Local bulk operators in AdS/CFT: A holographic description of the black hole interior

TL;DR

This paper develops a refined holographic mapping that represents local bulk operators in AdS/CFT, including inside black hole horizons, using complexified boundary coordinates to better understand bulk locality and black hole interior structure.

Contribution

It extends the bulk-to-boundary map to complexified boundaries, enabling local bulk operator representation inside black holes and near singularities, advancing holographic understanding of black hole interiors.

Findings

Successfully represented bulk operators inside BTZ black hole horizons.

Reproduced correct two-point functions, including divergence at the singularity.

Extended the holographic map to complexified boundary coordinates.

Abstract

To gain insight into how bulk locality emerges from the holographic conformal field theory, we reformulate the bulk to boundary map in as local a way as possible. In previous work, we carried out this program for Lorentzian AdS, and showed the support on the boundary could always be reduced to a compact region spacelike separated from the bulk point. In the present work the idea is extended to a complexified boundary, where spatial coordinates are continued to imaginary values. This continuation enables us to represent a local bulk operator as a CFT operator with support on a finite disc on the complexified boundary. We treat general AdS in Poincare coordinates and AdS3 in Rindler coordinates. We represent bulk operators inside the horizon of a BTZ black hole and we verify that the correct bulk two point functions are reproduced, including the divergence when one point hits the BTZ singularity. We comment on the holographic description of black holes formed by collapse and discuss locality and holographic entropy counting at finite N.