Binary Dynamics from Worldline QFT for Scalar-QED

Abstract

We investigate the worldline quantum field theory (WQFT) formalism for scalar-QED and observe that a generating function emerges from WQFT, from which the scattering angle ensues. This generating function bears important similarities with the radial action in that it requires no consideration of exponentiation of lower-order contributions. We demonstrate the computations of this generating function and the resulting scattering angle of a binary system coupled to electromagnetic field up to the third order in the Post-Minkowskian expansion (3PM).

Classical off-shell currents

“…The derivation of WFRs is now well established and described at length in refs. [21,[24][25][26][27]] so here we only consider briefly EM. Our treatment of color variables is equivalent to ref.…”

“…In addition, the interaction vertices propagating n-quantum fluctuations of the worldline variables can be compactly written as (see also ref. [27])…”

“…In this paper we are concerned with off-shell currents in the classical limit from the perspective of Kosower-Maybee-O'Connell (KMOC) [16][17][18][19][20], the Worldline Quantum Field Theory [21][22][23][24][25][26][27][28] and their connection. Throughout, we will focus on the study of the classical limit of the tree-level off-shell current…”