5 papers
Tracking discontinuities in parameter space
Ruth Britto, Holmfridur S. Hannesdottir
We develop a geometric framework in Feynman-parameter space to determine constraints on the sequential discontinuities of Feynman integrals. Our method is based on tracking the def…
Steinmann Violation and Minimal Cuts
Holmfridur S. Hannesdottir, Luke Lippstreu, Andrew J. McLeod +1
The Steinmann relations are known to be violated with respect to some -- but not all -- two-particle momentum channels in massless Feynman integrals. We trace the source of this St…
Soft Factorisation and Exponentiation from Schwinger-Space Geometry
Carolina Figueiredo, Giulio Gambuti, Holmfridur S. Hannesdottir
Infrared divergences in Quantum Field Theory govern the low-energy dynamics of many physical theories, and their understanding is a crucial ingredient in predicting the outcomes of…
Records from the S-Matrix Marathon: Asymptotic Observables
Simon Caron-Huot, Mathieu Giroux, Holmfridur S. Hannesdottir +2
These lectures introduce the notion of asymptotic observables, which are classes of measurable quantities predicted by quantum field theory. In gapped theories with trivial infrare…
Records from the S-Matrix Marathon: Gravitational Physics from Scattering Amplitudes
Miguel Correia, Holmfridur S. Hannesdottir, Giulia Isabella +5
These lecture notes explain how classical gravitational physics emerges from scattering amplitudes. We emphasize the role of different kinematic regimes in probing various aspects…