Prof. Eiichiro Komatsu, a director at the Max Planck Institute for Astrophysics (Germany), shared his enthusiasm for observational aspects of cosmology and in particular the primordial gravitational waves (GWs) generated during the earliest stage of our Universe, called cosmic inflation. Such GWs distort the space while propagating and leave footprints as the polarizations of the cosmic microwave background (CMB) and as a more direct signal at the GW interferometers. As a world-leading expert on all areas of cosmology, Prof. Komatsu explained the fundamental aspects of CMB and GW observations and their implications in understanding the physics of the primordial Universe (from his remark, "We all came from quantum fluctuations"). He made his talk visually accessible to non-experts while providing fresh interpretations of the data in cosmological observations. He also clarified the importance and excitement of the upcoming LiteBIRD project, the first CMB mission led by Japan, which expects its launch toward the end of 2020's. After the official part of his talk, he remained to be available for both scientific and non-scientific discussions with the audience in an informal setting and exchanged more technically involved thoughts as well as his everyday-life experiences.

Reported by Ryo Namba