Séminaire / Seminar GReCO |
| « Gravitational waves induced by primordial black hole fluctuations » |
|
Theodoros Papanikolaou |
|
Ultra-light PBHs with masses $M<5\times 10^8\mathrm{g}$ can
dominate transiently the energy budget of the Universe and reheat the Universe through their evaporation taking place before Big Bang Nucleosynthesis (BBN). In particular, the inhomogeneous distribution of a population of such light PBHs can induce the abundant production of GWs due to second-order gravitational effects. Interestingly enough, we will see in this talk that by using this novel GW portal one can constrain the abundances of such light PBHs, otherwise unconstrained by other direct observational probes, as well the curvature power spectrum on very small scales, not accessible through CMB and LSS probes. Furthermore, by studying the effect of primordial non-Gaussianity on the clustering properties of PBHs, the spectral shape of the aforementioned induced GW signal will change drastically. Notably, by focusing on local-type non-Gaussianity one is met with a distinctive double-peaked GW signal which, depending on the PBH mass and the initial PBH abundance at formation time, can lie within the frequency bands of future GW detectors, namely that of LISA, ET, SKA and BBO; hence rendering this signal potentially detectable by GW experiments and promoting it as a novel portal probing primordial non-Gaussianities. Remarkably, by accounting on BBN bounds on the non-Gaussian GW amplitude one can set at the end model-independent constraints on the effective $\tau_\mathrm{NL}$ on very small scales $k>10^5\mathrm{Mpc}^{-1}$. |
|
lundi 29 avril 2024 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |