Abstract:Primordial black holes (PBHs) are black holes which are believed to have formed in the very early Universe. Recently an idea that asteroid mass PBHs may be dark matter of the Universe is attracting a lot of attention. Their size is microscopic; they are of the size of a hydrogen atom or smaller. In this talk, I first briefly review our knowledge about dark matter and black holes, then introduce the idea of micro PBHs as dark matter of the Universe, and discuss how it can be observationally tested. It turns out that gravitational waves are the key to this observational test.
Bio:Professor Misao Sasaki is currently President of the Asia Pacific Center for Theoretical Physics (APCTP), Benjamin Lee Chair Professor, and Professor at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), The University of Tokyo. He received his Ph.D. in Science from Kyoto University in 1981. He subsequently held faculty positions at Osaka University, Kyoto University, and other institutions, and has served as Director of the Yukawa Institute for Theoretical Physics at Kyoto University and as Deputy Director of the Kavli IPMU at the University of Tokyo. Professor Sasaki has made foundational contributions to early-universe physics, in particular to inflationary cosmology and the theory of cosmological perturbations. His best-known work includes the introduction of the Mukhanov–Sasaki variable and the Mukhanov–Sasaki equation, which has become the standard tool for describing the evolution of primordial quantum fluctuations in the universe. He also systematically established and developed the δN formalism, providing a powerful and broadly applicable framework for calculating nonlinear perturbations generated during inflation. This formalism is a core theoretical bridge connecting models of the early universe with contemporary precision cosmological observations. He has received numerous major international awards, including the Hayashi Chushiro Prize of the Astronomical Society of Japan, the Humboldt Research Award in Germany, and an award from the Daiwa Anglo-Japanese Foundation.
