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arXiv · 2102.12383

$c_2$ invariants of hourglass chains via quadratic denominator reduction

Oliver Schnetz·Karen Yeats
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Abstract

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 $c_2$ invariant of these hourglass chains which only depends on the kernel. For different kernels these hourglass chains typically give rise to different $c_2$ invariants. An exhaustive search for the $c_2$ 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 $\leq1000$ corresponds to the $c_2$ of such hourglass chains. This provides further evidence in favour of the conjecture that curves are absent in $c_2$ invariants of $\phi^4$ quantum field theory.

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Oliver Schnetz, Karen Yeats. 2021-02-24. $c_2$ invariants of hourglass chains via quadratic denominator reduction. https://doi.org/10.3842/sigma.2021.100

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