Classical double copy of worldline quantum field theory

The recently developed worldline quantum field theory (WQFT) formalism for the classical gravitational scattering of massive bodies is extended to massive, charged point particles coupling bi-adjoint scalar theory, Yang-Mills and dilaton-gravity. We establish a double copy relation in these WQFTs observables (deflection, radiation). fixes locality structure from Using this eikonal phase (or free energy WQFT) computed next-to-leading order (NLO) constants using as well directly finding full agreement. clarify our approach previous studies effective formalism. Finally, equivalence WQFT limit amplitudes shown explicitly up NLO.