Goursat's Problem and the Holographic Principle
Enrique Alvarez, Jorge Conde, Lorenzo Hernandez
TL;DR
This work investigates holography for Ricci-flat spacetimes with vanishing cosmological constant by recasting bulk-boundary relations as Goursat (characteristic) problems on a null finite boundary.It develops boundary-to-bulk propagators using Riesz potentials for massless fields and generalized Bessel kernels for massive fields within Milne-type setups, and analyzes their behavior under nontrivial gravitational perturbations.Explicit 3D and 4D examples are derived, including boundary actions, conformal scaling properties, and perturbative corrections, together with a discussion of Brown-York quasilocal energy and its connection to conformal anomalies.The results point to a holographic mapping tied to the finite boundary's conformal structure, with potential connections to conformal field theories and matrix-model frameworks in the zero-$\Lambda$ regime.
Abstract
The whole idea of holography as put forward by Gerard 't Hooft assumes that data on a boundary determine physics in the volume. This corresponds to a Dirichlet problem for euclidean signature, or to a Goursat (characteristic) problem in the lorentzian setting. Is this last aspect of the problem that is explored here for Ricci flat spaces with vanishing cosmological constant.
