Lambert-W solves the noncommutative $Φ^4$-model

We show that the closed Dyson-Schwinger equation for the 2-point function of the noncommutative λϕ42-model can be rearranged into the boundary value problem Ψ(a+,b+)Ψ(a−,b−)=Ψ(a+,b−)Ψ(a−,b+) for a sectionally holomorphic function Ψ. This expresses the 2-point function as Hilbert transform of an angl...

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Main Authors: Panzer, E, Wulkenhaar, R
Format: Working paper
Published: 2018
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author Panzer, E
Wulkenhaar, R
author_facet Panzer, E
Wulkenhaar, R
author_sort Panzer, E
collection OXFORD
description We show that the closed Dyson-Schwinger equation for the 2-point function of the noncommutative λϕ42-model can be rearranged into the boundary value problem Ψ(a+,b+)Ψ(a−,b−)=Ψ(a+,b−)Ψ(a−,b+) for a sectionally holomorphic function Ψ. This expresses the 2-point function as Hilbert transform of an angle function which itself satisfies a highly non-linear integral equation. A solution of that equation as formal power series in λ shows a surprisingly simple structure. The solution to 10th order is matched by Stirling numbers of the first kind. Its extrapolation to all orders is resummed with the Lagrange-B\"urmann formula to Lambert-W. This leads to an explicit exact formula of the 2-point function, real-analytic at any coupling constant λ>−1/(2log2), in terms of Lambert-W.
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spelling oxford-uuid:972224ac-f3b2-42a9-a4bf-8fe4deedacd62022-03-26T23:57:22ZLambert-W solves the noncommutative $Φ^4$-modelWorking paperhttp://purl.org/coar/resource_type/c_8042uuid:972224ac-f3b2-42a9-a4bf-8fe4deedacd6Symplectic Elements at Oxford2018Panzer, EWulkenhaar, RWe show that the closed Dyson-Schwinger equation for the 2-point function of the noncommutative λϕ42-model can be rearranged into the boundary value problem Ψ(a+,b+)Ψ(a−,b−)=Ψ(a+,b−)Ψ(a−,b+) for a sectionally holomorphic function Ψ. This expresses the 2-point function as Hilbert transform of an angle function which itself satisfies a highly non-linear integral equation. A solution of that equation as formal power series in λ shows a surprisingly simple structure. The solution to 10th order is matched by Stirling numbers of the first kind. Its extrapolation to all orders is resummed with the Lagrange-B\"urmann formula to Lambert-W. This leads to an explicit exact formula of the 2-point function, real-analytic at any coupling constant λ>−1/(2log2), in terms of Lambert-W.
spellingShingle Panzer, E
Wulkenhaar, R
Lambert-W solves the noncommutative $Φ^4$-model
title Lambert-W solves the noncommutative $Φ^4$-model
title_full Lambert-W solves the noncommutative $Φ^4$-model
title_fullStr Lambert-W solves the noncommutative $Φ^4$-model
title_full_unstemmed Lambert-W solves the noncommutative $Φ^4$-model
title_short Lambert-W solves the noncommutative $Φ^4$-model
title_sort lambert w solves the noncommutative φ 4 model
work_keys_str_mv AT panzere lambertwsolvesthenoncommutativeph4model
AT wulkenhaarr lambertwsolvesthenoncommutativeph4model