Speaker
Description
Symmetry provides a unifying framework for understanding physical phenomena. Recent developments have broadened this framework to include higher-form symmetry. From this viewpoint, photons can be understood as Nambu–Goldstone modes associated with spontaneously broken higher-form symmetries. So far, however, higher-form symmetry has been discussed mainly in zero-temperature and equilibrium settings, and its consequences for dissipative real-time dynamics remain less well understood. In this talk, we develop an effective field theory for non-equilibrium photon dynamics based on higher-form symmetry and the Schwinger–Keldysh formalism. The theory describes dissipative photon dynamics in insulating media and incorporates the fluctuation–dissipation relation and the second law of thermodynamics as consequences of the underlying symmetry structure, rather than as phenomenological inputs.