UCLA

Boundaries and defects host localized interactions of the dynamic degrees of freedom and provide the certain conditions on the field at the location of them. In guage theories and gravity, the dynamics of the large gauge degrees of freedom is localized on the boundary and are best described within the covariant phase space formalism using the symplectic form and boundary action. When the gravitational effects are strong, these large gauge degrees of freedom dress the on-shell matter action, which can be described using Hamiltonian formulation by integrating out these edge modes. We present the two efficient methods of computing the symplectic form associated with the boundary degrees of freedom. We then consider the near-extremal charged black holes in 4d, where the gravitational effects are enhanced at low temperature and study the Hawking radiation at near-horizon AdS2 using the Hamiltonian formulation, with emphasis on comparing this to the JT gravity. Extending this perspective to study of defects, we develop a Lagrangian based method for computing the higher structure of non-invertible defects and compute the associators of the duality and triality defects in the 4d Maxwell theory. We then consider a family of codimension-1 non-conformal defects in the free non-compact boson theory and relate the two descriptions—localized interaction and discontinuous relations and study its scaling behavior and effects in spectrum.