6 papers
Landau Singularities from Whitney Stratifications
Martin Helmer, Georgios Papathanasiou, Felix Tellander
We demonstrate that the complete and non-redundant set of Landau singularities of Feynman integrals may be explicitly obtained from the Whitney stratification of a certain map. As…
Renormalization of U(1) Gauge Boson Kinetic Mixing
Felix Forner, Felix Tellander
Quantum field theories containing fields with the same quantum numbers allow for mixed kinetic terms in the Lagrangian, leading to off-diagonal elements in the tree-level two-point…
Characterizing Cohen-Macaulay One-Loop Feynman Integrals
Kyrill Michaelsen, Felix Tellander
We study the generalized hypergeometric systems, in the sense of Gel'fand, Kapranov, and Zelevinsky, associated with one-loop Feynman integrals, and determine when their rank is in…
The two-loop Amplituhedron
Gabriele Dian, Elia Mazzucchelli, Felix Tellander
The loop-Amplituhedron is a semialgebraic set in the product of Grassmannians . Recently, many aspects of this geometry for…
Geometric Singularities of Feynman Integrals
Martin Helmer, Felix Tellander
We provide a new method to calculate the full microlocal description of singularities of Feynman integrals. This is done by associating a unique constructible function to the syste…
Spectral Decomposition of Euler-Mellin Integrals
Martin Helmer, Felix Tellander
We consider the spectral decomposition of singularities of integrals and their integrands. Our results apply to any integral of Euler-Mellin type, and thus especially to every scal…