Poisson Structure of the Boundary Gravitons in 3D Gravity with Negative $Λ$
Cedric Troessaert
TL;DR
This work develops a unified Hamiltonian framework for 3D gravity with negative Λ, detailing general asymptotic fall-off conditions and the Poisson structure of boundary gravitons. It identifies a boundary phase-space encoded by $(P,J,M,Q)$ and derives the Dirac bracket and the differentiable generators that act on it, showing that admissible boundary conditions for the Lagrange multipliers correspond to boundary functionals $k_H(M,J,P,Q)$. The authors demonstrate how classic boundary conditions (Conformal, Brown–Henneaux, Chiral, and Constrained Chiral) arise as special cases within this framework, yielding familiar Virasoro and current algebras with explicit central charges and levels. This provides a systematic, model-independent method to study AdS$_3$ boundary dynamics and their holographic implications, while clarifying how different boundary choices translate into distinct asymptotic symmetries and boundary theories.
Abstract
We use the hamiltonian formalism to study the asymptotic structure of 3 dimensional gravity with a negative cosmological constant. We start by defining very general fall-off conditions for the canonical variables and study the implied poisson structure of the boundary gravitons. From the allowed differentiable gauge transformations, we can extract all the possible boundary conditions on the lagrange multipliers and the associated boundary hamiltonians. In the last section, we use this general framework to describe some of the previoussly known boundary conditions.
