Celestial Holography Revisited

Abstract: We revisit the prescription commonly used to define holographic Celestial Correlators as an integral transform of flat space scattering amplitudes. We propose a new prescription according to which holographic Celestial Correlators are a Mellin transform of Minkowski time-ordered correlators extrapolated to the conformal boundary, which is analogous to the extrapolate definition of holographic correlators in AdS/CFT. Our proposal is motivated by an ambiguity in the standard prescription for Celestial Correlators owing the presence of a divergent integral in the definition of conformal primary wave functions. We show that perturbative Celestial Correlators defined in this new way are manifestly recast in terms of corresponding Witten diagrams in Euclidean anti-de Sitter space. We also discuss the possibility of using this definition of Celestial Correlators in terms of bulk correlation functions to explore the non-perturbative properties of Celestial Correlators dual to Conformal Field Theories in Minkowski space.