Bulk reconstruction in flat holography

TL;DR

This paper develops a method for reconstructing bulk massless fields in flat space using boundary Carrollian conformal field theory, expanding the bulk field in boundary descendants and analyzing the Lorentz-invariant propagator.

Contribution

It introduces a novel bulk reconstruction framework in flat holography based on boundary CCFT, including a detailed analysis of the bulk-boundary propagator for BMS_3/CCFT_2.

Findings

Bulk fields reconstructed from boundary CCFT descendants.

Detailed Lorentz-invariant bulk-boundary propagator for BMS_3/CCFT_2.

Framework capable of probing local bulk physics from boundary theory.

Abstract

In this note, we discuss the bulk reconstruction of massless free fields in flat space from the highest-weight representation of boundary Carrollian conformal field theory (CCFT). We expand the bulk field as a sum of infinite descendants of a primary state defined in the boundary CCFT, and discuss the Lorentz invariant bulk-boundary propagator in detail for the BMS_3/CCFT_2 case. In our calculation, it is necessary to introduce a nonzero mass at the beginning and take it as vanishing at the end. The framework we proposed has the potential to probe local bulk physics from the boundary CCFT.