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Exact solutions of Dyson-Schwinger equations for iterated one-loop integrals and propagator-coupling duality

D. J. Broadhurst·D. Kreimer
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Abstract

The Hopf algebra of undecorated rooted trees has tamed the combinatorics of perturbative contributions, to anomalous dimensions in Yukawa theory and scalar $ϕ^3$ theory, from all nestings and chainings of a primitive self-energy subdivergence. Here we formulate the nonperturbative problems which these resummations approximate. For Yukawa theory, at spacetime dimension $d=4$, we obtain an integrodifferential Dyson-Schwinger equation and solve it parametrically in terms of the complementary error function. For the scalar theory, at $d=6$, the nonperturbative problem is more severe; we transform it to a nonlinear fourth-order differential equation. After intensive use of symbolic computation we find an algorithm that extends both perturbation series to 500 loops in 7 minutes. Finally, we establish the propagator-coupling duality underlying these achievements making use of the Hopf structure of Feynman diagrams.

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D. J. Broadhurst, D. Kreimer. 2000-12-17. Exact solutions of Dyson-Schwinger equations for iterated one-loop integrals and propagator-coupling duality. https://doi.org/10.1016/s0550-3213(01)00071-2

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