More on Gopakumar-Vafa formula: coefficients $\mathcal{F}_0$ and $\mathcal{F}_1$

Abstract

In Type IIA compactified on a Calabi-Yau threefold, the genus zero and one terms of the Gopakumar-Vafa (GV) formula describe F-terms that are related to genus zero and one topological amplitudes. While for higher-genus terms $\mathcal{F}_g, g\ge 2$, the contribution of a light hypermultiplet can be computed via a sum over Kaluza-Klein harmonics, as has been shown in a recent paper, for $g \leq 1$, the sum diverges and it is better to compute $\mathcal{F}_0$ and $\mathcal{F}_1$ directly in five-dimensional field theory. Such a computation is presented here.