3D Gravity, Point Particles and Liouville Theory
Kirill Krasnov
TL;DR
The paper proposes a quantum bulk/boundary correspondence between 3D gravity with negative cosmological constant and Liouville field theory (LFT), arguing that LFT non-normalizable states correspond to bulk point particles. It grounds this in the semiclassical limit by matching the gravity action for AdS with a line of conical singularities to the fixed-area Liouville action, with the identification $Q^2 = \frac{l}{4G\hbar}$ and the central charge $c_L = 1+6Q^2$. The authors demonstrate that the boundary vertex operators with $0<\alpha<Q/2$ implement bulk defects and that the mass–deficit relation $M l = \Delta+\bar{\Delta}$ emerges from the CFT data, while the bulk/boundary partition functions agree in the semiclassical regime. They discuss broader implications for holography, lattice quantum gravity models, and potential extensions to black hole physics and AdS$_3$/string theory, indicating a rich interplay between quantum LFT and 3D quantum gravity.
Abstract
This paper elaborates on the bulk/boundary relation between negative cosmological constant 3D gravity and Liouville field theory (LFT). We develop an interpretation of LFT non-normalizable states in terms of particles moving in the bulk. This interpretation is suggested by the fact that ``heavy'' vertex operators of LFT create conical singularities and thus should correspond to point particles moving inside AdS. We confirm this expectation by comparing the (semi-classical approximation to the) LFT two-point function with the (appropriately regularized) gravity action evaluated on the corresponding metric.
