5D BPS Quivers and KK Towers

TL;DR

This paper investigates BPS quivers in five-dimensional theories compactified on a circle, addressing computational challenges in counting BPS states, and reconstructs KK towers using geometric and gauge-theoretic methods, supported by numerical checks.

Contribution

It introduces a mathematical theorem to handle $L^2$ cohomology issues in Abelian quivers and develops a gauge-theoretic approach for non-Abelian quivers, enabling the reconstruction of KK towers.

Findings

Successfully reconstructed KK towers for Abelian quivers.

Extended numerical checks to electric BPS states in weak coupling.

Connected $L^2$ index with Donaldson-Thomas invariants.

Abstract

We explore BPS quivers for D=5 theories, compactified on a circle and geometrically engineered over local Calabi-Yau 3-folds, for which many of known machineries leading to (refined) indices fail due to the fine-tuning of the superpotential. For Abelian quivers, the counting reduces to a geometric one, but the technically challenging $L^2$ cohomology proved to be essential for sensible BPS spectra. We offer a mathematical theorem to remedy the difficulty, but for non-Abelian quivers, the cohomology approach itself fails because the relevant wavefunctions are inherently gauge-theoretical. For the Cartan part of gauge multiplets, which suffers no wall-crossing, we resort to the D0 picture and reconstruct entire KK towers. We also perform numerical checks using a multi-center Coulombic routine, with a simple hypothesis on the quiver invariants, and extend this to electric BPS states in the weak coupling chamber. We close with a comment on known Donaldson-Thomas invariants and on how $L^2$ index might be read off from these.