# Massive particles in CCFT A massless particle in Minkowski in a momentum eigenstate reaches a point on the [[0022 Celestial sphere|celestial sphere]] whereas a massive particles does not have this property. For this reason, bulk massive particles do not correspond to local operators in the [[0010 Celestial holography|CCFT]]. Understanding how their non-local nature in celestial holography is an important question. ## Refs - soft theorems - QED (two independent papers) - [[2015#Campiglia, Laddha (May)]]: derive the soft photon theorem from asymptotic symmetry for massive particles by using hyperbolic space to blow up timelike infinity - [[2015#Kapec, Pate, Strominger]]: different formulation - gravity - [[2015#Campiglia, Laddha (Sep)]]: leading and subleading soft graviton theorems for massive particles - boundary-to-bulk propagators - [[2015#Campiglia]]: detailed study of boundary-to-bulk propagators - conformal basis - [[2017#Pasterski, Shao, Strominger (Jan)]]: massive scalar wavefunctions - [[2017#Pasterski, Shao]]: Maxwell and linearised Einstein gravity - [[2020#Law, Zlotnikov (Apr)]]: bosonic non-scalar spins - [[2020#Iacobacci, Muck]] and [[2020#Narayanan]]: fermions - massless limit - [[2024#Fan]] <!-- - Nima: in AdS, decays products all captured by the box, so unstable particles described at infinity - but in momentum basis in flat space, they don't reach infinity - but maybe they do in boost basis (seems intuitive) -->