Asymptotic dynamics on the worldline for spinning particles

Abstract

There has been a renewed interest in the description of dressed asymptotic states à la Faddeev-Kulish. In this regard, a worldline representation for asymptotic states dressed by radiation at subleading power in the soft expansion, known as the Generalized Wilson Line (GWL) in the literature, has been available for some time, and it recently found applications in the derivation of factorization theorems for scattering processes of phenomenological relevance. In this paper we revisit the derivation of the GWL in the light of the well-known supersymmetric wordline formalism for the relativistic spinning particle. In particular, we discuss the importance of wordline supersymmetry to understand the contribution of the soft background field to the asymptotic dynamics. We also provide a derivation of the GWL for the gluon case, which was not previously available in the literature, thus extending the exponentiation of next-to-soft gauge boson corrections to Yang-Mills theory. Finally, we comment about possible applications in the current research about asymptotic states in scattering amplitudes for gauge and gravity theories and their classical limit.

Light-ray operators, detectors and gravitational event shapes

“…to study radiation in this context both using classical worldline calculations [48][49][50][51][52][53][54] and double copy techniques scattering amplitudes in the classical limit [55,56]. In addition several classical observables like the classical impulse [57], the radiation kernel [57] and the classical spin kick [35,58] were defined in full generality from from the classical limit of matrix elements of appropriate quantum operators.…”

A worldsheet for Kerr

“…Although amplitudes are rooted in quantum field theory, in recent years there has been an explosion of interest in applications of amplitudes to classical physics [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. This is motivated by the applicability of the results for elastic and inelastic [45][46][47][48][49][50][51][52][53][54][55][56][57] gravitational scattering of two massive particles to gravitational-wave physics [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72], as JHEP03(2021)201 well as by the search for the underlying principles behind the double-copy relationship between gauge theory and gravity [4,…”

Light bending from eikonal in worldline quantum field theory

“…Our dressed propagator can also be applied to the description of light by light scattering, and it would be interesting to study amplitudes made up of dressed photon propagators in the case where the spin tensor contributes. Another interesting route would be to explore the so-called generalized Wilson line [72][73][74][75] for photons. Dressed photon propagators are also useful in describing the propagation of light in an arbitrary medium [76] so it would be interesting to consider coupling to matter in addition to gravity.…”