Speaker
Dr
Yuichiro Tada
(Nagoya University)
Description
Our universe has experienced phase transitions/crossovers several times throughout its thermal history. The gravitational wave (GW) as a cosmological phonograph can record and tell us about such history thanks to its high penetration ability. In particular, GWs sourced by oscillations of density contrasts called scalar-induced GWs (SIGWs), have sensitivity not only to the background expansion rate but also to the plasma sound speed and hence could serve more information on crossovers. Furthermore, they are closely related to the exotic astrophysical object: primordial black holes. In this talk, the potential capabilities of SIGWs will be presented with a view to future observations.
