Hierarchies in relative Picard-Lefschetz theory

Fuente: arXiv
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Auteurs principaux: Berghoff, Marko, Panzer, Erik
Format: Preprint
Publié: 2022
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author Berghoff, Marko
Panzer, Erik
author_facet Berghoff, Marko
Panzer, Erik
contents We prove a relative version of the Picard-Lefschetz theorem, describing the variation of relative homology groups $H_d(Y_t \setminus A_t,B_t\setminus A_t)$ in the fibers of a smooth fiber bundle $Y \to T$ of complex manifolds with $A\cup B \subset Y$ transverse. From this we derive the vanishing of certain iterated variations, a system of constraints dubbed "hierarchy". As applications, we rederive the known analytic structure of Aomoto polylogarithms and massive one loop Feynman integrals. Moreover, we introduce the "simple type" to prove hierarchy constraints in degenerate cases where the Picard-Lefschetz formula does not apply, e.g. the massless triangle or the ice cream cone Feynman diagram. We compare our findings with a "classical" hierarchy of iterated variations (from 1960's $S$-matrix theory) and show how our setup not only explains, but also refines the latter. In order to do so, we need to further resolve the geometry of Feynman motives: We boldly blow up what no one has blown up before.
format Preprint
id arxiv_https___arxiv_org_abs_2212_06661
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Hierarchies in relative Picard-Lefschetz theory
Berghoff, Marko
Panzer, Erik
Mathematical Physics
High Energy Physics - Theory
Algebraic Topology
We prove a relative version of the Picard-Lefschetz theorem, describing the variation of relative homology groups $H_d(Y_t \setminus A_t,B_t\setminus A_t)$ in the fibers of a smooth fiber bundle $Y \to T$ of complex manifolds with $A\cup B \subset Y$ transverse. From this we derive the vanishing of certain iterated variations, a system of constraints dubbed "hierarchy". As applications, we rederive the known analytic structure of Aomoto polylogarithms and massive one loop Feynman integrals. Moreover, we introduce the "simple type" to prove hierarchy constraints in degenerate cases where the Picard-Lefschetz formula does not apply, e.g. the massless triangle or the ice cream cone Feynman diagram. We compare our findings with a "classical" hierarchy of iterated variations (from 1960's $S$-matrix theory) and show how our setup not only explains, but also refines the latter. In order to do so, we need to further resolve the geometry of Feynman motives: We boldly blow up what no one has blown up before.
title Hierarchies in relative Picard-Lefschetz theory
topic Mathematical Physics
High Energy Physics - Theory
Algebraic Topology
url https://arxiv.org/abs/2212.06661