Report of iTHEMS Special Lecture – How did the Universe Begin? -Inflation Theory & Road to the Proof-

On May 21st, iTHEMS Special Lecture by Dr. Katsuhiko Sato (Professor Emeritus, The University of Tokyo / Director, Research Center for Science Systems, Japan Society for the Promotion of Science) was given at Okochi Hall for more than 100 participants. Dr. Katsuhiko Sato is well known as a scientist who discovered the inflation mechanism of the early Universe in 1981. In the special lecture, Dr. Katsuhiko Sato gave an introduction about the expansion of the universe, mysteries about uniformity & isotropy of the universe, and absense of monopoles. Then Dr. Katsuhiko Sato explained how he got an idea of the inflation mechanism, motivated by Spontaneous-Symmetry-Breaking (SSB) mechanism (SSB was proposed by Dr. Yoichiro Nambu), and explained how these problems are solved by the Inflation mechanism. Dr. Katsuhiko Sato introduced about future missions that will prove firmly the inflation mechanism, including LiteBIRD that will measure B-mode in the polarization of cosmic microwave background in the universe. It was a great coincidence that JAXA announced on the same day, May 21st, that JAXA has made a decision to launch LiteBIRD. We wish the Inflation mechanism proposed by Dr. Katsuhiko Sato will be proved firmly in the near future.