Regular Seminar Gloria Odak (Charles U. Prague)
at: 14:00 room K3.11 abstract: | In this talk, I will revisit results on the construction of Hamiltonian surface charges in general relativity in the presence of a finite timelike boundary, with an emphasis on how different boundary conditions influence the definition of conserved quantities. The analysis, originally published a few years ago [2109.02883], focuses on Dirichlet, Neumann, and York's mixed boundary conditions, and demonstrates how each leads to consistent, integrable charges using canonical methods. These results are shown to match those obtained via a covariant phase space formalism enhanced by a boundary Lagrangian. A key outcome of the study is the identification of an integrable charge for the Einstein-Hilbert action that differs from Komar's and remains well-defined even without Killing symmetries. We also analyze how the charge depends on the choice of boundary conditions, demonstrating that both quasi-local and asymptotic expressions are affected. These findings are relevant to current efforts to understand gravitational dynamics in finite regions and may have implications for the thermodynamics of black holes. |