₂ Invariants of Hourglass Chains via Quadratic Denominator Reduction

We introduce families of four-regular graphs consisting of chains of hourglasses which are attached to a finite kernel. We prove a formula for the ₂ invariant of these hourglass chains, which only depends on the kernel. For different kernels, these hourglass chains typically give rise to different ₂...

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Published in:Symmetry, Integrability and Geometry: Methods and Applications
Date:2021
ISSN:1815-0659
Main Authors: Schnetz, Oliver, Yeats, Karen
Format: Article
Language:English
Published: Інститут математики НАН України 2021
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/211427
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:₂ Invariants of Hourglass Chains via Quadratic Denominator Reduction. Oliver Schnetz and Karen Yeats. SIGMA 17 (2021), 100, 26 pages

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Summary:We introduce families of four-regular graphs consisting of chains of hourglasses which are attached to a finite kernel. We prove a formula for the ₂ invariant of these hourglass chains, which only depends on the kernel. For different kernels, these hourglass chains typically give rise to different ₂ invariants. An exhaustive search for the ₂ invariants of hourglass chains with kernels that have a maximum of ten vertices provides Calabi-Yau manifolds with point-counts which match the Fourier coefficients of modular forms whose weights and levels are [4,8], [4,16], [6,4], and [9,4]. Assuming the completion conjecture, we show that no modular form of weight 2 and level ≤ 1000 corresponds to the ₂ of such hourglass chains. This provides further evidence in favour of the conjecture that curves are absent in ₂ invariants of ⁴ quantum field theory.
ISSN:1815-0659