Physics Seminar-“Relic Gravitational Waves from Primordial Black Hole Evaporation” with Dr. Aurora Ireland
Physics Seminar
March 6, 2024
11:00 AM - 12:00 PM
Location
SES 2214
Calendar
Download iCal FileAbstract: Tiny primordial black holes (PBHs) formed from the gravitational collapse of density perturbations in the early universe offer a unique window on these unknown times, presenting one of few ways to probe the small scale primordial power spectrum and inflation. For light PBHs with M<5x10^8g, which evaporate prior to big bang nucleosynthesis, we must infer information about their abundances and other properties from the decay products they leave behind --- in particular, their relic gravitational waves. PBHs are accompanied by distinctive gravitational wave signatures coming from their formation and evaporation as well as potential binary mergers. In this talk, I will explore the features in the stochastic gravitational wave background from gravitons radiated from light evaporating PBHs under a broad range of early cosmological histories. We will see that the spectra generically peak at very high frequencies, motivating the development of novel high frequency gravitational wave detection technologies. The intensity of the peak depends strongly on the expansion history; standard cosmological evolution and early matter dominated scenarios predict a modest peak amplitude while cosmologies with a transient period of stiff equation of state predict huge amplitudes, allowing such scenarios to be constrained on the basis of violation of Neff bounds.
Date posted
Feb 28, 2024
Date updated
Feb 28, 2024