Webinars\n\n\nAbstract\nIn our presentation\, we focus on ultralight PBHs\, not tightly constrained in the literature\, produced naturally duri ng the preheating instability in the context of single-field inflationary models. In particular\, we find that the PBH production mechanism can be s o efficient that PBHs subsequently dominate the content of the universe an d reheating proceeds from their evaporation. Taking into account observati onal constraints on the PBH abundance one can constrain the energy scales at the end of inflation and at the onset of the radiation era. Vice-versa\ , by studying induced second order gravitational waves generated by densit y perturbations underlain by PBHs themselves and taking into account GW ba ck-reaction effects one can set constraints on the initial abundance of PB Hs as a function \nof their mass.\n LOCATION:https://researchseminars.org/talk/IFTWeb/44/ END:VEVENT END:VCALENDAR