PIRSA:26010092

Dynamical Black Hole Entropy as an Adiabatic Invariant Hamiltonian

Yokokura, Y. (2026). Dynamical Black Hole Entropy as an Adiabatic Invariant Hamiltonian. Perimeter Institute. https://pirsa.org/26010092

Yokokura, Yuki. Dynamical Black Hole Entropy as an Adiabatic Invariant Hamiltonian. Perimeter Institute, Jan. 22, 2026, https://pirsa.org/26010092 

          @misc{ pirsa_PIRSA:26010092,
            doi = {10.48660/26010092},
            url = {https://pirsa.org/26010092},
            author = {Yokokura, Yuki},
            keywords = {Quantum Gravity},
            language = {en},
            title = {Dynamical Black Hole Entropy as an Adiabatic Invariant Hamiltonian},
            publisher = {Perimeter Institute},
            year = {2026},
            month = {jan},
            note = {PIRSA:26010092 see, \url{https://pirsa.org}}
          }

Yuki Yokokura RIKEN

Talk numberPIRSA:26010092
DOI10.48660/26010092
Collection
Talk Type Scientific Series
Subject

Abstract

We study thermodynamics of spherically-symmetric spacetime with the aim of exploring spacetime entropy as an adiabatic invariant. We first describe the geometry and dynamics in terms of a local frame adapted to spherical foliations and find a geometro-hydrodynamic interpretation: the spacetime can be viewed as the worldvolume of a concentric stack of "gravitational bubbles", spherical collective modes with the Misner-Sharp energy density and a geometric pressure. We then introduce a notion of work and heat, and investigate the covariant phase space of a thermodynamic action corresponding to the adiabatic boundary condition. Identifying the phase space with the thermodynamic state space, these should provide the foundation for the spacetime thermodynamics. As an example, we apply this to the apparent horizon and employ Caratheodory’s idea, to derive the entropy of the dynamical horizon as an adiabatic-invariant Hamiltonian. This agrees with the Bekenstein-Hawking formula for the surface area of the apparent horizon, where a dynamical version of Hawking temperature appears. [arXiv: 2601.03077 + to appear]