Resolving BCFT bulk-cone singularities in braneworlds and top-down holography

Abstract: Two-point functions in BCFTs exhibit characteristic singularities compared to standard CFTs due to reflected light cones. In holographic BCFTs, further singularities, which need not be related to reflected light cones within the BCFT, can arise when the insertion points are connected by bulk null geodesics. The resulting bulk-cone singularities' are expected to be an artifact of thet Hooft limit and should be resolved in string theory. In this work we demonstrate the resolution of bulk-cone singularities in braneworld BCFT duals, where bulk-cone singularities arise from geodesics reflected off the end-of-the-world brane. We show that the geometry near the null geodesics is described by a pp-wave of shockwave form and incroporate string theory corrections, which bounds the two-point functions. We extend this discussion to top-down holography for D1/D5 BCFTs.