Title: Now what? – Future directions from probe dynamics

Abstract: Feynman diagrams (in WQFT) generally express observables in terms of iterated integrals. Through IBP reduction such complexity may be reduced; Remarkably, for probes scattering in Kerr, all integrals factorise, conjecturally to any PM order [JH, Jakobsen, Plefka; 2025]. Is it possible that integrals factorise for a general single-worldline theory? This is the topic of this talk. Based on recent developments we motivate why this might be the case. 2PM observables are treated explicitly, before looking at higher PM orders. Finally we discuss applicability beyond probes, specifically resummation of metrics, 2-body scattering, and the SF expansion.