Non-Perturbative Asymptotic Improvement of Perturbation Theory and Mellin-Barnes Representation

Abstract

Using a method mixing Mellin-Barnes representation and Borel resummation we show how to obtain hyperasymptotic expansions from the (divergent) formal power series which follow from the perturbative evaluation of arbitrary "$N$-point" functions for the simple case of zero-dimensional ${\varphi }^4$ field theory. This hyperasymptotic improvement appears from an iterative procedure, based on inverse factorial expansions, and gives birth to interwoven non-perturbative partial sums whose coefficients are related to the perturbative ones by an interesting resurgence phenomenon. It is a non-perturbative improvement in the sense that, for some optimal truncations of the partial sums, the remainder at a given hyperasymptotic level is exponentially suppressed compared to the remainder at the preceding hyperasymptotic level. The Mellin-Barnes representation allows our results to be automatically valid for a wide range of the phase of the complex coupling constant, including Stokes lines. A numerical analysis is performed to emphasize the improved accuracy that this method allows to reach compared to the usual perturbative approach, and the importance of hyperasymptotic optimal truncation schemes.

v2: one reference added, one paragraph added in the conclusions, small changes in the text, corrected typos; v3: published version

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Cited by in corpus (5)

• Multiple Series Representations of $N$-fold Mellin-Barnes Integrals
• On convergent series representations of Mellin-Barnes integrals
• Resummation of Threshold, Low- and High-Energy Expansions for Heavy-Quark Correlators
• Complex Path Integrals and the Space of Theories
• Effective Approaches in and Beyond the MSSM : applications to Higgs Physics and Dark Matter observables