Degree two Gopakumar-Vafa invariants of local curves
Ben Davison, Naoki Koseki
TL;DR
The paper develops a detailed framework to compute degree-two Gopakumar–Vafa invariants for local curves Tot_C(N) with a rank-two bundle N and canonical determinant, using a two-part strategy tied to Hitchin fibrations and nearby hyperplanes. For genus-two bases, the authors carry out an explicit stratification of the Hitchin base, perform a degeneracy-locus calculation, and determine fibrewise GV contributions via HOMFLY polynomials, culminating in exact n_{g,2[C]} values and confirming GV/GW in this case. They also present a higher-genus analysis, deriving vanishing and leading nonzero terms for n_{g,2[C]}(Tot_C(L)) and establishing GV/GW correspondences in broader genus regimes with a perverse-sheaf framework. The results hinge on a concrete realization of moduli spaces as critical loci, explicit cohomology computations for M_L(2,1), and a careful tally of spectral-curve degeneracies, including generalized de Jonquières divisors. Overall, the work advances the GV/GW program for local curves by providing both exact genus-two invariants and structured higher-genus evidence via Hitchin-theoretic and degeneracy-locus methods.
Abstract
We investigate the Gopakumar-Vafa (GV) theory of local curves, namely, the total spaces of rank two vector bundles with canonical determinant on smooth projective curves. Under a certain genericity condition on the rank two bundles, we propose a general mechanism to compute the degree two GV invariants of local curves. In particular, we determine all the degree two GV invariants when the base curve has genus two. Combined with previous work by Bryan and Pandharipande, we obtain the GV/GW correspondence in this case. When the base curve has genus greater than two, we calculate GV invariants for some extremal genera, providing evidence for the GV/GW conjecture for curves of higher genus.
