Symmetry and its spontaneous breaking are basic concepts in modern physics. When a continuum symmetry is spontaneously broken, there appears a gapless mode called the Nambu-Goldstone (NG) mode, which is developed in a Lorentz invariant system, and is known as the Nambu-Goldstone theorem. In this talk, we discuss the generalization of the Nambu-Goldstone theorem to various systems: a non-relativistic system, a system with higher-form symmetries, and open classical and quantum systems. We will show that there also appears an NG mode in these systems when symmetry is spontaneously broken.
Link to the recorded talk:
https://youtu.be/ZikRbDCsCyU
