The main purpose of the “iTHEMS-phys” study group is to keep a regular seminar series and sometimes have an intensive lecture or workshop on any topics from all fields of theoretical physics. One mainstream, which drives the development of modern physics, is a notion of universality: A fundamental concept in theoretical physics often appears in apparently unrelated areas of physics (and sometimes independently discovered), but one has eventually realized their relationship, or universality. Thus, it is crucially useful to have a common activity like the regular seminar as theoretical physics group, which make us to share the prominent ideas from different areas of physics.