Speaker
Description
-Quantum evaporation of a black hole is conventionally studied
semiclassically by assuming self-similarity of the black hole
throughout the evaporation process. However, its validity was recently
questioned, and the lifetime of a black hole is conjectured to be much
extended by the memory burden effect. It gives rise to the possibility
that the primordial black holes (PBHs) lighter than 1010 grams are the
dark matter in the Universe. To probe such PBH dark matter, we study
gravitational waves (GWs) induced by primordial curvature
perturbations that produced the PBHs. We find ΩGW(fpeak)h2=7×10−9 with
the peak frequency fpeak=1×103(MPBH/(1010g))−1/2Hz, and the induced
GWs associated with the PBH dark matter whose initial mass is greater
than about 107 grams can be tested by future observations such as
Cosmic Explorer. Furthermore, the scenario can be in principle
confirmed by detecting another GW signal from the mergers of PBHs,
which leads to high-frequency GWs with fpeak=2×1027(MPBH,
ini/(1010g))−1Hz. On the other hand, the induced GW signals stronger
than expected would contradict the dark matter abundance and exclude
the memory burden effect.
